Model Context Protocol / tool surfaces
These projects turn software into explicit tools for agents. The transport, authority boundary, storage model, and failure state are part of the product—not plumbing to hide.
Remote Streamable HTTP server
The canonical 73-tool TurtlePen engine over public Streamable HTTP. Each MCP session retains one active document and a confined artifact workspace across requests.
73 tools · v0.3.2 · D1 session index · R2 state + artifacts
SourceLocal stdio server
A GUI-installed MCP server that gives ChatGPT constrained local file access without pretending a remote service can see the user’s machine.
Python · MIT · explicit local boundary
SourceSource-intelligence research
Earlier Brainn.dev research into routing framework questions through official source registries, separating discovery from execution, and keeping approval explicit.
Package and policy lineage in the prior Brainn.dev repository
SourceHosted TurtlePen boundary
Brainn.dev vendors the same source used by the local stdio server and calls its live createTools(session) registry. The web adapter owns transport and persistence only; it does not reimplement measurement, validation, or SVG rendering.
Live service contract
POST JSON-RPC with SSE responses and MCP protocol 2025-06-18.
Reuse Mcp-Session-Id; one isolated active document persists across calls.
Rate, payload, history, and storage caps refuse by name; nothing is truncated.
Session files and inline SVG renders stay in expiring, versioned R2 storage.
Connect to the canonical TurtlePen server.
Add https://brainn.dev/api/mcp/turtlepen to a Streamable HTTP MCP client. The Sites discovery route /api/mcp reaches the same engine.