[integrations] update_thought MCP with if_unchanged_since

[txcfi-scott]

What it does

Adds a standalone MCP Edge Function that exposes a single new tool: update_thought(id, content?, metadata_patch?, if_unchanged_since?).

The core server/index.ts is curated and does not expose an update path. This integration adds one without touching the core server — it deploys as its own Supabase Edge Function and is registered as a separate custom connector alongside the main Open Brain connector.

Why it matters

Once more than one agent writes to the same Open Brain (Claude Desktop + Codex + a background worker, or a shared brain across teammates), last-write-wins silently drops concurrent edits. Optimistic concurrency is the cheapest fix:

1. Caller reads a thought, notes its updated_at (T0).
2. Caller issues update_thought with if_unchanged_since = T0.
3. If the stored updated_at is still <= T0, the update proceeds. If another writer has advanced it past T0, the server rejects with STALE_READ and the caller can re-fetch and retry.

Omitting if_unchanged_since keeps the old last-write-wins behaviour — fully backward compatible.

What it requires

• Working Open Brain setup (the thoughts table + the update_updated_at trigger from the getting-started guide).
• Supabase CLI for deployment.
• OpenRouter API key — only exercised when callers pass content (re-embedding path).

Tested

Deployed against a live Supabase Open Brain instance. Verified:

• metadata_patch-only updates succeed without an OpenRouter key.
• content updates regenerate the embedding and the row's updated_at advances.
• Two concurrent writers, the second passing if_unchanged_since from its pre-mutation read, receive a clear STALE_READ error once the first writer has committed.

Files touched

Only integrations/update-thought-mcp/ — stays within the contribution scope check.

Attribution

Adapted from a multi-participant capture design used across live Claude / ChatGPT / Codex sessions. Released here as a standalone integration so any Open Brain user can opt in without modifying the core server.

[github-actions]

Hey @txcfi-scott — welcome to Open Brain Source! 👋

Thanks for submitting your first PR. The automated review will run shortly and check things like metadata, folder structure, and README completeness. If anything needs fixing, the review comment will tell you exactly what.

Once the automated checks pass, a human admin will review for quality and clarity. Expect a response within a few days.

If you have questions, check out CONTRIBUTING.md or open an issue.