Add MCP workflow telemetry for AI plugins

[glendaviesnz]

Fixes: https://linear.app/a8c/issue/STU-1530/add-telemetry-for-external-agents

Summary

This adds plugin-aware MCP workflow telemetry for Studio's AI integrations. This is needed so we can track usage of the Studio MCP by external agents, eg. https://github.com/Automattic/build-with-wordpress

Changes include:

• adding a hidden studio mcp --telemetry-group <group> option so different AI plugin integrations can identify themselves when they launch the Studio MCP server
• extending the Studio CLI bump-stat types to allow plugin telemetry groups and workflow-stage stats
• adding a new record_workflow_event MCP tool that records workflow milestones like theme-build-started, theme-build-completed, and theme-build-failed
• threading the configured telemetry group through the MCP startup path so the tool can record events without the caller having to pass the plugin identity every time
• updating the Studio AI UI/system prompt metadata so the new tool is surfaced cleanly in the built-in assistant
• adding targeted MCP tool tests for configured and unconfigured telemetry behavior

This is designed to support plugin-grouped telemetry such as:

• codex-plugin + theme-build-started
• claude-code-plugin + theme-build-completed

Testing

Automated

• npm test -- apps/cli/ai/tests/tools.test.ts

Manual

1. Launch Studio MCP with a telemetry group, for example:
   • studio mcp --telemetry-group codex-plugin
2. Connect an MCP client and confirm the record_workflow_event tool is available.
3. Call the tool with:
   • workflow: theme-build
   • stage: started
4. Confirm the tool returns a success message showing the plugin group and stat name.
5. Repeat with completed and failed stages and with another workflow such as site-build.
6. Launch studio mcp without --telemetry-group and confirm the tool reports that workflow telemetry was skipped because no plugin group was configured.

Notes

• I also ran npx tsc -p apps/cli/tsconfig.json --noEmit, but it still reports an existing unrelated memfs test typing issue in apps/cli/lib/tests/snapshots.test.ts.

[wpmobilebot]

📊 Performance Test Results

Comparing 85e2639 vs trunk

app-size

Metric	trunk	85e2639	Diff	Change
App Size (Mac)	1252.07 MB	1252.00 MB	0.08 MB	⚪ 0.0%

site-editor

Metric	trunk	85e2639	Diff	Change
load	1945 ms	1944 ms	1 ms	⚪ 0.0%

site-startup

Metric	trunk	85e2639	Diff	Change
siteCreation	9108 ms	8180 ms	928 ms	🟢 -10.2%
siteStartup	4175 ms	4840 ms	+665 ms	🔴 15.9%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)

[sejas]

Hi @glendaviesnz , does this PR relate to any Linear issue? is necessary for Telex? Thank you!
When ready feel free to assign me or YOLO team as reviewer. If it's still in progress it would be great to move it as a draft.

[glendaviesnz]

Hi @glendaviesnz , does this PR relate to any Linear issue? is necessary for Telex? Thank you! When ready feel free to assign me or YOLO team as reviewer. If it's still in progress it would be great to move it as a draft.

Sorry @sejas, meant to add more detail, done now with a link to Linear issue. I am very open to alternative approaches to this, just let me know if you see a better way to handle it.