MCP Configuration

MCP (Model Context Protocol) lets Peon AI connect to external tool servers — for example a documentation lookup server, a web search server, or any custom MCP-compatible service. The connected tools become available to the developer agent during implementation.

Setup

Open Window → Preferences → AI Peon → Peon MCP Configuration.

Each server entry has a Type — HTTP (Streamable), HTTP (legacy SSE), or STDIO (local process) — plus common fields shared by all types.

Common fields

Field	Description
Name	Display name shown in the UI and used in log output.
Protocol Version	Dropdown with Auto, 2025-11-25, 2026-07-28, plus free text (e.g. 2024-11-05). Auto (empty) is the default and lets the client detect the version the server supports. 2025-11-25/2024-11-05 = Legacy, 2026-07-28 = modern. Any other value triggers version detection, which can fail with -32022 on dual-era servers.

HTTP fields

Two HTTP transports are supported:

• HTTP (Streamable) — the current MCP transport. Single endpoint (typically /mcp) that accepts JSON-RPC over POST and may upgrade to SSE for streaming responses. Use this for new servers.
• HTTP (legacy SSE) — the older transport from the 2024-11-05 spec. The client opens an SSE channel at /sse and posts messages back to a URL the server returns. Use this for servers that only expose /sse (e.g. docs-mcp-server).

If you get Unexpected status code: 405, you are most likely pointing the wrong transport at the server — switch between Streamable and legacy SSE.

Field	Description
URL	Endpoint of the MCP server. For Streamable, e.g. https://mcp.context7.com/mcp. For legacy SSE, e.g. http://127.0.0.1:6280/sse.
API Key	Optional Bearer token. Leave empty if the server requires no authentication.

STDIO (local process) fields

STDIO servers run as a local subprocess. Peon AI starts the process and communicates over its stdin/stdout. This is useful for MCP servers that need access to personal credentials or local system resources.

Field	Description
Command	Executable to launch, e.g. uvx or npx.
Arguments	Space-separated arguments passed to the command, e.g. duckduckgo-mcp-server.
Environment Variables	Optional environment variables in KEY=VALUE format, one per line. Use this to pass tokens or configuration without exposing them in a URL.

Example — DuckDuckGo web search via uvx:

Type:      STDIO (local process)
Name:      duckduckgo-mcp
Command:   uvx
Arguments: duckduckgo-mcp-server
Env:       DDG_SAFE_SEARCH=STRICT

Prerequisite: uvx requires uv to be installed and available on the system PATH.

Enabling MCP

Enable the MCP toggle in the chat toolbar to activate the configured servers. Peon AI connects to all servers on toggle-on and disconnects on toggle-off. If any server fails to connect, all servers are disconnected and an error is shown.

Changes apply live: saving the MCP preference page reconnects the servers with the new configuration immediately — no restart needed. If the configuration is unchanged, nothing is reconnected.

Notes

• MCP tools are exposed to every agent on the shared registry — developer, planner and custom agents — and to Peon-PO (Jon) via his own registry, and to the search sub-agent (which does include them). Exposed does not mean unrestricted: the per-agent tool allowlist (see Custom agents / agent config) filters MCP tools exactly like built-in tools.
• The search sub-agent (used during planning and implementation) also has access to MCP tools, so read-only MCP servers (e.g. documentation lookup, web search) are useful there too.
• If any configured server fails to connect, all servers are disconnected and an error is shown — this prevents the agent from working with an incomplete tool set.
• Tool names are taken directly from the server. If two servers expose a tool with the same name, the last one registered wins.

Codegraph (built-in)

Codegraph is a built-in feature — do not add a codegraph entry here. It activates automatically when the active project is indexed (.codegraph/); see Codegraph. The server name codegraph is reserved: if an old manual entry still exists, it is skipped (with a log line) and the built-in wins.

Suggested MCP Servers

Server	Type	Hosting	Best for
Context7	HTTP	Cloud (free)	Up-to-date docs for React, Spring, Vite and many other frameworks. No setup required.
DuckDuckGo MCP	STDIO (uvx duckduckgo-mcp-server)	Local	Privacy-friendly web search without an API key.
docs-mcp-server	HTTP (Streamable or legacy SSE)	Self-hosted	Any documentation site you can crawl. Fully private — nothing leaves your machine.
openapi-mcp	HTTP	Self-hosted	REST APIs with an OpenAPI 3.x spec. Exposes each endpoint as a callable tool.