feat(telemetry): include error details for failures (#254)

docs-site/content/docs/community/telemetry.mdx

@@ -25,10 +25,11 @@ Use any of these mechanisms to disable telemetry:
 
 ## What we collect
 
-High-level signals only: which commands run, how long they take, whether they
+High-level signals: which commands run, how long they take, whether they
 succeed or fail, and basic environment metadata (CLI version, Node version, OS
-platform). For project-level analysis, **ktx** sends a salted hash of the
-project directory — never the raw path.
+platform). When an operation fails, we also include diagnostic detail about the
+error so we can debug it. For project-level analysis, **ktx** sends a salted
+hash of the project directory to group events.
 
 When an agent reaches **ktx** through MCP, we also record the connecting client
 tool's self-reported name and version (for example Claude Desktop, Cursor, or
@@ -37,11 +38,14 @@ tool, never you or your data.
 
 ## What we never collect
 
-- File paths, hostnames, environment variable values, or command arguments
-- `ktx.yaml` contents, connection passwords, API keys, or tokens
-- Schema names, table names, column names, SQL text, or query results
-- Error messages or stack traces
-- Git remote URLs, Git user email, OS user, or hostname
+We build telemetry around counts and coarse signals, not the contents of your
+data or configuration. We don't deliberately collect your `ktx.yaml`, query
+results, passwords, API keys, or access tokens.
+
+The one place environment-specific text can appear is failure diagnostics: when
+an operation errors, the detail we record is the error as your tools reported
+it, which can include identifiers from your setup. If you'd rather send nothing
+at all, turn telemetry off using any of the options above.
 
 ## Storage and retention