mcp-think

A remote MCP server for structured sequential thinking, built for Cloudflare Workers.

Architecture

• Cloudflare Worker exposes /mcp over Streamable HTTP.

• MCP SDK v2 defines the tools.

• Durable Objects + SQLite persist each sequence.

• A sequence is addressed by an explicit sequenceId; MCP protocol sessions do not carry application state.

This design follows the current Cloudflare guidance: new MCP servers use the v2/stateless handler, while application state for multi-step workflows lives behind an explicit Durable Object boundary. McpAgent is deprecated and is intentionally not used here.

Related MCP server: handoff-mcp

Tools

start_sequence

Creates a sequence and returns a sequenceId.

add_step

Adds a structured step. Use this for summaries, assumptions, evidence, hypotheses, or decisions. The server is not intended to expose or store hidden chain-of-thought.

revise_step

Creates a new revision of a previous step while preserving the original record.

get_sequence

Returns the sequence metadata and all stored steps.

finish_sequence

Stores the final conclusion and marks the sequence as completed.

reset_sequence

Deletes the stored sequence data.

Local development

npm install
npm run typecheck
npm run dev

The local MCP endpoint is:

http://localhost:8787/mcp

Health check:

http://localhost:8787/health

Deploy

Authenticate Wrangler with your Cloudflare account and run:

npm run deploy

Cloudflare will provision the SQLite-backed Durable Object from the migration in wrangler.jsonc.

Example flow

start_sequence(goal)
      ↓
sequenceId
      ↓
add_step(sequenceId, ...)
      ↓
add_step(sequenceId, ...)
      ↓
revise_step(sequenceId, stepId, ...)
      ↓
get_sequence(sequenceId)
      ↓
finish_sequence(sequenceId, conclusion)

Security roadmap

The MVP intentionally has no authentication. Before exposing the endpoint publicly, add OAuth or another authentication layer and bind sequence ownership to the authenticated principal. Cloudflare's MCP guidance also recommends explicit Host/Origin validation and authentication rather than treating CORS as an auth mechanism.