docs(mcp): document add_to_thread and thread tools

[devin-ai-integration]

Summary

Syncs Consensus-NLP/common@95af37b1e9a71816e0a0c7592d8aec988f5edb50 (CON-5230, #8237), which adds the add_to_thread MCP tool and makes the thread tool family externally visible.

Adds a Research thread tools section to consensus-mcp.mdx covering:

• create_thread — start a research thread and dispatch the agent.
• add_to_thread — append a genuine follow-up to an existing thread by thread_id.
• Shared dispatch response fields (thread_id, interaction_id, status, url, poll_after_seconds, max_wait_seconds, etc.).
• mode semantics: pro (default) or deep (requires a signed-in paid caller).
• Optional filters (same keys as search) and attachments shape.
• title is optional on add_to_thread and is used only for the deep-link slug.

No openapi.json changes are needed because the commit only changed MCP tool definitions; no public REST endpoint, schema, or rate limit was modified.

Link to Devin session: https://app.devin.ai/sessions/c6af4a063354487bb3e66c3c3484a314
Open in Devin Desktop: https://app.devin.ai/desktop/session/c6af4a063354487bb3e66c3c3484a314?variant=devin
Requested by: @aakashadesara

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment, CI, and merge conflict monitoring

[mintlify]

Preview deployment for your docs. Learn more about Mintlify Previews.

Project	Status	Preview	Updated (UTC)
consensus	🟢 Ready	View Preview	Aug 27, 2026, 4:47 AM

💡 Tip: Enable Workflows to automatically generate PRs for you.