Add schema apply command and policy support

Cargo.lock

@@ -4547,6 +4547,7 @@ dependencies = [
  "assert_cmd",
  "clap",
  "color-eyre",
+ "lance-index",
  "omnigraph",
  "omnigraph-compiler",
  "omnigraph-server",
@@ -4589,6 +4590,7 @@ dependencies = [
  "clap",
  "color-eyre",
  "futures",
+ "lance-index",
  "omnigraph",
  "omnigraph-compiler",
  "serde",

README.md

@@ -98,7 +98,7 @@ cargo run -p omnigraph-cli -- read \
 ```
 
 Server routes include `/healthz`, `/snapshot`, `/export`, `/read`, `/change`,
-`/ingest`, `/branches`, `/runs`, and `/commits`.
+`/schema/apply`, `/ingest`, `/branches`, `/runs`, and `/commits`.
 
 To require auth, set `OMNIGRAPH_SERVER_BEARER_TOKEN` on the server and set the
 matching bearer token env var in your CLI target config.
@@ -110,6 +110,7 @@ Core repo flow:
 ```bash
 omnigraph init --schema ./schema.pg ./repo.omni
 omnigraph load --data ./data.jsonl --mode overwrite ./repo.omni
+omnigraph schema apply --schema ./next.pg ./repo.omni --json
 omnigraph snapshot ./repo.omni --branch main --json
 omnigraph read --uri ./repo.omni --query ./queries.gq --name get_person --params '{"name":"Alice"}'
 omnigraph change --uri ./repo.omni --query ./queries.gq --name insert_person --params '{"name":"Mina","age":28}'

crates/omnigraph-cli/Cargo.toml

@@ -26,3 +26,4 @@ assert_cmd = "2"
 predicates = "3"
 serde_json = { workspace = true }
 tempfile = { workspace = true }
+lance-index = { workspace = true }

crates/omnigraph-cli/src/main.rs

@@ -14,8 +14,9 @@ use omnigraph_server::api::{
     BranchCreateOutput, BranchCreateRequest, BranchDeleteOutput, BranchListOutput,
     BranchMergeOutput, BranchMergeRequest, ChangeOutput, ChangeRequest, CommitListOutput,
     CommitOutput, ErrorOutput, ExportRequest, IngestOutput, IngestRequest, ReadOutput, ReadRequest,
-    RunListOutput, RunOutput, SnapshotOutput, SnapshotTableOutput, commit_output, ingest_output,
-    read_output, run_output, snapshot_payload,
+    RunListOutput, RunOutput, SchemaApplyOutput, SchemaApplyRequest, SnapshotOutput,
+    SnapshotTableOutput, commit_output, ingest_output, read_output, run_output,
+    schema_apply_output, snapshot_payload,
 };
 use omnigraph_server::{
     AliasCommand, OmnigraphConfig, PolicyAction, PolicyDecision, PolicyEngine, PolicyRequest,
@@ -280,6 +281,19 @@ enum SchemaCommand {
         #[arg(long)]
         json: bool,
     },
+    /// Apply a supported schema migration
+    Apply {
+        /// Repo URI
+        uri: Option<String>,
+        #[arg(long)]
+        target: Option<String>,
+        #[arg(long)]
+        config: Option<PathBuf>,
+        #[arg(long)]
+        schema: PathBuf,
+        #[arg(long)]
+        json: bool,
+    },
 }
 
 #[derive(Debug, Subcommand)]
@@ -448,6 +462,20 @@ struct SchemaPlanOutput<'a> {
     steps: &'a [SchemaMigrationStep],
 }
 
+fn print_schema_apply_human(output: &SchemaApplyOutput) {
+    println!("schema apply for {}", output.uri);
+    println!("supported: {}", if output.supported { "yes" } else { "no" });
+    println!("applied: {}", if output.applied { "yes" } else { "no" });
+    println!("manifest_version: {}", output.manifest_version);
+    if output.steps.is_empty() {
+        println!("no schema changes");
+        return;
+    }
+    for step in &output.steps {
+        println!("- {}", render_schema_plan_step(step));
+    }
+}
+
 fn ensure_local_repo_parent(uri: &str) -> Result<()> {
     if !uri.contains("://") {
         fs::create_dir_all(uri)?;
@@ -1796,6 +1824,39 @@ async fn main() -> Result<()> {
                     print_schema_plan_human(&uri, &plan);
                 }
             }
+            SchemaCommand::Apply {
+                uri,
+                target,
+                config,
+                schema,
+                json,
+            } => {
+                let config = load_cli_config(config.as_ref())?;
+                let bearer_token =
+                    resolve_remote_bearer_token(&config, uri.as_deref(), target.as_deref())?;
+                let uri = resolve_uri(&config, uri, target.as_deref())?;
+                let schema_source = fs::read_to_string(&schema)?;
+                let output = if is_remote_uri(&uri) {
+                    remote_json::<SchemaApplyOutput>(
+                        &http_client,
+                        Method::POST,
+                        remote_url(&uri, "/schema/apply"),
+                        Some(serde_json::to_value(SchemaApplyRequest {
+                            schema_source: schema_source.clone(),
+                        })?),
+                        bearer_token.as_deref(),
+                    )
+                    .await?
+                } else {
+                    let mut db = Omnigraph::open(&uri).await?;
+                    schema_apply_output(&uri, db.apply_schema(&schema_source).await?)
+                };
+                if json {
+                    print_json(&output)?;
+                } else {
+                    print_schema_apply_human(&output);
+                }
+            }
         },
         Command::Snapshot {
             uri,

crates/omnigraph-cli/tests/cli.rs

@@ -1,5 +1,6 @@
 use std::fs;
 
+use lance_index::traits::DatasetIndexExt;
 use omnigraph::db::{Omnigraph, ReadTarget};
 use serde_json::Value;
 use tempfile::tempdir;
@@ -299,6 +300,243 @@ fn schema_plan_json_reports_unsupported_type_change() {
     }));
 }
 
+#[test]
+fn schema_apply_json_applies_supported_migration() {
+    let temp = tempdir().unwrap();
+    let repo = repo_path(temp.path());
+    let schema_path = temp.path().join("next.pg");
+    init_repo(&repo);
+
+    let next_schema = fs::read_to_string(fixture("test.pg")).unwrap().replace(
+        "    age: I32?\n}",
+        "    age: I32?\n    nickname: String?\n}",
+    );
+    fs::write(&schema_path, next_schema).unwrap();
+
+    let output = output_success(
+        cli()
+            .arg("schema")
+            .arg("apply")
+            .arg("--schema")
+            .arg(&schema_path)
+            .arg("--json")
+            .arg(&repo),
+    );
+    let payload: Value = serde_json::from_slice(&output.stdout).unwrap();
+
+    assert_eq!(payload["supported"], true);
+    assert_eq!(payload["applied"], true);
+    assert_eq!(payload["step_count"], 1);
+
+    let db = tokio::runtime::Runtime::new()
+        .unwrap()
+        .block_on(Omnigraph::open(repo.to_string_lossy().as_ref()))
+        .unwrap();
+    assert!(
+        db.catalog().node_types["Person"]
+            .properties
+            .contains_key("nickname")
+    );
+}
+
+#[test]
+fn schema_apply_human_reports_noop() {
+    let temp = tempdir().unwrap();
+    let repo = repo_path(temp.path());
+    let schema_path = fixture("test.pg");
+    init_repo(&repo);
+
+    let output = output_success(
+        cli()
+            .arg("schema")
+            .arg("apply")
+            .arg("--schema")
+            .arg(&schema_path)
+            .arg(&repo),
+    );
+    let stdout = stdout_string(&output);
+
+    assert!(stdout.contains("applied: no"));
+    assert!(stdout.contains("no schema changes"));
+}
+
+#[test]
+fn schema_apply_json_renames_type_and_updates_snapshot() {
+    let temp = tempdir().unwrap();
+    let repo = repo_path(temp.path());
+    let schema_path = temp.path().join("rename.pg");
+    init_repo(&repo);
+
+    let renamed_schema = fs::read_to_string(fixture("test.pg"))
+        .unwrap()
+        .replace("node Person {\n", "node Human @rename_from(\"Person\") {\n")
+        .replace("edge Knows: Person -> Person", "edge Knows: Human -> Human")
+        .replace(
+            "edge WorksAt: Person -> Company",
+            "edge WorksAt: Human -> Company",
+        );
+    fs::write(&schema_path, renamed_schema).unwrap();
+
+    let output = output_success(
+        cli()
+            .arg("schema")
+            .arg("apply")
+            .arg("--schema")
+            .arg(&schema_path)
+            .arg("--json")
+            .arg(&repo),
+    );
+    let payload: Value = serde_json::from_slice(&output.stdout).unwrap();
+    assert_eq!(payload["applied"], true);
+
+    let db = tokio::runtime::Runtime::new()
+        .unwrap()
+        .block_on(Omnigraph::open(repo.to_string_lossy().as_ref()))
+        .unwrap();
+    let snapshot = tokio::runtime::Runtime::new()
+        .unwrap()
+        .block_on(db.snapshot_of(ReadTarget::branch("main")))
+        .unwrap();
+    assert!(snapshot.entry("node:Human").is_some());
+    assert!(snapshot.entry("node:Person").is_none());
+}
+
+#[test]
+fn schema_apply_json_renames_property_and_updates_catalog() {
+    let temp = tempdir().unwrap();
+    let repo = repo_path(temp.path());
+    let schema_path = temp.path().join("rename-property.pg");
+    init_repo(&repo);
+
+    let renamed_schema = fs::read_to_string(fixture("test.pg"))
+        .unwrap()
+        .replace("age: I32?", "years: I32? @rename_from(\"age\")");
+    fs::write(&schema_path, renamed_schema).unwrap();
+
+    let output = output_success(
+        cli()
+            .arg("schema")
+            .arg("apply")
+            .arg("--schema")
+            .arg(&schema_path)
+            .arg("--json")
+            .arg(&repo),
+    );
+    let payload: Value = serde_json::from_slice(&output.stdout).unwrap();
+    assert_eq!(payload["applied"], true);
+
+    let db = tokio::runtime::Runtime::new()
+        .unwrap()
+        .block_on(Omnigraph::open(repo.to_string_lossy().as_ref()))
+        .unwrap();
+    let person = &db.catalog().node_types["Person"];
+    assert!(person.properties.contains_key("years"));
+    assert!(!person.properties.contains_key("age"));
+}
+
+#[test]
+fn schema_apply_json_adds_index_for_existing_property() {
+    let temp = tempdir().unwrap();
+    let repo = repo_path(temp.path());
+    let schema_path = temp.path().join("index.pg");
+    init_repo(&repo);
+
+    let before_index_count = tokio::runtime::Runtime::new().unwrap().block_on(async {
+        let db = Omnigraph::open(repo.to_string_lossy().as_ref())
+            .await
+            .unwrap();
+        let snapshot = db.snapshot_of(ReadTarget::branch("main")).await.unwrap();
+        let dataset = snapshot.open("node:Person").await.unwrap();
+        dataset.load_indices().await.unwrap().len()
+    });
+
+    let indexed_schema = fs::read_to_string(fixture("test.pg"))
+        .unwrap()
+        .replace("name: String @key", "name: String @key @index");
+    fs::write(&schema_path, indexed_schema).unwrap();
+
+    let output = output_success(
+        cli()
+            .arg("schema")
+            .arg("apply")
+            .arg("--schema")
+            .arg(&schema_path)
+            .arg("--json")
+            .arg(&repo),
+    );
+    let payload: Value = serde_json::from_slice(&output.stdout).unwrap();
+    assert_eq!(payload["applied"], true);
+
+    let after_index_count = tokio::runtime::Runtime::new().unwrap().block_on(async {
+        let db = Omnigraph::open(repo.to_string_lossy().as_ref())
+            .await
+            .unwrap();
+        let snapshot = db.snapshot_of(ReadTarget::branch("main")).await.unwrap();
+        let dataset = snapshot.open("node:Person").await.unwrap();
+        dataset.load_indices().await.unwrap().len()
+    });
+    assert!(after_index_count > before_index_count);
+}
+
+#[test]
+fn schema_apply_rejects_unsupported_plan() {
+    let temp = tempdir().unwrap();
+    let repo = repo_path(temp.path());
+    let schema_path = temp.path().join("breaking.pg");
+    init_repo(&repo);
+
+    let breaking_schema = fs::read_to_string(fixture("test.pg"))
+        .unwrap()
+        .replace("age: I32?", "age: I64?");
+    fs::write(&schema_path, breaking_schema).unwrap();
+
+    let output = output_failure(
+        cli()
+            .arg("schema")
+            .arg("apply")
+            .arg("--schema")
+            .arg(&schema_path)
+            .arg(&repo),
+    );
+    let stderr = String::from_utf8_lossy(&output.stderr);
+    assert!(stderr.contains("changing property type"));
+}
+
+#[test]
+fn schema_apply_rejects_when_non_main_branch_exists() {
+    let temp = tempdir().unwrap();
+    let repo = repo_path(temp.path());
+    let schema_path = temp.path().join("next.pg");
+    init_repo(&repo);
+    output_success(
+        cli()
+            .arg("branch")
+            .arg("create")
+            .arg("--from")
+            .arg("main")
+            .arg("--uri")
+            .arg(&repo)
+            .arg("feature"),
+    );
+
+    let next_schema = fs::read_to_string(fixture("test.pg")).unwrap().replace(
+        "    age: I32?\n}",
+        "    age: I32?\n    nickname: String?\n}",
+    );
+    fs::write(&schema_path, next_schema).unwrap();
+
+    let output = output_failure(
+        cli()
+            .arg("schema")
+            .arg("apply")
+            .arg("--schema")
+            .arg(&schema_path)
+            .arg(&repo),
+    );
+    let stderr = String::from_utf8_lossy(&output.stderr);
+    assert!(stderr.contains("schema apply requires a repo with only main"));
+}
+
 #[test]
 fn load_json_outputs_summary_for_main_branch() {
     let temp = tempdir().unwrap();

crates/omnigraph-cli/tests/support/mod.rs

@@ -110,6 +110,10 @@ pub fn write_config(path: &Path, source: &str) {
     fs::write(path, source).unwrap();
 }
 
+pub fn write_file(path: &Path, source: &str) {
+    fs::write(path, source).unwrap();
+}
+
 fn yaml_string(value: &str) -> String {
     format!("'{}'", value.replace('\'', "''"))
 }
@@ -278,6 +282,12 @@ impl SystemRepo {
         path
     }
 
+    pub fn write_file(&self, name: &str, source: &str) -> PathBuf {
+        let path = self.repo.parent().unwrap().join(name);
+        write_file(&path, source);
+        path
+    }
+
     pub fn spawn_server(&self) -> TestServer {
         spawn_server(&self.repo)
     }

crates/omnigraph-cli/tests/system_remote.rs

@@ -2,6 +2,7 @@ mod support;
 
 use std::fs;
 
+use omnigraph::db::Omnigraph;
 use reqwest::blocking::Client;
 use serde_json::json;
 
@@ -217,6 +218,106 @@ query insert_person($name: String, $age: I32) {
     assert!(runs_payload["runs"].as_array().unwrap().len() >= 2);
 }
 
+#[test]
+#[ignore = "requires loopback socket permissions in sandboxed runners"]
+fn remote_schema_apply_via_cli_updates_repo() {
+    let repo = SystemRepo::initialized();
+    let server = repo.spawn_server();
+    let config = repo.write_config("omnigraph.yaml", &remote_yaml_config(&server.base_url));
+    let next_schema = repo.write_file(
+        "next.pg",
+        &fs::read_to_string(fixture("test.pg")).unwrap().replace(
+            "    age: I32?\n}",
+            "    age: I32?\n    nickname: String?\n}",
+        ),
+    );
+
+    let payload = parse_stdout_json(&output_success(
+        cli()
+            .arg("schema")
+            .arg("apply")
+            .arg("--config")
+            .arg(&config)
+            .arg("--schema")
+            .arg(&next_schema)
+            .arg("--json"),
+    ));
+    assert_eq!(payload["applied"], true);
+
+    let db = tokio::runtime::Runtime::new()
+        .unwrap()
+        .block_on(Omnigraph::open(repo.path().to_string_lossy().as_ref()))
+        .unwrap();
+    assert!(
+        db.catalog().node_types["Person"]
+            .properties
+            .contains_key("nickname")
+    );
+}
+
+#[test]
+#[ignore = "requires loopback socket permissions in sandboxed runners"]
+fn remote_schema_apply_rejects_unsupported_plan() {
+    let repo = SystemRepo::initialized();
+    let server = repo.spawn_server();
+    let config = repo.write_config("omnigraph.yaml", &remote_yaml_config(&server.base_url));
+    let breaking_schema = repo.write_file(
+        "breaking.pg",
+        &fs::read_to_string(fixture("test.pg"))
+            .unwrap()
+            .replace("age: I32?", "age: I64?"),
+    );
+
+    let output = output_failure(
+        cli()
+            .arg("schema")
+            .arg("apply")
+            .arg("--config")
+            .arg(&config)
+            .arg("--schema")
+            .arg(&breaking_schema),
+    );
+    let stderr = String::from_utf8_lossy(&output.stderr);
+    assert!(stderr.contains("changing property type"));
+}
+
+#[test]
+#[ignore = "requires loopback socket permissions in sandboxed runners"]
+fn remote_schema_apply_rejects_when_non_main_branch_exists() {
+    let repo = SystemRepo::initialized();
+    output_success(
+        cli()
+            .arg("branch")
+            .arg("create")
+            .arg("--from")
+            .arg("main")
+            .arg("--uri")
+            .arg(repo.path())
+            .arg("feature"),
+    );
+    let server = repo.spawn_server();
+    let config = repo.write_config("omnigraph.yaml", &remote_yaml_config(&server.base_url));
+    let next_schema = repo.write_file(
+        "next.pg",
+        &fs::read_to_string(fixture("test.pg")).unwrap().replace(
+            "    age: I32?\n}",
+            "    age: I32?\n    nickname: String?\n}",
+        ),
+    );
+
+    let output = output_failure(
+        cli()
+            .arg("schema")
+            .arg("apply")
+            .arg("--config")
+            .arg(&config)
+            .arg("--schema")
+            .arg(&next_schema),
+    );
+    let stderr = String::from_utf8_lossy(&output.stderr);
+    assert!(stderr.contains("schema apply requires a repo with only main"));
+}
+
 #[test]
 #[ignore = "requires loopback socket permissions in sandboxed runners"]
 fn remote_read_preserves_projection_order_in_json_and_csv() {

crates/omnigraph-server/Cargo.toml

@@ -29,3 +29,4 @@ futures = { workspace = true }
 tempfile = { workspace = true }
 tower = { workspace = true }
 serial_test = "3"
+lance-index = { workspace = true }

crates/omnigraph-server/src/api.rs

@@ -1,6 +1,9 @@
-use omnigraph::db::{GraphCommit, MergeOutcome, ReadTarget, RunRecord, Snapshot};
+use omnigraph::db::{
+    GraphCommit, MergeOutcome, ReadTarget, RunRecord, SchemaApplyResult, Snapshot,
+};
 use omnigraph::error::{MergeConflict, MergeConflictKind};
 use omnigraph::loader::{IngestResult, LoadMode};
+use omnigraph_compiler::SchemaMigrationStep;
 use omnigraph_compiler::result::QueryResult;
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
@@ -243,6 +246,21 @@ pub struct ChangeRequest {
     pub branch: Option<String>,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SchemaApplyRequest {
+    pub schema_source: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SchemaApplyOutput {
+    pub uri: String,
+    pub supported: bool,
+    pub applied: bool,
+    pub step_count: usize,
+    pub manifest_version: u64,
+    pub steps: Vec<SchemaMigrationStep>,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct IngestRequest {
     pub branch: Option<String>,
@@ -318,6 +336,17 @@ pub fn snapshot_payload(branch: &str, snapshot: &Snapshot) -> SnapshotOutput {
     }
 }
 
+pub fn schema_apply_output(uri: &str, result: SchemaApplyResult) -> SchemaApplyOutput {
+    SchemaApplyOutput {
+        uri: uri.to_string(),
+        supported: result.supported,
+        applied: result.applied,
+        step_count: result.steps.len(),
+        manifest_version: result.manifest_version,
+        steps: result.steps,
+    }
+}
+
 pub fn run_output(run: &RunRecord) -> RunOutput {
     RunOutput {
         run_id: run.run_id.as_str().to_string(),

crates/omnigraph-server/src/lib.rs

@@ -13,8 +13,8 @@ use api::{
     BranchCreateOutput, BranchCreateRequest, BranchDeleteOutput, BranchListOutput,
     BranchMergeOutput, BranchMergeRequest, ChangeOutput, ChangeRequest, CommitListOutput,
     CommitListQuery, ErrorCode, ErrorOutput, ExportRequest, HealthOutput, IngestOutput,
-    IngestRequest, ReadOutput, ReadRequest, RunListOutput, SnapshotQuery, ingest_output,
-    snapshot_payload,
+    IngestRequest, ReadOutput, ReadRequest, RunListOutput, SchemaApplyOutput, SchemaApplyRequest,
+    SnapshotQuery, ingest_output, schema_apply_output, snapshot_payload,
 };
 use axum::body::{Body, Bytes};
 use axum::extract::DefaultBodyLimit;
@@ -362,6 +362,7 @@ pub fn build_app(state: AppState) -> Router {
         .route("/export", post(server_export))
         .route("/read", post(server_read))
         .route("/change", post(server_change))
+        .route("/schema/apply", post(server_schema_apply))
         .route(
             "/ingest",
             post(server_ingest).layer(DefaultBodyLimit::max(INGEST_REQUEST_BODY_LIMIT_BYTES)),
@@ -658,6 +659,31 @@ async fn server_change(
     }))
 }
 
+async fn server_schema_apply(
+    State(state): State<AppState>,
+    actor: Option<Extension<AuthenticatedActor>>,
+    Json(request): Json<SchemaApplyRequest>,
+) -> std::result::Result<Json<SchemaApplyOutput>, ApiError> {
+    let actor_id = actor.as_ref().map(|Extension(actor)| actor.as_str());
+    authorize_request(
+        &state,
+        actor.as_ref().map(|Extension(actor)| actor),
+        PolicyRequest {
+            actor_id: actor_id.map(str::to_string).unwrap_or_default(),
+            action: PolicyAction::SchemaApply,
+            branch: None,
+            target_branch: Some("main".to_string()),
+        },
+    )?;
+    let result = {
+        let mut db = Arc::clone(&state.db).write_owned().await;
+        db.apply_schema(&request.schema_source)
+            .await
+            .map_err(ApiError::from_omni)?
+    };
+    Ok(Json(schema_apply_output(state.uri(), result)))
+}
+
 async fn server_ingest(
     State(state): State<AppState>,
     actor: Option<Extension<AuthenticatedActor>>,

crates/omnigraph-server/src/policy.rs

@@ -19,6 +19,7 @@ pub enum PolicyAction {
     Read,
     Export,
     Change,
+    SchemaApply,
     BranchCreate,
     BranchDelete,
     BranchMerge,
@@ -33,6 +34,7 @@ impl PolicyAction {
             Self::Read => "read",
             Self::Export => "export",
             Self::Change => "change",
+            Self::SchemaApply => "schema_apply",
             Self::BranchCreate => "branch_create",
             Self::BranchDelete => "branch_delete",
             Self::BranchMerge => "branch_merge",
@@ -50,6 +52,7 @@ impl PolicyAction {
         matches!(
             self,
             Self::BranchCreate
+                | Self::SchemaApply
                 | Self::BranchDelete
                 | Self::BranchMerge
                 | Self::RunPublish
@@ -72,6 +75,7 @@ impl FromStr for PolicyAction {
             "read" => Ok(Self::Read),
             "export" => Ok(Self::Export),
             "change" => Ok(Self::Change),
+            "schema_apply" => Ok(Self::SchemaApply),
             "branch_create" => Ok(Self::BranchCreate),
             "branch_delete" => Ok(Self::BranchDelete),
             "branch_merge" => Ok(Self::BranchMerge),
@@ -591,6 +595,7 @@ namespace Omnigraph {
     action "read" appliesTo { principal: Actor, resource: Repo, context: RequestContext };
     action "export" appliesTo { principal: Actor, resource: Repo, context: RequestContext };
     action "change" appliesTo { principal: Actor, resource: Repo, context: RequestContext };
+    action "schema_apply" appliesTo { principal: Actor, resource: Repo, context: RequestContext };
     action "branch_create" appliesTo { principal: Actor, resource: Repo, context: RequestContext };
     action "branch_delete" appliesTo { principal: Actor, resource: Repo, context: RequestContext };
     action "branch_merge" appliesTo { principal: Actor, resource: Repo, context: RequestContext };
@@ -809,4 +814,44 @@ rules:
 
         engine.run_tests(&tests).unwrap();
     }
+
+    #[test]
+    fn schema_apply_uses_target_branch_scope() {
+        let policy: PolicyConfig = serde_yaml::from_str(
+            r#"
+version: 1
+groups:
+  admins: [act-ragnor]
+protected_branches: [main]
+rules:
+  - id: admins-schema-apply
+    allow:
+      actors: { group: admins }
+      actions: [schema_apply]
+      target_branch_scope: protected
+"#,
+        )
+        .unwrap();
+
+        let engine = PolicyCompiler::compile(&policy, "repo").unwrap();
+        let allow = engine
+            .authorize(&PolicyRequest {
+                actor_id: "act-ragnor".to_string(),
+                action: PolicyAction::SchemaApply,
+                branch: None,
+                target_branch: Some("main".to_string()),
+            })
+            .unwrap();
+        assert!(allow.allowed);
+
+        let deny = engine
+            .authorize(&PolicyRequest {
+                actor_id: "act-ragnor".to_string(),
+                action: PolicyAction::SchemaApply,
+                branch: None,
+                target_branch: Some("feature".to_string()),
+            })
+            .unwrap();
+        assert!(!deny.allowed);
+    }
 }

crates/omnigraph-server/tests/server.rs

@@ -5,11 +5,12 @@ use std::path::{Path, PathBuf};
 use axum::Router;
 use axum::body::{Body, to_bytes};
 use axum::http::{Method, Request, StatusCode};
+use lance_index::traits::DatasetIndexExt;
 use omnigraph::db::{Omnigraph, ReadTarget};
 use omnigraph::loader::{LoadMode, load_jsonl};
 use omnigraph_server::api::{
     BranchCreateRequest, BranchMergeRequest, ChangeRequest, ErrorOutput, ExportRequest,
-    IngestRequest, ReadRequest,
+    IngestRequest, ReadRequest, SchemaApplyRequest,
 };
 use omnigraph_server::{AppState, build_app};
 use serde_json::{Value, json};
@@ -86,6 +87,19 @@ rules:
       target_branch_scope: unprotected
 "#;
 
+const SCHEMA_APPLY_POLICY_YAML: &str = r#"
+version: 1
+groups:
+  admins: [act-ragnor]
+protected_branches: [main]
+rules:
+  - id: admins-schema-apply
+    allow:
+      actors: { group: admins }
+      actions: [schema_apply]
+      target_branch_scope: protected
+"#;
+
 fn fixture(name: &str) -> PathBuf {
     PathBuf::from(env!("CARGO_MANIFEST_DIR"))
         .join("../omnigraph/tests/fixtures")
@@ -114,6 +128,16 @@ async fn init_repo_with_schema_and_data(schema: &str, data: &str) -> tempfile::T
     temp
 }
 
+async fn init_repo_with_schema(schema: &str) -> tempfile::TempDir {
+    let temp = tempfile::tempdir().unwrap();
+    let repo = repo_path(temp.path());
+    fs::create_dir_all(&repo).unwrap();
+    Omnigraph::init(repo.to_str().unwrap(), schema)
+        .await
+        .unwrap();
+    temp
+}
+
 fn repo_path(root: &Path) -> PathBuf {
     root.join("server.omni")
 }
@@ -206,6 +230,64 @@ async fn app_for_loaded_repo_with_auth_tokens_and_policy(
     (temp, build_app(state))
 }
 
+async fn app_for_repo_with_auth_tokens_and_policy(
+    schema: &str,
+    tokens: &[(&str, &str)],
+    policy: &str,
+) -> (tempfile::TempDir, Router) {
+    let temp = init_repo_with_schema(schema).await;
+    let repo = repo_path(temp.path());
+    let policy_path = temp.path().join("policy.yaml");
+    fs::write(&policy_path, policy).unwrap();
+    let state = AppState::open_with_bearer_tokens_and_policy(
+        repo.to_string_lossy().to_string(),
+        tokens
+            .iter()
+            .map(|(actor, token)| ((*actor).to_string(), (*token).to_string()))
+            .collect(),
+        Some(&policy_path),
+    )
+    .await
+    .unwrap();
+    (temp, build_app(state))
+}
+
+fn additive_schema_with_nickname() -> String {
+    fs::read_to_string(fixture("test.pg")).unwrap().replace(
+        "    age: I32?\n}",
+        "    age: I32?\n    nickname: String?\n}",
+    )
+}
+
+fn renamed_person_schema() -> String {
+    fs::read_to_string(fixture("test.pg"))
+        .unwrap()
+        .replace("node Person {\n", "node Human @rename_from(\"Person\") {\n")
+        .replace("edge Knows: Person -> Person", "edge Knows: Human -> Human")
+        .replace(
+            "edge WorksAt: Person -> Company",
+            "edge WorksAt: Human -> Company",
+        )
+}
+
+fn renamed_age_schema() -> String {
+    fs::read_to_string(fixture("test.pg"))
+        .unwrap()
+        .replace("age: I32?", "years: I32? @rename_from(\"age\")")
+}
+
+fn indexed_name_schema() -> String {
+    fs::read_to_string(fixture("test.pg"))
+        .unwrap()
+        .replace("name: String @key", "name: String @key @index")
+}
+
+fn unsupported_schema_change() -> String {
+    fs::read_to_string(fixture("test.pg"))
+        .unwrap()
+        .replace("age: I32?", "age: I64?")
+}
+
 async fn json_response(app: &Router, request: Request<Body>) -> (StatusCode, Value) {
     let response = app.clone().oneshot(request).await.unwrap();
     let status = response.status();
@@ -214,6 +296,279 @@ async fn json_response(app: &Router, request: Request<Body>) -> (StatusCode, Val
     (status, value)
 }
 
+#[tokio::test]
+async fn schema_apply_route_updates_repo_for_authorized_admin() {
+    let (temp, app) = app_for_repo_with_auth_tokens_and_policy(
+        &fs::read_to_string(fixture("test.pg")).unwrap(),
+        &[("act-ragnor", "admin-token")],
+        SCHEMA_APPLY_POLICY_YAML,
+    )
+    .await;
+    let schema = additive_schema_with_nickname();
+
+    let request = Request::builder()
+        .method(Method::POST)
+        .uri("/schema/apply")
+        .header("content-type", "application/json")
+        .header("authorization", "Bearer admin-token")
+        .body(Body::from(
+            serde_json::to_vec(&SchemaApplyRequest {
+                schema_source: schema,
+            })
+            .unwrap(),
+        ))
+        .unwrap();
+    let (status, payload) = json_response(&app, request).await;
+
+    assert_eq!(status, StatusCode::OK);
+    assert_eq!(payload["applied"], true);
+    let repo = repo_path(temp.path());
+    let reopened = Omnigraph::open(repo.to_str().unwrap()).await.unwrap();
+    assert!(
+        reopened.catalog().node_types["Person"]
+            .properties
+            .contains_key("nickname")
+    );
+}
+
+#[tokio::test]
+async fn schema_apply_route_requires_schema_apply_policy_permission() {
+    let (_temp, app) = app_for_repo_with_auth_tokens_and_policy(
+        &fs::read_to_string(fixture("test.pg")).unwrap(),
+        &[("act-ragnor", "admin-token")],
+        POLICY_YAML,
+    )
+    .await;
+
+    let request = Request::builder()
+        .method(Method::POST)
+        .uri("/schema/apply")
+        .header("content-type", "application/json")
+        .header("authorization", "Bearer admin-token")
+        .body(Body::from(
+            serde_json::to_vec(&SchemaApplyRequest {
+                schema_source: additive_schema_with_nickname(),
+            })
+            .unwrap(),
+        ))
+        .unwrap();
+    let (status, payload) = json_response(&app, request).await;
+
+    assert_eq!(status, StatusCode::FORBIDDEN);
+    assert_eq!(
+        payload["code"],
+        serde_json::to_value(omnigraph_server::api::ErrorCode::Forbidden).unwrap()
+    );
+}
+
+#[tokio::test]
+async fn schema_apply_route_requires_bearer_token_when_policy_enabled() {
+    let (_temp, app) = app_for_repo_with_auth_tokens_and_policy(
+        &fs::read_to_string(fixture("test.pg")).unwrap(),
+        &[("act-ragnor", "admin-token")],
+        SCHEMA_APPLY_POLICY_YAML,
+    )
+    .await;
+
+    let request = Request::builder()
+        .method(Method::POST)
+        .uri("/schema/apply")
+        .header("content-type", "application/json")
+        .body(Body::from(
+            serde_json::to_vec(&SchemaApplyRequest {
+                schema_source: additive_schema_with_nickname(),
+            })
+            .unwrap(),
+        ))
+        .unwrap();
+    let (status, payload) = json_response(&app, request).await;
+
+    assert_eq!(status, StatusCode::UNAUTHORIZED);
+    assert_eq!(
+        payload["code"],
+        serde_json::to_value(omnigraph_server::api::ErrorCode::Unauthorized).unwrap()
+    );
+}
+
+#[tokio::test]
+async fn schema_apply_route_can_rename_type() {
+    let (temp, app) = app_for_repo_with_auth_tokens_and_policy(
+        &fs::read_to_string(fixture("test.pg")).unwrap(),
+        &[("act-ragnor", "admin-token")],
+        SCHEMA_APPLY_POLICY_YAML,
+    )
+    .await;
+
+    let request = Request::builder()
+        .method(Method::POST)
+        .uri("/schema/apply")
+        .header("content-type", "application/json")
+        .header("authorization", "Bearer admin-token")
+        .body(Body::from(
+            serde_json::to_vec(&SchemaApplyRequest {
+                schema_source: renamed_person_schema(),
+            })
+            .unwrap(),
+        ))
+        .unwrap();
+    let (status, payload) = json_response(&app, request).await;
+
+    assert_eq!(status, StatusCode::OK);
+    assert_eq!(payload["applied"], true);
+    let repo = repo_path(temp.path());
+    let reopened = Omnigraph::open(repo.to_str().unwrap()).await.unwrap();
+    let snapshot = reopened
+        .snapshot_of(ReadTarget::branch("main"))
+        .await
+        .unwrap();
+    assert!(snapshot.entry("node:Human").is_some());
+    assert!(snapshot.entry("node:Person").is_none());
+}
+
+#[tokio::test]
+async fn schema_apply_route_can_rename_property() {
+    let (temp, app) = app_for_repo_with_auth_tokens_and_policy(
+        &fs::read_to_string(fixture("test.pg")).unwrap(),
+        &[("act-ragnor", "admin-token")],
+        SCHEMA_APPLY_POLICY_YAML,
+    )
+    .await;
+
+    let request = Request::builder()
+        .method(Method::POST)
+        .uri("/schema/apply")
+        .header("content-type", "application/json")
+        .header("authorization", "Bearer admin-token")
+        .body(Body::from(
+            serde_json::to_vec(&SchemaApplyRequest {
+                schema_source: renamed_age_schema(),
+            })
+            .unwrap(),
+        ))
+        .unwrap();
+    let (status, payload) = json_response(&app, request).await;
+
+    assert_eq!(status, StatusCode::OK);
+    assert_eq!(payload["applied"], true);
+    let repo = repo_path(temp.path());
+    let reopened = Omnigraph::open(repo.to_str().unwrap()).await.unwrap();
+    let person = &reopened.catalog().node_types["Person"];
+    assert!(person.properties.contains_key("years"));
+    assert!(!person.properties.contains_key("age"));
+}
+
+#[tokio::test]
+async fn schema_apply_route_can_add_index() {
+    let (temp, app) = app_for_repo_with_auth_tokens_and_policy(
+        &fs::read_to_string(fixture("test.pg")).unwrap(),
+        &[("act-ragnor", "admin-token")],
+        SCHEMA_APPLY_POLICY_YAML,
+    )
+    .await;
+    let repo = repo_path(temp.path());
+    let before_index_count = {
+        let db = Omnigraph::open(repo.to_str().unwrap()).await.unwrap();
+        let snapshot = db.snapshot_of(ReadTarget::branch("main")).await.unwrap();
+        let dataset = snapshot.open("node:Person").await.unwrap();
+        dataset.load_indices().await.unwrap().len()
+    };
+
+    let request = Request::builder()
+        .method(Method::POST)
+        .uri("/schema/apply")
+        .header("content-type", "application/json")
+        .header("authorization", "Bearer admin-token")
+        .body(Body::from(
+            serde_json::to_vec(&SchemaApplyRequest {
+                schema_source: indexed_name_schema(),
+            })
+            .unwrap(),
+        ))
+        .unwrap();
+    let (status, payload) = json_response(&app, request).await;
+
+    assert_eq!(status, StatusCode::OK);
+    assert_eq!(payload["applied"], true);
+    let reopened = Omnigraph::open(repo.to_str().unwrap()).await.unwrap();
+    let snapshot = reopened
+        .snapshot_of(ReadTarget::branch("main"))
+        .await
+        .unwrap();
+    let dataset = snapshot.open("node:Person").await.unwrap();
+    let after_index_count = dataset.load_indices().await.unwrap().len();
+    assert!(after_index_count > before_index_count);
+}
+
+#[tokio::test]
+async fn schema_apply_route_rejects_unsupported_plan() {
+    let (_temp, app) = app_for_repo_with_auth_tokens_and_policy(
+        &fs::read_to_string(fixture("test.pg")).unwrap(),
+        &[("act-ragnor", "admin-token")],
+        SCHEMA_APPLY_POLICY_YAML,
+    )
+    .await;
+
+    let request = Request::builder()
+        .method(Method::POST)
+        .uri("/schema/apply")
+        .header("content-type", "application/json")
+        .header("authorization", "Bearer admin-token")
+        .body(Body::from(
+            serde_json::to_vec(&SchemaApplyRequest {
+                schema_source: unsupported_schema_change(),
+            })
+            .unwrap(),
+        ))
+        .unwrap();
+    let (status, payload) = json_response(&app, request).await;
+
+    assert_eq!(status, StatusCode::BAD_REQUEST);
+    assert_eq!(
+        payload["code"],
+        serde_json::to_value(omnigraph_server::api::ErrorCode::BadRequest).unwrap()
+    );
+}
+
+#[tokio::test]
+async fn schema_apply_route_rejects_when_non_main_branch_exists() {
+    let temp = init_repo_with_schema(&fs::read_to_string(fixture("test.pg")).unwrap()).await;
+    let repo = repo_path(temp.path());
+    let mut db = Omnigraph::open(repo.to_str().unwrap()).await.unwrap();
+    db.branch_create("feature").await.unwrap();
+    drop(db);
+
+    let policy_path = temp.path().join("policy.yaml");
+    fs::write(&policy_path, SCHEMA_APPLY_POLICY_YAML).unwrap();
+    let state = AppState::open_with_bearer_tokens_and_policy(
+        repo.to_string_lossy().to_string(),
+        vec![("act-ragnor".to_string(), "admin-token".to_string())],
+        Some(&policy_path),
+    )
+    .await
+    .unwrap();
+    let app = build_app(state);
+
+    let request = Request::builder()
+        .method(Method::POST)
+        .uri("/schema/apply")
+        .header("content-type", "application/json")
+        .header("authorization", "Bearer admin-token")
+        .body(Body::from(
+            serde_json::to_vec(&SchemaApplyRequest {
+                schema_source: additive_schema_with_nickname(),
+            })
+            .unwrap(),
+        ))
+        .unwrap();
+    let (status, payload) = json_response(&app, request).await;
+
+    assert_eq!(status, StatusCode::CONFLICT);
+    assert_eq!(
+        payload["code"],
+        serde_json::to_value(omnigraph_server::api::ErrorCode::Conflict).unwrap()
+    );
+}
+
 struct EnvGuard {
     saved: Vec<(&'static str, Option<String>)>,
 }

crates/omnigraph/src/db/graph_coordinator.rs

@@ -8,7 +8,7 @@ use crate::failpoints;
 use crate::storage::{StorageAdapter, join_uri, normalize_root_uri};
 
 use super::commit_graph::{CommitGraph, GraphCommit};
-use super::manifest::{ManifestCoordinator, Snapshot, SubTableUpdate};
+use super::manifest::{ManifestChange, ManifestCoordinator, Snapshot, SubTableUpdate};
 use super::run_registry::{RunId, RunRecord, RunRegistry, graph_runs_uri, is_internal_run_branch};
 
 const GRAPH_COMMITS_DIR: &str = "_graph_commits.lance";
@@ -208,6 +208,10 @@ impl GraphCoordinator {
         })
     }
 
+    pub(crate) async fn all_branches(&self) -> Result<Vec<String>> {
+        self.manifest.list_branches().await
+    }
+
     pub async fn branch_descendants(&self, name: &str) -> Result<Vec<String>> {
         self.manifest
             .descendant_branches(name)
@@ -414,6 +418,28 @@ impl GraphCoordinator {
         Ok(manifest_version)
     }
 
+    pub(crate) async fn commit_manifest_changes(
+        &mut self,
+        changes: &[ManifestChange],
+    ) -> Result<u64> {
+        let manifest_version = self.manifest.commit_changes(changes).await?;
+        failpoints::maybe_fail("graph_publish.after_manifest_commit")?;
+        Ok(manifest_version)
+    }
+
+    pub(crate) async fn commit_changes_with_actor(
+        &mut self,
+        changes: &[ManifestChange],
+        actor_id: Option<&str>,
+    ) -> Result<PublishedSnapshot> {
+        let manifest_version = self.commit_manifest_changes(changes).await?;
+        let snapshot_id = self.record_graph_commit(manifest_version, actor_id).await?;
+        Ok(PublishedSnapshot {
+            manifest_version,
+            _snapshot_id: snapshot_id,
+        })
+    }
+
     pub(crate) async fn record_graph_commit(
         &mut self,
         manifest_version: u64,

crates/omnigraph/src/db/manifest.rs

@@ -19,7 +19,7 @@ mod repo;
 #[path = "manifest/state.rs"]
 mod state;
 
-use layout::{manifest_uri, open_manifest_dataset};
+use layout::{manifest_uri, open_manifest_dataset, type_name_hash};
 pub(crate) use metadata::TableVersionMetadata;
 #[cfg(test)]
 use metadata::{OMNIGRAPH_ROW_COUNT_KEY, table_version_metadata_for_state};
@@ -36,6 +36,7 @@ use state::{ManifestState, read_manifest_state};
 
 const OBJECT_TYPE_TABLE: &str = "table";
 const OBJECT_TYPE_TABLE_VERSION: &str = "table_version";
+const OBJECT_TYPE_TABLE_TOMBSTONE: &str = "table_tombstone";
 const TABLE_VERSION_MANAGEMENT_KEY: &str = "table_version_management";
 
 /// Immutable point-in-time view of the database.
@@ -85,6 +86,25 @@ impl SubTableUpdate {
     }
 }
 
+#[derive(Debug, Clone)]
+pub(crate) struct TableRegistration {
+    pub(crate) table_key: String,
+    pub(crate) table_path: String,
+}
+
+#[derive(Debug, Clone)]
+pub(crate) struct TableTombstone {
+    pub(crate) table_key: String,
+    pub(crate) tombstone_version: u64,
+}
+
+#[derive(Debug, Clone)]
+pub(crate) enum ManifestChange {
+    Update(SubTableUpdate),
+    RegisterTable(TableRegistration),
+    Tombstone(TableTombstone),
+}
+
 impl SubTableEntry {
     pub(crate) async fn open(&self, root_uri: &str) -> Result<Dataset> {
         open_table_at_version_from_manifest(
@@ -97,6 +117,19 @@ impl SubTableEntry {
     }
 }
 
+pub(crate) fn table_path_for_table_key(table_key: &str) -> Result<String> {
+    if let Some(type_name) = table_key.strip_prefix("node:") {
+        return Ok(format!("nodes/{}", type_name_hash(type_name)));
+    }
+    if let Some(type_name) = table_key.strip_prefix("edge:") {
+        return Ok(format!("edges/{}", type_name_hash(type_name)));
+    }
+    Err(OmniError::manifest(format!(
+        "invalid table key '{}'",
+        table_key
+    )))
+}
+
 /// An update to apply to the manifest via `commit`.
 #[derive(Debug, Clone)]
 pub struct SubTableUpdate {
@@ -245,11 +278,20 @@ impl ManifestCoordinator {
     /// Atomically inserts one immutable `table_version` row per updated table.
     /// The merge-insert commit on `__manifest` is the graph-level publish point.
     pub async fn commit(&mut self, updates: &[SubTableUpdate]) -> Result<u64> {
-        if updates.is_empty() {
+        let changes = updates
+            .iter()
+            .cloned()
+            .map(ManifestChange::Update)
+            .collect::<Vec<_>>();
+        self.commit_changes(&changes).await
+    }
+
+    pub(crate) async fn commit_changes(&mut self, changes: &[ManifestChange]) -> Result<u64> {
+        if changes.is_empty() {
             return Ok(self.version());
         }
 
-        self.dataset = self.publisher.publish(updates).await?;
+        self.dataset = self.publisher.publish(changes).await?;
 
         self.known_state = read_manifest_state(&self.dataset).await?;
         Ok(self.version())

crates/omnigraph/src/db/manifest/layout.rs

@@ -40,6 +40,10 @@ pub(super) fn version_object_id(table_key: &str, version: u64) -> String {
     format!("{}${}", table_key, format_table_version(version))
 }
 
+pub(super) fn tombstone_object_id(table_key: &str, version: u64) -> String {
+    format!("{}$tombstone${}", table_key, format_table_version(version))
+}
+
 pub(super) fn table_id_to_key(request_id: Option<&Vec<String>>) -> lance_namespace::Result<String> {
     match request_id {
         Some(request_id) if request_id.len() == 1 && !request_id[0].is_empty() => {

crates/omnigraph/src/db/manifest/publisher.rs

@@ -15,11 +15,11 @@
 //! This module should disappear once Lance Rust can do branch-aware batch table
 //! version publication against a managed namespace manifest.
 
-use async_trait::async_trait;
 use std::collections::HashMap;
 use std::sync::Arc;
 
 use arrow_array::RecordBatchIterator;
+use async_trait::async_trait;
 use lance::Dataset;
 use lance::dataset::{MergeInsertBuilder, WhenMatched, WhenNotMatched};
 use lance_namespace::NamespaceError;
@@ -27,16 +27,20 @@ use lance_namespace::models::CreateTableVersionRequest;
 
 use crate::error::{OmniError, Result};
 
-use super::layout::{open_manifest_dataset, version_object_id};
+use super::layout::{open_manifest_dataset, tombstone_object_id, version_object_id};
 use super::metadata::parse_namespace_version_request;
 use super::state::{
-    manifest_rows_batch, manifest_schema, read_manifest_entries, read_manifest_state,
+    manifest_rows_batch, manifest_schema, read_manifest_entries, read_registered_table_locations,
+    read_tombstone_versions,
+};
+use super::{
+    ManifestChange, OBJECT_TYPE_TABLE, OBJECT_TYPE_TABLE_TOMBSTONE, OBJECT_TYPE_TABLE_VERSION,
+    SubTableEntry, SubTableUpdate, TableRegistration, TableTombstone,
 };
-use super::{OBJECT_TYPE_TABLE_VERSION, SubTableEntry, SubTableUpdate};
 
 #[async_trait]
 pub(super) trait ManifestBatchPublisher: Send + Sync {
-    async fn publish(&self, updates: &[SubTableUpdate]) -> Result<Dataset>;
+    async fn publish(&self, changes: &[ManifestChange]) -> Result<Dataset>;
 }
 
 pub(super) struct GraphNamespacePublisher {
@@ -47,6 +51,8 @@ pub(super) struct GraphNamespacePublisher {
 #[derive(Debug)]
 struct PendingVersionRow {
     object_id: String,
+    object_type: String,
+    location: Option<String>,
     metadata: Option<String>,
     table_key: String,
     table_version: Option<u64>,
@@ -72,17 +78,13 @@ impl GraphNamespacePublisher {
         &self,
     ) -> Result<(
         Dataset,
-        HashMap<String, ()>,
+        HashMap<String, String>,
         HashMap<(String, u64), SubTableEntry>,
+        HashMap<(String, u64), ()>,
     )> {
         let dataset = self.dataset().await?;
-        let current = read_manifest_state(&dataset).await?;
+        let registered_tables = read_registered_table_locations(&dataset).await?;
         let existing_entries = read_manifest_entries(&dataset).await?;
-        let known_tables = current
-            .entries
-            .iter()
-            .map(|entry| (entry.table_key.clone(), ()))
-            .collect();
         let existing_versions = existing_entries
             .iter()
             .map(|entry| {
@@ -92,67 +94,153 @@ impl GraphNamespacePublisher {
                 )
             })
             .collect();
-        Ok((dataset, known_tables, existing_versions))
+        let existing_tombstones = read_tombstone_versions(&dataset).await?;
+        Ok((
+            dataset,
+            registered_tables,
+            existing_versions,
+            existing_tombstones,
+        ))
     }
 
     fn build_pending_rows(
-        requests: &[CreateTableVersionRequest],
-        known_tables: &HashMap<String, ()>,
+        changes: &[ManifestChange],
+        known_tables: &HashMap<String, String>,
         existing_versions: &HashMap<(String, u64), SubTableEntry>,
+        existing_tombstones: &HashMap<(String, u64), ()>,
     ) -> Result<Vec<PendingVersionRow>> {
         let mut request_versions = HashMap::<(String, u64), ()>::new();
-        let mut rows = Vec::with_capacity(requests.len());
+        let mut known_tables = known_tables.clone();
+        let mut rows = Vec::with_capacity(changes.len());
 
-        for request in requests {
-            let (table_key, table_version, row_count, table_branch, version_metadata) =
-                parse_namespace_version_request(request)
-                    .map_err(|e| OmniError::Lance(e.to_string()))?;
-            if !known_tables.contains_key(table_key.as_str()) {
-                return Err(OmniError::Lance(
-                    NamespaceError::TableNotFound {
-                        message: format!("table {} not found", table_key),
-                    }
-                    .to_string(),
-                ));
-            }
-            if request_versions
-                .insert((table_key.clone(), table_version), ())
-                .is_some()
+        for change in changes {
+            if let ManifestChange::RegisterTable(TableRegistration {
+                table_key,
+                table_path,
+            }) = change
             {
-                return Err(OmniError::Lance(
-                    NamespaceError::ConcurrentModification {
-                        message: format!(
-                            "table version {} already exists for {}",
-                            table_version, table_key
-                        ),
+                if let Some(existing_path) = known_tables.get(table_key) {
+                    if existing_path != table_path {
+                        return Err(OmniError::Lance(
+                            NamespaceError::ConcurrentModification {
+                                message: format!(
+                                    "table {} already exists with different path {}",
+                                    table_key, existing_path
+                                ),
+                            }
+                            .to_string(),
+                        ));
                     }
-                    .to_string(),
-                ));
+                } else {
+                    known_tables.insert(table_key.clone(), table_path.clone());
+                }
+                rows.push(PendingVersionRow {
+                    object_id: table_key.clone(),
+                    object_type: OBJECT_TYPE_TABLE.to_string(),
+                    location: Some(table_path.clone()),
+                    metadata: None,
+                    table_key: table_key.clone(),
+                    table_version: None,
+                    table_branch: None,
+                    row_count: None,
+                });
             }
-            if let Some(existing) = existing_versions.get(&(table_key.clone(), table_version)) {
-                let is_owner_branch_handoff =
-                    existing.row_count == row_count && existing.table_branch != table_branch;
-                if !is_owner_branch_handoff {
-                    return Err(OmniError::Lance(
-                        NamespaceError::ConcurrentModification {
-                            message: format!(
-                                "table version {} already exists for {}",
-                                table_version, table_key
-                            ),
+        }
+
+        for change in changes {
+            match change {
+                ManifestChange::RegisterTable(_) => {}
+                ManifestChange::Update(update) => {
+                    let request = update.to_create_table_version_request();
+                    let (table_key, table_version, row_count, table_branch, version_metadata) =
+                        parse_namespace_version_request(&request)
+                            .map_err(|e| OmniError::Lance(e.to_string()))?;
+                    if !known_tables.contains_key(table_key.as_str()) {
+                        return Err(OmniError::Lance(
+                            NamespaceError::TableNotFound {
+                                message: format!("table {} not found", table_key),
+                            }
+                            .to_string(),
+                        ));
+                    }
+                    if request_versions
+                        .insert((table_key.clone(), table_version), ())
+                        .is_some()
+                    {
+                        return Err(OmniError::Lance(
+                            NamespaceError::ConcurrentModification {
+                                message: format!(
+                                    "table version {} already exists for {}",
+                                    table_version, table_key
+                                ),
+                            }
+                            .to_string(),
+                        ));
+                    }
+                    if let Some(existing) =
+                        existing_versions.get(&(table_key.clone(), table_version))
+                    {
+                        let is_owner_branch_handoff = existing.row_count == row_count
+                            && existing.table_branch != table_branch;
+                        if !is_owner_branch_handoff {
+                            return Err(OmniError::Lance(
+                                NamespaceError::ConcurrentModification {
+                                    message: format!(
+                                        "table version {} already exists for {}",
+                                        table_version, table_key
+                                    ),
+                                }
+                                .to_string(),
+                            ));
                         }
-                        .to_string(),
-                    ));
+                    }
+
+                    rows.push(PendingVersionRow {
+                        object_id: version_object_id(&table_key, table_version),
+                        object_type: OBJECT_TYPE_TABLE_VERSION.to_string(),
+                        location: None,
+                        metadata: Some(version_metadata.to_json_string()?),
+                        table_key,
+                        table_version: Some(table_version),
+                        table_branch,
+                        row_count: Some(row_count),
+                    });
+                }
+                ManifestChange::Tombstone(TableTombstone {
+                    table_key,
+                    tombstone_version,
+                }) => {
+                    if !known_tables.contains_key(table_key.as_str()) {
+                        return Err(OmniError::Lance(
+                            NamespaceError::TableNotFound {
+                                message: format!("table {} not found", table_key),
+                            }
+                            .to_string(),
+                        ));
+                    }
+                    if existing_tombstones.contains_key(&(table_key.clone(), *tombstone_version)) {
+                        return Err(OmniError::Lance(
+                            NamespaceError::ConcurrentModification {
+                                message: format!(
+                                    "table tombstone {} already exists for {}",
+                                    tombstone_version, table_key
+                                ),
+                            }
+                            .to_string(),
+                        ));
+                    }
+                    rows.push(PendingVersionRow {
+                        object_id: tombstone_object_id(table_key, *tombstone_version),
+                        object_type: OBJECT_TYPE_TABLE_TOMBSTONE.to_string(),
+                        location: None,
+                        metadata: None,
+                        table_key: table_key.clone(),
+                        table_version: Some(*tombstone_version),
+                        table_branch: None,
+                        row_count: None,
+                    });
                 }
             }
-
-            rows.push(PendingVersionRow {
-                object_id: version_object_id(&table_key, table_version),
-                metadata: Some(version_metadata.to_json_string()?),
-                table_key,
-                table_version: Some(table_version),
-                table_branch,
-                row_count: Some(row_count),
-            });
         }
 
         Ok(rows)
@@ -170,8 +258,8 @@ impl GraphNamespacePublisher {
 
         for row in rows {
             object_ids.push(row.object_id);
-            object_types.push(OBJECT_TYPE_TABLE_VERSION.to_string());
-            locations.push(None);
+            object_types.push(row.object_type);
+            locations.push(row.location);
             metadata.push(row.metadata);
             table_keys.push(row.table_key);
             table_versions.push(row.table_version);
@@ -214,23 +302,41 @@ impl GraphNamespacePublisher {
         &self,
         requests: &[CreateTableVersionRequest],
     ) -> Result<Dataset> {
-        if requests.is_empty() {
-            return self.dataset().await;
-        }
-
-        let (dataset, known_tables, existing_versions) = self.load_publish_state().await?;
-        let rows = Self::build_pending_rows(requests, &known_tables, &existing_versions)?;
-        self.merge_rows(dataset, rows).await
+        let changes = requests
+            .iter()
+            .cloned()
+            .map(|request| {
+                let (table_key, table_version, row_count, table_branch, version_metadata) =
+                    parse_namespace_version_request(&request)
+                        .map_err(|e| OmniError::Lance(e.to_string()))?;
+                Ok(ManifestChange::Update(SubTableUpdate {
+                    table_key,
+                    table_version,
+                    table_branch,
+                    row_count,
+                    version_metadata,
+                }))
+            })
+            .collect::<Result<Vec<_>>>()?;
+        self.publish(&changes).await
     }
 }
 
 #[async_trait]
 impl ManifestBatchPublisher for GraphNamespacePublisher {
-    async fn publish(&self, updates: &[SubTableUpdate]) -> Result<Dataset> {
-        let requests: Vec<CreateTableVersionRequest> = updates
-            .iter()
-            .map(SubTableUpdate::to_create_table_version_request)
-            .collect();
-        self.publish_requests(&requests).await
+    async fn publish(&self, changes: &[ManifestChange]) -> Result<Dataset> {
+        if changes.is_empty() {
+            return self.dataset().await;
+        }
+
+        let (dataset, known_tables, existing_versions, existing_tombstones) =
+            self.load_publish_state().await?;
+        let rows = Self::build_pending_rows(
+            changes,
+            &known_tables,
+            &existing_versions,
+            &existing_tombstones,
+        )?;
+        self.merge_rows(dataset, rows).await
     }
 }

crates/omnigraph/src/db/manifest/state.rs

@@ -10,7 +10,7 @@ use crate::error::{OmniError, Result};
 
 use super::layout::version_object_id;
 use super::metadata::TableVersionMetadata;
-use super::{OBJECT_TYPE_TABLE, OBJECT_TYPE_TABLE_VERSION};
+use super::{OBJECT_TYPE_TABLE, OBJECT_TYPE_TABLE_TOMBSTONE, OBJECT_TYPE_TABLE_VERSION};
 
 #[derive(Debug, Clone)]
 pub struct SubTableEntry {
@@ -28,6 +28,19 @@ pub(super) struct ManifestState {
     pub(super) entries: Vec<SubTableEntry>,
 }
 
+#[derive(Debug, Clone)]
+struct TableTombstoneEntry {
+    table_key: String,
+    tombstone_version: u64,
+}
+
+#[derive(Debug, Clone)]
+struct ManifestScan {
+    table_locations: HashMap<String, String>,
+    version_entries: Vec<SubTableEntry>,
+    tombstones: Vec<TableTombstoneEntry>,
+}
+
 pub(super) fn manifest_schema() -> SchemaRef {
     Arc::new(Schema::new(vec![
         Field::new("object_id", DataType::Utf8, false),
@@ -48,10 +61,10 @@ pub(super) fn manifest_schema() -> SchemaRef {
 
 pub(super) async fn read_manifest_state(dataset: &Dataset) -> Result<ManifestState> {
     let version = dataset.version().version;
-    let entries = read_manifest_entries(dataset).await?;
+    let scan = read_manifest_scan(dataset).await?;
     let mut latest_versions = HashMap::<String, SubTableEntry>::new();
 
-    for entry in entries {
+    for entry in scan.version_entries {
         match latest_versions.get(&entry.table_key) {
             Some(existing) if existing.table_version >= entry.table_version => {}
             _ => {
@@ -60,13 +73,52 @@ pub(super) async fn read_manifest_state(dataset: &Dataset) -> Result<ManifestSta
         }
     }
 
-    let mut entries: Vec<SubTableEntry> = latest_versions.into_values().collect();
+    let mut tombstones = HashMap::<String, u64>::new();
+    for tombstone in scan.tombstones {
+        match tombstones.get(&tombstone.table_key) {
+            Some(existing) if *existing >= tombstone.tombstone_version => {}
+            _ => {
+                tombstones.insert(tombstone.table_key, tombstone.tombstone_version);
+            }
+        }
+    }
+
+    let mut entries: Vec<SubTableEntry> = latest_versions
+        .into_values()
+        .filter(|entry| {
+            tombstones
+                .get(&entry.table_key)
+                .map(|tombstone_version| *tombstone_version < entry.table_version)
+                .unwrap_or(true)
+        })
+        .collect();
     entries.sort_by(|a, b| a.table_key.cmp(&b.table_key));
 
     Ok(ManifestState { version, entries })
 }
 
 pub(super) async fn read_manifest_entries(dataset: &Dataset) -> Result<Vec<SubTableEntry>> {
+    Ok(read_manifest_scan(dataset).await?.version_entries)
+}
+
+pub(super) async fn read_registered_table_locations(
+    dataset: &Dataset,
+) -> Result<HashMap<String, String>> {
+    Ok(read_manifest_scan(dataset).await?.table_locations)
+}
+
+pub(super) async fn read_tombstone_versions(
+    dataset: &Dataset,
+) -> Result<HashMap<(String, u64), ()>> {
+    Ok(read_manifest_scan(dataset)
+        .await?
+        .tombstones
+        .into_iter()
+        .map(|tombstone| ((tombstone.table_key, tombstone.tombstone_version), ()))
+        .collect())
+}
+
+async fn read_manifest_scan(dataset: &Dataset) -> Result<ManifestScan> {
     let batches: Vec<RecordBatch> = dataset
         .scan()
         .try_into_stream()
@@ -78,6 +130,7 @@ pub(super) async fn read_manifest_entries(dataset: &Dataset) -> Result<Vec<SubTa
 
     let mut table_locations = HashMap::new();
     let mut version_entries = Vec::new();
+    let mut tombstones = Vec::new();
 
     for batch in &batches {
         let object_types = string_column(batch, "object_type")?;
@@ -123,6 +176,13 @@ pub(super) async fn read_manifest_entries(dataset: &Dataset) -> Result<Vec<SubTa
                         version_metadata: TableVersionMetadata::from_json_str(metadata.value(row))?,
                     });
                 }
+                OBJECT_TYPE_TABLE_TOMBSTONE => {
+                    let tombstone_version = required_u64(versions, row, "table_version")?;
+                    tombstones.push(TableTombstoneEntry {
+                        table_key,
+                        tombstone_version,
+                    });
+                }
                 _ => {}
             }
         }
@@ -149,7 +209,11 @@ pub(super) async fn read_manifest_entries(dataset: &Dataset) -> Result<Vec<SubTa
             .then(a.table_version.cmp(&b.table_version))
     });
 
-    Ok(entries)
+    Ok(ManifestScan {
+        table_locations,
+        version_entries: entries,
+        tombstones,
+    })
 }
 
 pub(super) fn entries_to_batch(

crates/omnigraph/src/db/manifest/tests.rs

@@ -132,6 +132,63 @@ async fn test_commit_advances_version() {
     assert_eq!(company.row_count, 0);
 }
 
+#[tokio::test]
+async fn test_commit_changes_can_register_new_table_and_tombstone_old_one() {
+    let dir = tempfile::tempdir().unwrap();
+    let uri = dir.path().to_str().unwrap();
+    let catalog = build_test_catalog();
+
+    let mut mc = ManifestCoordinator::init(uri, &catalog).await.unwrap();
+    let before_version = mc.version();
+    let person_entry = mc.snapshot().entry("node:Person").unwrap().clone();
+
+    let table_key = "node:Human".to_string();
+    let table_path = table_path_for_table_key(&table_key).unwrap();
+    let dataset_uri = format!("{}/{}", uri, table_path);
+    let schema = Arc::new(Schema::new(vec![
+        Field::new("id", DataType::Utf8, false),
+        Field::new("name", DataType::Utf8, false),
+        Field::new("age", DataType::Int32, true),
+    ]));
+    let ds = crate::table_store::TableStore::create_empty_dataset(&dataset_uri, &schema)
+        .await
+        .unwrap();
+    let state = crate::table_store::TableStore::new(uri)
+        .table_state(&dataset_uri, &ds)
+        .await
+        .unwrap();
+
+    mc.commit_changes(&[
+        ManifestChange::RegisterTable(TableRegistration {
+            table_key: table_key.clone(),
+            table_path: table_path.clone(),
+        }),
+        ManifestChange::Update(SubTableUpdate {
+            table_key: table_key.clone(),
+            table_version: state.version,
+            table_branch: None,
+            row_count: state.row_count,
+            version_metadata: state.version_metadata,
+        }),
+        ManifestChange::Tombstone(TableTombstone {
+            table_key: "node:Person".to_string(),
+            tombstone_version: person_entry.table_version + 1,
+        }),
+    ])
+    .await
+    .unwrap();
+
+    let head = mc.snapshot();
+    assert!(head.entry("node:Human").is_some());
+    assert!(head.entry("node:Person").is_none());
+
+    let historical = ManifestCoordinator::snapshot_at(uri, None, before_version)
+        .await
+        .unwrap();
+    assert!(historical.entry("node:Person").is_some());
+    assert!(historical.entry("node:Human").is_none());
+}
+
 #[tokio::test]
 async fn test_snapshot_open_sub_table() {
     let dir = tempfile::tempdir().unwrap();
@@ -889,13 +946,16 @@ impl RecordingPublisher {
 
 #[async_trait]
 impl ManifestBatchPublisher for RecordingPublisher {
-    async fn publish(&self, updates: &[SubTableUpdate]) -> Result<Dataset> {
-        let requests: Vec<CreateTableVersionRequest> = updates
+    async fn publish(&self, changes: &[ManifestChange]) -> Result<Dataset> {
+        let requests: Vec<CreateTableVersionRequest> = changes
             .iter()
-            .map(SubTableUpdate::to_create_table_version_request)
+            .filter_map(|change| match change {
+                ManifestChange::Update(update) => Some(update.to_create_table_version_request()),
+                ManifestChange::RegisterTable(_) | ManifestChange::Tombstone(_) => None,
+            })
             .collect();
         self.requests.lock().await.extend_from_slice(&requests);
-        self.inner.publish_requests(&requests).await
+        self.inner.publish(changes).await
     }
 }
 
@@ -903,7 +963,7 @@ struct FailingPublisher;
 
 #[async_trait]
 impl ManifestBatchPublisher for FailingPublisher {
-    async fn publish(&self, _updates: &[SubTableUpdate]) -> Result<Dataset> {
+    async fn publish(&self, _changes: &[ManifestChange]) -> Result<Dataset> {
         Err(OmniError::manifest(
             "injected batch publisher failure".to_string(),
         ))

crates/omnigraph/src/db/mod.rs

@@ -8,6 +8,6 @@ mod schema_state;
 pub use commit_graph::GraphCommit;
 pub use graph_coordinator::{GraphCoordinator, ReadTarget, ResolvedTarget, SnapshotId};
 pub use manifest::{Snapshot, SubTableEntry, SubTableUpdate};
-pub use omnigraph::{MergeOutcome, Omnigraph};
+pub use omnigraph::{MergeOutcome, Omnigraph, SchemaApplyResult};
 pub(crate) use run_registry::is_internal_run_branch;
 pub use run_registry::{RunId, RunRecord, RunStatus};

crates/omnigraph/src/db/omnigraph.rs

@@ -5,7 +5,7 @@ use std::sync::Arc;
 use arrow_array::{
     Array, BinaryArray, BooleanArray, Date32Array, FixedSizeListArray, Float32Array, Float64Array,
     Int32Array, Int64Array, LargeBinaryArray, LargeListArray, LargeStringArray, ListArray,
-    RecordBatch, StringArray, StructArray, UInt32Array, UInt64Array,
+    RecordBatch, StringArray, StructArray, UInt32Array, UInt64Array, new_null_array,
 };
 use arrow_schema::{DataType, Field, Schema};
 use lance::Dataset;
@@ -17,7 +17,8 @@ use omnigraph_compiler::catalog::{Catalog, EdgeType, NodeType};
 use omnigraph_compiler::schema::parser::parse_schema;
 use omnigraph_compiler::types::ScalarType;
 use omnigraph_compiler::{
-    SchemaIR, SchemaMigrationPlan, build_catalog_from_ir, build_schema_ir, plan_schema_migration,
+    SchemaIR, SchemaMigrationPlan, SchemaMigrationStep, SchemaTypeKind, build_catalog_from_ir,
+    build_schema_ir, plan_schema_migration,
 };
 
 use crate::db::graph_coordinator::{GraphCoordinator, PublishedSnapshot};
@@ -28,7 +29,9 @@ use crate::storage::{StorageAdapter, join_uri, normalize_root_uri, storage_for_u
 use crate::table_store::TableStore;
 
 use super::commit_graph::GraphCommit;
-use super::manifest::Snapshot;
+use super::manifest::{
+    ManifestChange, Snapshot, TableRegistration, TableTombstone, table_path_for_table_key,
+};
 use super::schema_state::{
     SCHEMA_SOURCE_FILENAME, load_or_bootstrap_schema_contract, read_accepted_schema_ir,
     validate_schema_contract, write_schema_contract,
@@ -42,6 +45,14 @@ pub enum MergeOutcome {
     Merged,
 }
 
+#[derive(Debug, Clone)]
+pub struct SchemaApplyResult {
+    pub supported: bool,
+    pub applied: bool,
+    pub manifest_version: u64,
+    pub steps: Vec<SchemaMigrationStep>,
+}
+
 /// Top-level handle to an Omnigraph database.
 ///
 /// An Omnigraph is a Lance-native graph database with git-style branching.
@@ -160,6 +171,324 @@ impl Omnigraph {
             .map_err(|err| OmniError::manifest(err.to_string()))
     }
 
+    pub async fn apply_schema(&mut self, desired_schema_source: &str) -> Result<SchemaApplyResult> {
+        self.ensure_schema_state_valid().await?;
+        let branches = self.coordinator.all_branches().await?;
+        let public_non_main = branches
+            .iter()
+            .filter(|branch| branch.as_str() != "main")
+            .cloned()
+            .collect::<Vec<_>>();
+        if !public_non_main.is_empty() {
+            return Err(OmniError::manifest_conflict(format!(
+                "schema apply requires a repo with only main; found non-main branches: {}",
+                public_non_main.join(", ")
+            )));
+        }
+
+        let accepted_ir = read_accepted_schema_ir(self.uri(), Arc::clone(&self.storage)).await?;
+        let desired_ir = read_schema_ir_from_source(desired_schema_source)?;
+        let plan = plan_schema_migration(&accepted_ir, &desired_ir)
+            .map_err(|err| OmniError::manifest(err.to_string()))?;
+        if !plan.supported {
+            let reason = plan
+                .steps
+                .iter()
+                .find_map(|step| match step {
+                    SchemaMigrationStep::UnsupportedChange { reason, .. } => Some(reason.as_str()),
+                    _ => None,
+                })
+                .unwrap_or("unsupported schema migration plan");
+            return Err(OmniError::manifest(reason.to_string()));
+        }
+        if plan.steps.is_empty() {
+            return Ok(SchemaApplyResult {
+                supported: true,
+                applied: false,
+                manifest_version: self.version(),
+                steps: plan.steps,
+            });
+        }
+
+        let mut desired_catalog = build_catalog_from_ir(&desired_ir)?;
+        fixup_blob_schemas(&mut desired_catalog);
+
+        let snapshot = self.snapshot();
+        let mut added_tables = BTreeSet::new();
+        let mut renamed_tables = HashMap::new();
+        let mut rewritten_tables = BTreeSet::new();
+        let mut indexed_tables = BTreeSet::new();
+        let mut property_renames = HashMap::<String, HashMap<String, String>>::new();
+        let mut changed_edge_tables = false;
+
+        for step in &plan.steps {
+            match step {
+                SchemaMigrationStep::AddType { type_kind, name } => {
+                    let table_key = schema_table_key(*type_kind, name);
+                    if table_key.starts_with("edge:") {
+                        changed_edge_tables = true;
+                    }
+                    added_tables.insert(table_key);
+                }
+                SchemaMigrationStep::RenameType {
+                    type_kind,
+                    from,
+                    to,
+                } => {
+                    let source_key = schema_table_key(*type_kind, from);
+                    let target_key = schema_table_key(*type_kind, to);
+                    if source_key.starts_with("edge:") {
+                        changed_edge_tables = true;
+                    }
+                    renamed_tables.insert(target_key, source_key);
+                }
+                SchemaMigrationStep::AddProperty {
+                    type_kind,
+                    type_name,
+                    ..
+                } => {
+                    let table_key = schema_table_key(*type_kind, type_name);
+                    if table_key.starts_with("edge:") {
+                        changed_edge_tables = true;
+                    }
+                    rewritten_tables.insert(table_key);
+                }
+                SchemaMigrationStep::RenameProperty {
+                    type_kind,
+                    type_name,
+                    from,
+                    to,
+                } => {
+                    let table_key = schema_table_key(*type_kind, type_name);
+                    if table_key.starts_with("edge:") {
+                        changed_edge_tables = true;
+                    }
+                    rewritten_tables.insert(table_key.clone());
+                    property_renames
+                        .entry(table_key)
+                        .or_default()
+                        .insert(to.clone(), from.clone());
+                }
+                SchemaMigrationStep::AddConstraint {
+                    type_kind,
+                    type_name,
+                    ..
+                } => {
+                    indexed_tables.insert(schema_table_key(*type_kind, type_name));
+                }
+                SchemaMigrationStep::UpdateTypeMetadata { .. }
+                | SchemaMigrationStep::UpdatePropertyMetadata { .. } => {}
+                SchemaMigrationStep::UnsupportedChange { reason, .. } => {
+                    return Err(OmniError::manifest(reason.clone()));
+                }
+            }
+        }
+
+        let mut table_registrations = HashMap::<String, String>::new();
+        let mut table_updates = HashMap::<String, crate::db::SubTableUpdate>::new();
+        let mut table_tombstones = HashMap::<String, u64>::new();
+
+        for table_key in &added_tables {
+            let table_path = table_path_for_table_key(table_key)?;
+            let dataset_uri = self.table_store.dataset_uri(&table_path);
+            let schema = schema_for_table_key(&desired_catalog, table_key)?;
+            let mut ds = TableStore::create_empty_dataset(&dataset_uri, &schema).await?;
+            self.build_indices_on_dataset_for_catalog(&desired_catalog, table_key, &mut ds)
+                .await?;
+            let state = self.table_store.table_state(&dataset_uri, &ds).await?;
+            table_registrations.insert(table_key.clone(), table_path);
+            table_updates.insert(
+                table_key.clone(),
+                crate::db::SubTableUpdate {
+                    table_key: table_key.clone(),
+                    table_version: state.version,
+                    table_branch: None,
+                    row_count: state.row_count,
+                    version_metadata: state.version_metadata,
+                },
+            );
+        }
+
+        for (target_table_key, source_table_key) in &renamed_tables {
+            let source_entry = snapshot.entry(source_table_key).ok_or_else(|| {
+                OmniError::manifest(format!(
+                    "missing source table '{}' for schema rename",
+                    source_table_key
+                ))
+            })?;
+            let source_ds = snapshot.open(source_table_key).await?;
+            let batch = self
+                .batch_for_schema_apply_rewrite(
+                    &source_ds,
+                    source_table_key,
+                    &self.catalog,
+                    target_table_key,
+                    &desired_catalog,
+                    property_renames.get(target_table_key),
+                )
+                .await?;
+            let table_path = table_path_for_table_key(target_table_key)?;
+            let dataset_uri = self.table_store.dataset_uri(&table_path);
+            let mut target_ds = TableStore::write_dataset(&dataset_uri, batch).await?;
+            self.build_indices_on_dataset_for_catalog(
+                &desired_catalog,
+                target_table_key,
+                &mut target_ds,
+            )
+            .await?;
+            let state = self
+                .table_store
+                .table_state(&dataset_uri, &target_ds)
+                .await?;
+            table_registrations.insert(target_table_key.clone(), table_path);
+            table_updates.insert(
+                target_table_key.clone(),
+                crate::db::SubTableUpdate {
+                    table_key: target_table_key.clone(),
+                    table_version: state.version,
+                    table_branch: None,
+                    row_count: state.row_count,
+                    version_metadata: state.version_metadata,
+                },
+            );
+            table_tombstones.insert(
+                source_table_key.clone(),
+                source_entry.table_version.saturating_add(1),
+            );
+        }
+
+        for table_key in &rewritten_tables {
+            if added_tables.contains(table_key) || renamed_tables.contains_key(table_key) {
+                continue;
+            }
+            let entry = snapshot.entry(table_key).ok_or_else(|| {
+                OmniError::manifest(format!(
+                    "missing source table '{}' for schema apply",
+                    table_key
+                ))
+            })?;
+            let source_ds = snapshot.open(table_key).await?;
+            let batch = self
+                .batch_for_schema_apply_rewrite(
+                    &source_ds,
+                    table_key,
+                    &self.catalog,
+                    table_key,
+                    &desired_catalog,
+                    property_renames.get(table_key),
+                )
+                .await?;
+            let dataset_uri = self.table_store.dataset_uri(&entry.table_path);
+            let mut target_ds = TableStore::overwrite_dataset(&dataset_uri, batch).await?;
+            let mut state = self
+                .table_store
+                .table_state(&dataset_uri, &target_ds)
+                .await?;
+            if indexed_tables.contains(table_key) {
+                self.build_indices_on_dataset_for_catalog(
+                    &desired_catalog,
+                    table_key,
+                    &mut target_ds,
+                )
+                .await?;
+                state = self
+                    .table_store
+                    .table_state(&dataset_uri, &target_ds)
+                    .await?;
+            }
+            table_updates.insert(
+                table_key.clone(),
+                crate::db::SubTableUpdate {
+                    table_key: table_key.clone(),
+                    table_version: state.version,
+                    table_branch: None,
+                    row_count: state.row_count,
+                    version_metadata: state.version_metadata,
+                },
+            );
+        }
+
+        for table_key in &indexed_tables {
+            if added_tables.contains(table_key)
+                || renamed_tables.contains_key(table_key)
+                || rewritten_tables.contains(table_key)
+            {
+                continue;
+            }
+            let entry = snapshot.entry(table_key).ok_or_else(|| {
+                OmniError::manifest(format!(
+                    "missing table '{}' for schema index apply",
+                    table_key
+                ))
+            })?;
+            let dataset_uri = self.table_store.dataset_uri(&entry.table_path);
+            let mut ds = self
+                .table_store
+                .open_dataset_head_for_write(table_key, &dataset_uri, None)
+                .await?;
+            self.build_indices_on_dataset_for_catalog(&desired_catalog, table_key, &mut ds)
+                .await?;
+            let state = self.table_store.table_state(&dataset_uri, &ds).await?;
+            table_updates.insert(
+                table_key.clone(),
+                crate::db::SubTableUpdate {
+                    table_key: table_key.clone(),
+                    table_version: state.version,
+                    table_branch: None,
+                    row_count: state.row_count,
+                    version_metadata: state.version_metadata,
+                },
+            );
+        }
+
+        let mut manifest_changes = Vec::new();
+        for (table_key, table_path) in table_registrations {
+            manifest_changes.push(ManifestChange::RegisterTable(TableRegistration {
+                table_key,
+                table_path,
+            }));
+        }
+        for update in table_updates.into_values() {
+            manifest_changes.push(ManifestChange::Update(update));
+        }
+        for (table_key, tombstone_version) in table_tombstones {
+            manifest_changes.push(ManifestChange::Tombstone(TableTombstone {
+                table_key,
+                tombstone_version,
+            }));
+        }
+
+        let actor_id = self.current_audit_actor().map(str::to_string);
+        let PublishedSnapshot {
+            manifest_version,
+            _snapshot_id: _,
+        } = self
+            .coordinator
+            .commit_changes_with_actor(&manifest_changes, actor_id.as_deref())
+            .await?;
+
+        let schema_path = join_uri(&self.root_uri, SCHEMA_SOURCE_FILENAME);
+        self.storage
+            .write_text(&schema_path, desired_schema_source)
+            .await?;
+        write_schema_contract(&self.root_uri, self.storage.as_ref(), &desired_ir).await?;
+
+        self.catalog = desired_catalog;
+        self.schema_source = desired_schema_source.to_string();
+        self.coordinator.refresh().await?;
+        self.runtime_cache.invalidate_all().await;
+        if changed_edge_tables {
+            self.invalidate_graph_index().await;
+        }
+
+        Ok(SchemaApplyResult {
+            supported: true,
+            applied: true,
+            manifest_version,
+            steps: plan.steps,
+        })
+    }
+
     pub(crate) fn table_store(&self) -> &TableStore {
         &self.table_store
     }
@@ -1368,6 +1697,16 @@ impl Omnigraph {
         &self,
         table_key: &str,
         ds: &mut Dataset,
+    ) -> Result<()> {
+        self.build_indices_on_dataset_for_catalog(&self.catalog, table_key, ds)
+            .await
+    }
+
+    pub(crate) async fn build_indices_on_dataset_for_catalog(
+        &self,
+        catalog: &Catalog,
+        table_key: &str,
+        ds: &mut Dataset,
     ) -> Result<()> {
         if let Some(type_name) = table_key.strip_prefix("node:") {
             if !self.table_store.has_btree_index(ds, "id").await? {
@@ -1379,7 +1718,7 @@ impl Omnigraph {
                     })?;
             }
 
-            if let Some(node_type) = self.catalog.node_types.get(type_name) {
+            if let Some(node_type) = catalog.node_types.get(type_name) {
                 for index_cols in &node_type.indices {
                     if index_cols.len() != 1 {
                         continue;
@@ -1600,58 +1939,100 @@ impl Omnigraph {
         source_ds: &Dataset,
         table_key: &str,
     ) -> Result<RecordBatch> {
-        let target_schema = schema_for_table_key(self.catalog(), table_key)?;
-        let blob_properties = blob_properties_for_table_key(self.catalog(), table_key)?;
-        if blob_properties.is_empty() {
-            let batches = self.table_store().scan_batches(source_ds).await?;
-            return concat_or_empty_batches(target_schema, batches);
-        }
+        self.batch_for_schema_apply_rewrite(
+            source_ds,
+            table_key,
+            &self.catalog,
+            table_key,
+            &self.catalog,
+            None,
+        )
+        .await
+    }
 
-        let batches = self
-            .table_store()
-            .scan_with(source_ds, None, None, None, true, |_| Ok(()))
-            .await?;
-        let batch = concat_or_empty_batches(target_schema.clone(), batches)?;
-        if batch.num_rows() == 0 {
-            return Ok(batch);
+    async fn batch_for_schema_apply_rewrite(
+        &self,
+        source_ds: &Dataset,
+        source_table_key: &str,
+        source_catalog: &Catalog,
+        target_table_key: &str,
+        target_catalog: &Catalog,
+        property_renames: Option<&HashMap<String, String>>,
+    ) -> Result<RecordBatch> {
+        let target_schema = schema_for_table_key(target_catalog, target_table_key)?;
+        let source_blob_properties =
+            blob_properties_for_table_key(source_catalog, source_table_key)?;
+        let target_blob_properties =
+            blob_properties_for_table_key(target_catalog, target_table_key)?;
+        let needs_row_ids =
+            !source_blob_properties.is_empty() || !target_blob_properties.is_empty();
+        let batches = if needs_row_ids {
+            self.table_store()
+                .scan_with(source_ds, None, None, None, true, |_| Ok(()))
+                .await?
+        } else {
+            self.table_store().scan_batches(source_ds).await?
+        };
+        if batches.is_empty() {
+            return Ok(RecordBatch::new_empty(target_schema));
         }
+        let source_schema = batches[0].schema();
+        let batch = concat_or_empty_batches(source_schema, batches)?;
 
-        let row_ids = batch
-            .column_by_name("_rowid")
-            .and_then(|col| col.as_any().downcast_ref::<UInt64Array>())
-            .ok_or_else(|| {
-                OmniError::Lance(format!(
-                    "expected _rowid column when rewriting '{}'",
-                    table_key
-                ))
-            })?;
-        let row_ids: Vec<u64> = row_ids.values().iter().copied().collect();
+        let row_ids = if needs_row_ids {
+            Some(
+                batch
+                    .column_by_name("_rowid")
+                    .and_then(|col| col.as_any().downcast_ref::<UInt64Array>())
+                    .ok_or_else(|| {
+                        OmniError::Lance(format!(
+                            "expected _rowid column when rewriting '{}'",
+                            source_table_key
+                        ))
+                    })?
+                    .values()
+                    .iter()
+                    .copied()
+                    .collect::<Vec<_>>(),
+            )
+        } else {
+            None
+        };
 
         let mut columns = Vec::with_capacity(target_schema.fields().len());
         for field in target_schema.fields() {
-            if blob_properties.contains(field.name()) {
-                let descriptions = batch
-                    .column_by_name(field.name())
-                    .and_then(|col| col.as_any().downcast_ref::<StructArray>())
-                    .ok_or_else(|| {
-                        OmniError::Lance(format!(
-                            "expected blob descriptions for '{}.{}'",
-                            table_key,
-                            field.name()
-                        ))
-                    })?;
-                columns.push(
-                    self.rebuild_blob_column(source_ds, field.name(), descriptions, &row_ids)
-                        .await?,
-                );
+            let source_name = property_renames
+                .and_then(|renames| renames.get(field.name()))
+                .map(String::as_str)
+                .unwrap_or_else(|| field.name().as_str());
+            if let Some(column) = batch.column_by_name(source_name) {
+                if target_blob_properties.contains(field.name())
+                    && source_blob_properties.contains(source_name)
+                {
+                    let descriptions =
+                        column
+                            .as_any()
+                            .downcast_ref::<StructArray>()
+                            .ok_or_else(|| {
+                                OmniError::Lance(format!(
+                                    "expected blob descriptions for '{}.{}'",
+                                    source_table_key, source_name
+                                ))
+                            })?;
+                    let rebuilt = self
+                        .rebuild_blob_column(
+                            source_ds,
+                            source_name,
+                            descriptions,
+                            row_ids.as_deref().unwrap_or(&[]),
+                        )
+                        .await?;
+                    columns.push(rebuilt);
+                } else {
+                    columns.push(column.clone());
+                }
             } else {
-                columns.push(batch.column_by_name(field.name()).cloned().ok_or_else(|| {
-                    OmniError::Lance(format!(
-                        "missing column '{}.{}' in rewrite batch",
-                        table_key,
-                        field.name()
-                    ))
-                })?);
+                columns.push(new_null_array(field.data_type(), batch.num_rows()));
             }
         }
 
@@ -2130,6 +2511,14 @@ fn read_schema_ir_from_source(schema_source: &str) -> Result<SchemaIR> {
     build_schema_ir(&schema_ast).map_err(|err| OmniError::manifest(err.to_string()))
 }
 
+fn schema_table_key(type_kind: SchemaTypeKind, name: &str) -> String {
+    match type_kind {
+        SchemaTypeKind::Node => format!("node:{}", name),
+        SchemaTypeKind::Edge => format!("edge:{}", name),
+        SchemaTypeKind::Interface => unreachable!("interfaces do not map to tables"),
+    }
+}
+
 fn schema_for_table_key(catalog: &Catalog, table_key: &str) -> Result<Arc<Schema>> {
     if let Some(type_name) = table_key.strip_prefix("node:") {
         let node_type: &NodeType = catalog
@@ -2327,8 +2716,10 @@ fn json_value_from_array(array: &dyn Array, row: usize) -> Result<serde_json::Va
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::db::manifest::ManifestCoordinator;
     use async_trait::async_trait;
     use omnigraph_compiler::{SchemaMigrationStep, SchemaTypeKind};
+    use serde_json::Value;
     use std::fs;
     use std::sync::Mutex;
 
@@ -2621,6 +3012,182 @@ edge WorksAt: Person -> Company
         );
     }
 
+    async fn table_rows_json(db: &Omnigraph, table_key: &str) -> Vec<Value> {
+        let snapshot = db.snapshot();
+        let ds = snapshot.open(table_key).await.unwrap();
+        let batches = db.table_store().scan_batches(&ds).await.unwrap();
+        batches
+            .into_iter()
+            .flat_map(|batch| {
+                (0..batch.num_rows())
+                    .map(|row| record_batch_row_to_json(&batch, row).unwrap())
+                    .collect::<Vec<_>>()
+            })
+            .collect()
+    }
+
+    async fn seed_person_row(db: &mut Omnigraph, name: &str, age: Option<i32>) {
+        let (mut ds, full_path, table_branch) = db.open_for_mutation("node:Person").await.unwrap();
+        let schema: Arc<Schema> = Arc::new(ds.schema().into());
+        let columns: Vec<Arc<dyn Array>> = schema
+            .fields()
+            .iter()
+            .map(|field| match field.name().as_str() {
+                "id" => Arc::new(StringArray::from(vec![name])) as Arc<dyn Array>,
+                "name" => Arc::new(StringArray::from(vec![name])) as Arc<dyn Array>,
+                "age" => Arc::new(Int32Array::from(vec![age])) as Arc<dyn Array>,
+                _ => new_null_array(field.data_type(), 1),
+            })
+            .collect();
+        let batch = RecordBatch::try_new(Arc::clone(&schema), columns).unwrap();
+        let state = db
+            .table_store()
+            .append_batch(&full_path, &mut ds, batch)
+            .await
+            .unwrap();
+        db.commit_updates(&[crate::db::SubTableUpdate {
+            table_key: "node:Person".to_string(),
+            table_version: state.version,
+            table_branch,
+            row_count: state.row_count,
+            version_metadata: state.version_metadata,
+        }])
+        .await
+        .unwrap();
+    }
+
+    #[tokio::test]
+    async fn test_apply_schema_noop_returns_not_applied() {
+        let dir = tempfile::tempdir().unwrap();
+        let uri = dir.path().to_str().unwrap();
+        let mut db = Omnigraph::init(uri, TEST_SCHEMA).await.unwrap();
+
+        let result = db.apply_schema(TEST_SCHEMA).await.unwrap();
+        assert!(result.supported);
+        assert!(!result.applied);
+        assert!(result.steps.is_empty());
+    }
+
+    #[tokio::test]
+    async fn test_apply_schema_adds_nullable_property_and_preserves_rows() {
+        let dir = tempfile::tempdir().unwrap();
+        let uri = dir.path().to_str().unwrap();
+        let mut db = Omnigraph::init(uri, TEST_SCHEMA).await.unwrap();
+        seed_person_row(&mut db, "Alice", Some(30)).await;
+
+        let desired = TEST_SCHEMA.replace(
+            "    age: I32?\n}",
+            "    age: I32?\n    nickname: String?\n}",
+        );
+        let result = db.apply_schema(&desired).await.unwrap();
+        assert!(result.applied);
+
+        let reopened = Omnigraph::open(uri).await.unwrap();
+        let rows = table_rows_json(&reopened, "node:Person").await;
+        assert_eq!(rows.len(), 1);
+        assert_eq!(rows[0]["name"], "Alice");
+        assert_eq!(rows[0]["age"], 30);
+        assert!(rows[0]["nickname"].is_null());
+        assert!(
+            reopened.catalog().node_types["Person"]
+                .properties
+                .contains_key("nickname")
+        );
+        assert!(dir.path().join("_schema.pg").exists());
+    }
+
+    #[tokio::test]
+    async fn test_apply_schema_renames_property_and_preserves_values() {
+        let dir = tempfile::tempdir().unwrap();
+        let uri = dir.path().to_str().unwrap();
+        let mut db = Omnigraph::init(uri, TEST_SCHEMA).await.unwrap();
+        seed_person_row(&mut db, "Alice", Some(30)).await;
+
+        let desired = TEST_SCHEMA.replace(
+            "    age: I32?\n}",
+            "    years: I32? @rename_from(\"age\")\n}",
+        );
+        db.apply_schema(&desired).await.unwrap();
+
+        let reopened = Omnigraph::open(uri).await.unwrap();
+        let rows = table_rows_json(&reopened, "node:Person").await;
+        assert_eq!(rows[0]["name"], "Alice");
+        assert_eq!(rows[0]["years"], 30);
+        assert!(rows[0].get("age").is_none());
+    }
+
+    #[tokio::test]
+    async fn test_apply_schema_renames_type_and_preserves_historical_snapshot() {
+        let dir = tempfile::tempdir().unwrap();
+        let uri = dir.path().to_str().unwrap();
+        let mut db = Omnigraph::init(uri, TEST_SCHEMA).await.unwrap();
+        seed_person_row(&mut db, "Alice", Some(30)).await;
+        let before_version = db.snapshot().version();
+
+        let desired = TEST_SCHEMA
+            .replace("node Person {\n", "node Human @rename_from(\"Person\") {\n")
+            .replace("edge Knows: Person -> Person", "edge Knows: Human -> Human")
+            .replace(
+                "edge WorksAt: Person -> Company",
+                "edge WorksAt: Human -> Company",
+            );
+        db.apply_schema(&desired).await.unwrap();
+
+        let head = db.snapshot();
+        assert!(head.entry("node:Person").is_none());
+        assert!(head.entry("node:Human").is_some());
+        let historical = ManifestCoordinator::snapshot_at(uri, None, before_version)
+            .await
+            .unwrap();
+        assert!(historical.entry("node:Person").is_some());
+        assert!(historical.entry("node:Human").is_none());
+    }
+
+    #[tokio::test]
+    async fn test_apply_schema_rejects_when_non_main_branch_exists() {
+        let dir = tempfile::tempdir().unwrap();
+        let uri = dir.path().to_str().unwrap();
+        let mut db = Omnigraph::init(uri, TEST_SCHEMA).await.unwrap();
+        db.branch_create("feature").await.unwrap();
+
+        let desired = TEST_SCHEMA.replace(
+            "    age: I32?\n}",
+            "    age: I32?\n    nickname: String?\n}",
+        );
+        let err = db.apply_schema(&desired).await.unwrap_err();
+        assert!(
+            err.to_string()
+                .contains("schema apply requires a repo with only main")
+        );
+    }
+
+    #[tokio::test]
+    async fn test_apply_schema_adds_index_for_existing_property() {
+        let dir = tempfile::tempdir().unwrap();
+        let uri = dir.path().to_str().unwrap();
+        let mut db = Omnigraph::init(uri, TEST_SCHEMA).await.unwrap();
+
+        let desired = TEST_SCHEMA.replace("name: String @key", "name: String @key @index");
+        db.apply_schema(&desired).await.unwrap();
+
+        let snapshot = db.snapshot();
+        let ds = snapshot.open("node:Person").await.unwrap();
+        assert!(db.table_store().has_fts_index(&ds, "name").await.unwrap());
+    }
+
+    #[tokio::test]
+    async fn test_apply_schema_unsupported_plan_does_not_advance_manifest() {
+        let dir = tempfile::tempdir().unwrap();
+        let uri = dir.path().to_str().unwrap();
+        let mut db = Omnigraph::init(uri, TEST_SCHEMA).await.unwrap();
+        let before_version = db.snapshot().version();
+
+        let desired = TEST_SCHEMA.replace("age: I32?", "age: I64?");
+        let err = db.apply_schema(&desired).await.unwrap_err();
+        assert!(err.to_string().contains("changing property type"));
+        assert_eq!(db.snapshot().version(), before_version);
+    }
+
     #[tokio::test]
     async fn test_open_nonexistent_fails() {
         let result = Omnigraph::open("/tmp/nonexistent_omnigraph_test_xyz").await;

crates/omnigraph/src/table_store.rs

@@ -399,6 +399,20 @@ impl TableStore {
         self.append_batch(dataset_uri, ds, batch).await
     }
 
+    pub async fn overwrite_dataset(dataset_uri: &str, batch: RecordBatch) -> Result<Dataset> {
+        let reader = arrow_array::RecordBatchIterator::new(vec![Ok(batch.clone())], batch.schema());
+        let params = WriteParams {
+            mode: WriteMode::Overwrite,
+            enable_stable_row_ids: true,
+            data_storage_version: Some(LanceFileVersion::V2_2),
+            allow_external_blob_outside_bases: true,
+            ..Default::default()
+        };
+        Dataset::write(reader, dataset_uri, Some(params))
+            .await
+            .map_err(|e| OmniError::Lance(e.to_string()))
+    }
+
     pub async fn merge_insert_batch(
         &self,
         dataset_uri: &str,

docs/cli.md

@@ -48,6 +48,7 @@ and configure the matching `bearer_token_env` in `omnigraph.yaml`.
 
 ```bash
 omnigraph schema plan --schema ./next.pg ./repo.omni --json
+omnigraph schema apply --schema ./next.pg ./repo.omni --json
 omnigraph policy validate --config ./omnigraph.yaml
 omnigraph policy test --config ./omnigraph.yaml
 omnigraph policy explain --config ./omnigraph.yaml --actor act-alice --action read --branch main
@@ -87,3 +88,6 @@ The config file can also define:
 - auth env files
 - query aliases for common read and change commands
 - `policy.file` for Cedar authorization rules
+
+When policy is enabled, `schema apply` is authorized through the
+`schema_apply` action and is typically limited to admins on protected `main`.