feat: query_policy semantic-layer-only restricts agents to predefined semantic-layer measures (#334)

* feat(sl): add predefined_measures_only guard to semantic query planning

SemanticQuery gains a predefined_measures_only flag; the planner rejects
any measure resolved with Provenance.COMPOSED (runtime aggregate
expressions and query-time derivations) while predefined measures,
predefined derived chains, dimensions, filters, and segments pass.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* feat(config): add per-connection query_policy to warehouse connections

query_policy: semantic-layer-only | read-only-sql (default) on the
warehouse connection schema, plus a policy module with the raw-SQL
guard, federated member restriction lookup, and the project-level
predicate used to gate sql_execution registration.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* feat(cli): enforce query_policy on raw SQL through one shared executor

ktx sql and the MCP sql_execution tool now share executeProjectRawSql
(resolve, policy check, read-only validation, execute), collapsing
their duplicated validate-then-execute paths. Restricted connections
are rejected before validation; federated raw SQL is rejected when any
member is restricted. sql_execution is not registered when every SQL
connection is restricted, and connection_list marks restricted
connections so agents route to sl_query. executeProjectReadOnlySql
stays generic for ktx-internal SQL (scan, ingest, SL-generated).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* feat(sl): compile queries with predefined_measures_only from query_policy

compileLocalSlQuery injects the flag from the connection's query_policy,
never from caller input, covering both ktx sl query and the MCP
sl_query tool through the daemon compile path.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* docs: document query_policy semantic-layer-only

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(sl): close semantic-layer-only bypasses via filters and federated hint

The predefined_measures_only guard only inspected query.measures, so a
composed aggregate written into `filters` slipped through _classify_filters
into a HAVING clause untouched — letting a restricted agent evaluate
arbitrary aggregates (e.g. threshold-probing `sum(x) BETWEEN a AND b`).
Reject filter clauses that compose an aggregate function; a HAVING that
compares a predefined measure by name (`orders.revenue > 100`) still works.

Also make the federated sl_query error policy-aware: when a member is
restricted, raw federated SQL is disabled too, so stop directing the agent
to `ktx sql -c _ktx_federated` / sql_execution (a guaranteed failure) and
point to per-connection semantic-layer queries instead.

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: Andrey Avtomonov <andreybavt@gmail.com>

packages/cli/test/context/connections/project-sql-executor.test.ts

@@ -1,10 +1,14 @@
 import { describe, expect, it, vi } from 'vitest';
 import type { executeFederatedQuery } from '../../../src/connectors/duckdb/federated-executor.js';
-import { executeProjectReadOnlySql } from '../../../src/context/connections/project-sql-executor.js';
+import { executeProjectRawSql, executeProjectReadOnlySql } from '../../../src/context/connections/project-sql-executor.js';
 import type { KtxLocalProject } from '../../../src/context/project/project.js';
 import type { KtxScanConnector } from '../../../src/context/scan/types.js';
+import type { SqlAnalysisPort } from '../../../src/context/sql-analysis/ports.js';
+import { KtxQueryError } from '../../../src/errors.js';
 
-function fakeProject(connections: Record<string, { driver: string }>): KtxLocalProject {
+function fakeProject(
+  connections: Record<string, { driver: string; query_policy?: 'semantic-layer-only' }>,
+): KtxLocalProject {
   return {
     projectDir: '/tmp/proj',
     configPath: '/tmp/proj/ktx.yaml',
@@ -114,3 +118,97 @@ describe('executeProjectReadOnlySql headerTypes', () => {
     expect(result.headerTypes).toEqual(['INTEGER']);
   });
 });
+
+function fakeSqlAnalysis(validation: { ok: boolean; error: string | null }): SqlAnalysisPort {
+  return {
+    analyzeForFingerprint: vi.fn(),
+    analyzeBatch: vi.fn(),
+    validateReadOnly: vi.fn(async () => validation),
+  } as unknown as SqlAnalysisPort;
+}
+
+describe('executeProjectRawSql', () => {
+  it('validates then executes raw SQL on an unrestricted connection', async () => {
+    const project = fakeProject({ pg: { driver: 'postgres' } });
+    const sqlAnalysis = fakeSqlAnalysis({ ok: true, error: null });
+    const connector = connectorReturning({
+      headers: ['id'],
+      rows: [[1]],
+      totalRows: 1,
+      rowCount: 1,
+    });
+
+    const result = await executeProjectRawSql({
+      project,
+      connectionId: 'pg',
+      sql: 'SELECT id FROM orders',
+      maxRows: 25,
+      sqlAnalysis,
+      createConnector: () => connector,
+      runId: 'test-raw-sql',
+    });
+
+    expect(result.rows).toEqual([[1]]);
+    expect(sqlAnalysis.validateReadOnly).toHaveBeenCalledWith('SELECT id FROM orders', 'postgres');
+  });
+
+  it('rejects a restricted connection before validation or execution', async () => {
+    const project = fakeProject({ pg: { driver: 'postgres', query_policy: 'semantic-layer-only' } });
+    const sqlAnalysis = fakeSqlAnalysis({ ok: true, error: null });
+    const createConnector = vi.fn();
+
+    const execution = executeProjectRawSql({
+      project,
+      connectionId: 'pg',
+      sql: 'SELECT 1',
+      maxRows: 25,
+      sqlAnalysis,
+      createConnector: createConnector as never,
+      runId: 'test-raw-sql',
+    });
+    await expect(execution).rejects.toBeInstanceOf(KtxQueryError);
+    await expect(execution).rejects.toThrow(/query_policy: semantic-layer-only/);
+    expect(sqlAnalysis.validateReadOnly).not.toHaveBeenCalled();
+    expect(createConnector).not.toHaveBeenCalled();
+  });
+
+  it('rejects federated raw SQL when a member connection is restricted', async () => {
+    const project = fakeProject({
+      pg: { driver: 'postgres', query_policy: 'semantic-layer-only' },
+      lite: { driver: 'sqlite' },
+    });
+    const executeFederated = vi.fn();
+
+    await expect(
+      executeProjectRawSql({
+        project,
+        connectionId: '_ktx_federated',
+        sql: 'SELECT 1',
+        maxRows: 25,
+        sqlAnalysis: fakeSqlAnalysis({ ok: true, error: null }),
+        createConnector: vi.fn() as never,
+        executeFederated: executeFederated as never,
+        runId: 'test-raw-sql',
+      }),
+    ).rejects.toThrow(/"pg"/);
+    expect(executeFederated).not.toHaveBeenCalled();
+  });
+
+  it('classifies a read-only validation failure as an expected query error', async () => {
+    const project = fakeProject({ pg: { driver: 'postgres' } });
+    const createConnector = vi.fn();
+
+    const execution = executeProjectRawSql({
+      project,
+      connectionId: 'pg',
+      sql: 'DROP TABLE orders',
+      maxRows: 25,
+      sqlAnalysis: fakeSqlAnalysis({ ok: false, error: 'SQL is not read-only: DROP.' }),
+      createConnector: createConnector as never,
+      runId: 'test-raw-sql',
+    });
+    await expect(execution).rejects.toBeInstanceOf(KtxQueryError);
+    await expect(execution).rejects.toThrow('SQL is not read-only: DROP.');
+    expect(createConnector).not.toHaveBeenCalled();
+  });
+});

packages/cli/test/context/connections/query-policy.test.ts

@@ -0,0 +1,144 @@
+import { describe, expect, it } from 'vitest';
+import {
+  assertRawSqlAllowed,
+  connectionQueryPolicy,
+  projectAllowsRawSql,
+  restrictedFederatedMemberIds,
+} from '../../../src/context/connections/query-policy.js';
+import { parseKtxProjectConfig } from '../../../src/context/project/config.js';
+import { KtxQueryError } from '../../../src/errors.js';
+
+const PROJECT_DIR = '/tmp/proj';
+
+function config(yaml: string) {
+  return parseKtxProjectConfig(yaml);
+}
+
+describe('connectionQueryPolicy', () => {
+  it('defaults to read-only-sql when the field is absent or the connection is unknown', () => {
+    const parsed = config(`
+connections:
+  warehouse:
+    driver: sqlite
+    url: file:warehouse.db
+`);
+    expect(connectionQueryPolicy(parsed.connections.warehouse)).toBe('read-only-sql');
+    expect(connectionQueryPolicy(undefined)).toBe('read-only-sql');
+  });
+
+  it('reads semantic-layer-only from ktx.yaml', () => {
+    const parsed = config(`
+connections:
+  warehouse:
+    driver: snowflake
+    url: env:SNOWFLAKE_URL
+    query_policy: semantic-layer-only
+`);
+    expect(connectionQueryPolicy(parsed.connections.warehouse)).toBe('semantic-layer-only');
+  });
+
+  it('rejects unknown query_policy values at config parse time', () => {
+    expect(() =>
+      config(`
+connections:
+  warehouse:
+    driver: sqlite
+    url: file:warehouse.db
+    query_policy: everything-goes
+`),
+    ).toThrow();
+  });
+});
+
+describe('assertRawSqlAllowed', () => {
+  it('allows raw SQL on an unrestricted connection', () => {
+    const parsed = config(`
+connections:
+  warehouse:
+    driver: sqlite
+    url: file:warehouse.db
+`);
+    expect(() => assertRawSqlAllowed(parsed, PROJECT_DIR, 'warehouse')).not.toThrow();
+  });
+
+  it('rejects raw SQL on a restricted connection with an expected error naming the policy', () => {
+    const parsed = config(`
+connections:
+  warehouse:
+    driver: sqlite
+    url: file:warehouse.db
+    query_policy: semantic-layer-only
+`);
+    expect(() => assertRawSqlAllowed(parsed, PROJECT_DIR, 'warehouse')).toThrow(KtxQueryError);
+    expect(() => assertRawSqlAllowed(parsed, PROJECT_DIR, 'warehouse')).toThrow(
+      /query_policy: semantic-layer-only/,
+    );
+  });
+
+  it('rejects federated raw SQL when any member connection is restricted', () => {
+    const parsed = config(`
+connections:
+  sales:
+    driver: sqlite
+    url: file:sales.db
+    query_policy: semantic-layer-only
+  events:
+    driver: sqlite
+    url: file:events.db
+`);
+    expect(restrictedFederatedMemberIds(parsed, PROJECT_DIR)).toEqual(['sales']);
+    expect(() => assertRawSqlAllowed(parsed, PROJECT_DIR, '_ktx_federated')).toThrow(/"sales"/);
+  });
+
+  it('allows federated raw SQL when no member is restricted', () => {
+    const parsed = config(`
+connections:
+  sales:
+    driver: sqlite
+    url: file:sales.db
+  events:
+    driver: sqlite
+    url: file:events.db
+`);
+    expect(restrictedFederatedMemberIds(parsed, PROJECT_DIR)).toEqual([]);
+    expect(() => assertRawSqlAllowed(parsed, PROJECT_DIR, '_ktx_federated')).not.toThrow();
+  });
+});
+
+describe('projectAllowsRawSql', () => {
+  it('is true when at least one SQL connection is unrestricted', () => {
+    const parsed = config(`
+connections:
+  finance:
+    driver: postgres
+    url: env:FINANCE_URL
+    query_policy: semantic-layer-only
+  warehouse:
+    driver: sqlite
+    url: file:warehouse.db
+`);
+    expect(projectAllowsRawSql(parsed)).toBe(true);
+  });
+
+  it('is false when every SQL connection is restricted', () => {
+    const parsed = config(`
+connections:
+  finance:
+    driver: postgres
+    url: env:FINANCE_URL
+    query_policy: semantic-layer-only
+`);
+    expect(projectAllowsRawSql(parsed)).toBe(false);
+  });
+
+  it('is true for projects with no SQL-queryable connections', () => {
+    const parsed = config(`
+connections:
+  docs:
+    driver: mongodb
+    url: mongodb://localhost:27017/app
+`);
+    expect(projectAllowsRawSql(parsed)).toBe(true);
+    expect(projectAllowsRawSql(config('connections: {}'))).toBe(true);
+  });
+});

packages/cli/test/context/mcp/__snapshots__/mcp-tools-list.json

@@ -33,6 +33,10 @@
               },
               "hint": {
                 "type": "string"
+              },
+              "queryPolicy": {
+                "type": "string",
+                "const": "semantic-layer-only"
               }
             },
             "required": [

packages/cli/test/context/mcp/local-project-ports.test.ts

@@ -247,6 +247,80 @@ describe('createLocalProjectMcpContextPorts', () => {
     expect(connector.cleanup).toHaveBeenCalled();
   });
 
+  it('omits sql_execution when every SQL connection is semantic-layer-only', async () => {
+    const project = await initKtxProject({ projectDir: tempDir });
+    project.config.connections.warehouse = {
+      driver: 'postgres',
+      url: 'env:DATABASE_URL',
+      query_policy: 'semantic-layer-only',
+    };
+    const ports = createLocalProjectMcpContextPorts(project, {
+      sqlAnalysis: {
+        analyzeForFingerprint: vi.fn(),
+        analyzeBatch: vi.fn(),
+        validateReadOnly: vi.fn(async () => ({ ok: true, error: null })),
+      },
+      localScan: { createConnector: vi.fn(async () => testConnector()) },
+      embeddingService: null,
+    });
+
+    expect(ports.sqlExecution).toBeUndefined();
+  });
+
+  it('keeps sql_execution in mixed projects but rejects restricted connections and flags them in connection_list', async () => {
+    const project = await initKtxProject({ projectDir: tempDir });
+    project.config.connections.warehouse = {
+      driver: 'postgres',
+      url: 'env:DATABASE_URL',
+    };
+    project.config.connections.finance = {
+      driver: 'postgres',
+      url: 'env:FINANCE_URL',
+      query_policy: 'semantic-layer-only',
+    };
+    const createConnector = vi.fn(async () => testConnector());
+    const sqlAnalysis = {
+      analyzeForFingerprint: vi.fn(),
+      analyzeBatch: vi.fn(),
+      validateReadOnly: vi.fn(async () => ({ ok: true, error: null })),
+    };
+    const ports = createLocalProjectMcpContextPorts(project, {
+      sqlAnalysis,
+      localScan: { createConnector },
+      embeddingService: null,
+    });
+
+    expect(ports.sqlExecution).toBeDefined();
+    const execution = ports.sqlExecution?.execute({
+      connectionId: 'finance',
+      sql: 'select 1',
+      maxRows: 5,
+    });
+    await expect(execution).rejects.toBeInstanceOf(KtxQueryError);
+    await expect(execution).rejects.toThrow(/query_policy: semantic-layer-only/);
+    expect(sqlAnalysis.validateReadOnly).not.toHaveBeenCalled();
+    expect(createConnector).not.toHaveBeenCalled();
+
+    // Both postgres members federate, so the restricted member also blocks federated raw SQL.
+    await expect(
+      ports.sqlExecution?.execute({ connectionId: '_ktx_federated', sql: 'select 1', maxRows: 5 }),
+    ).rejects.toThrow(/"finance"/);
+
+    await expect(ports.connections?.list()).resolves.toEqual([
+      expect.objectContaining({
+        id: 'finance',
+        queryPolicy: 'semantic-layer-only',
+        hint: expect.stringContaining('sl_query'),
+      }),
+      expect.objectContaining({ id: 'warehouse' }),
+      expect.objectContaining({
+        id: '_ktx_federated',
+        queryPolicy: 'semantic-layer-only',
+        hint: expect.stringContaining('finance'),
+      }),
+    ]);
+  });
+
   it('rejects sql_execution against an unconfigured connection with an actionable expected error', async () => {
     const project = await initKtxProject({ projectDir: tempDir });
     project.config.connections.warehouse = {

packages/cli/test/context/sl/local-query.test.ts

@@ -3,6 +3,7 @@ import { tmpdir } from 'node:os';
 import { join } from 'node:path';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import type { KtxSemanticLayerComputePort } from '../../../src/context/daemon/semantic-layer-compute.js';
+import { FEDERATED_CONNECTION_ID } from '../../../src/context/connections/federation.js';
 import { initKtxProject, type KtxLocalProject } from '../../../src/context/project/project.js';
 import { compileLocalSlQuery } from '../../../src/context/sl/local-query.js';
 
@@ -67,6 +68,59 @@ grain: []
     await rm(tempDir, { recursive: true, force: true });
   });
 
+  it('injects predefined_measures_only when the connection query_policy is semantic-layer-only', async () => {
+    project.config.connections.warehouse = { driver: 'postgres', query_policy: 'semantic-layer-only' };
+
+    await compileLocalSlQuery(project, {
+      connectionId: 'warehouse',
+      query: { measures: ['orders.order_count'], dimensions: [], limit: 10 },
+      compute,
+    });
+
+    expect(compute.query).toHaveBeenCalledWith(
+      expect.objectContaining({
+        query: expect.objectContaining({ predefined_measures_only: true }),
+      }),
+    );
+  });
+
+  it('rejects a federated sl_query, pointing to per-connection SL when a member is restricted', async () => {
+    project.config.connections.warehouse = { driver: 'postgres', query_policy: 'semantic-layer-only' };
+    project.config.connections.analytics = { driver: 'postgres' };
+
+    let message = '';
+    try {
+      await compileLocalSlQuery(project, {
+        connectionId: FEDERATED_CONNECTION_ID,
+        query: { measures: ['orders.order_count'], dimensions: [] },
+        compute,
+      });
+      throw new Error('expected compileLocalSlQuery to reject');
+    } catch (e) {
+      message = (e as Error).message;
+    }
+
+    expect(message).toContain("member connection(s) 'warehouse'");
+    expect(message).toContain('query_policy: semantic-layer-only');
+    // Must not send the agent down the raw-SQL path that assertRawSqlAllowed rejects.
+    expect(message).not.toContain(`ktx sql -c ${FEDERATED_CONNECTION_ID}`);
+    expect(message).not.toContain('sql_execution');
+    expect(compute.query).not.toHaveBeenCalled();
+  });
+
+  it('rejects a federated sl_query, pointing to raw federated SQL when no member is restricted', async () => {
+    project.config.connections.analytics = { driver: 'postgres' };
+
+    await expect(
+      compileLocalSlQuery(project, {
+        connectionId: FEDERATED_CONNECTION_ID,
+        query: { measures: ['orders.order_count'], dimensions: [] },
+        compute,
+      }),
+    ).rejects.toThrow(`ktx sql -c ${FEDERATED_CONNECTION_ID}`);
+    expect(compute.query).not.toHaveBeenCalled();
+  });
+
   it('refuses a non-SQL (context-only) connection instead of compiling it as Postgres', async () => {
     project.config.connections['mongo-prod'] = { driver: 'mongodb', url: 'mongodb://localhost:27017/app' };
     await expect(
@@ -109,6 +163,7 @@ grain: []
         measures: ['orders.order_count'],
         dimensions: ['orders.status'],
         limit: 25,
+        predefined_measures_only: false,
       },
     });
     expect(result).toEqual({
@@ -190,6 +245,7 @@ grain: []
       query: {
         measures: ['sum(payments.amount)'],
         dimensions: [],
+        predefined_measures_only: false,
       },
     });
   });