Mcp Project Context

mcp-project-context

Host-side injection of project identity into existing MCP tool parameters.

This reference implementation shows how an MCP host can give tools current-project focus by filling parameters such as owner and repo before the call is dispatched. The server receives a normal, complete tools/call and requires no modification.

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Problem

Many MCP tools (including those in the official github-mcp-server) declare owner and repo as required parameters. When a user asks an agent to act on "this project," the host already knows the repository identity. Without that identity being supplied, the agent is forced into an exploration phase:

1. List repositories
2. Guess which one is current
3. Possibly ask the user

This costs context and latency. The friction is tracked in github/github-mcp-server#1683.

Solution

The host:

1. Obtains the current project identity from a local source
2. Inspects the target tool's own inputSchema (via tools/list)
3. Fills only parameters that are both declared by the tool and currently missing from the call
4. Dispatches an ordinary tools/call

project identity          HOST                          SERVER
(project.faf, .git,   →   inspect inputSchema        →  ordinary tools/call
env, workspace…)         fill missing fields only      (unchanged)

The server is unaware of the injection. No roots, no new protocol primitives, and no server-side cooperation are required. The same host logic works against any MCP server whose tools already declare matching parameter names, including the current github-mcp-server.

Why not Roots

SEP-2577 deprecated Roots in part because of vague semantics and overlap with tool parameters and server configuration. An earlier experiment, mcp-current-repo, used Roots to carry project identity; that surface is no longer viable. Parameter injection uses the surface the SEP itself named as the natural alternative.

Render project.faf

npx faf-cli show

Renders the current project.faf as an HTML card (IANA media type application/vnd.faf+yaml).

Demo

npm install && npm run demo

The demo runs the identical tool call twice against an unmodified stub server that mirrors the required parameters of real github-mcp-server tools:

Before (plain callTool):

⛔ owner/repo are required — none supplied.
   A real agent now has to enumerate repos, guess, or ask the user.

After (same call routed through callToolWithFaf):

· auto-filled from project.faf: owner, repo
✅ Scoped to octocat/Hello-World
   No exploration phase. No server-side change required.

   issues in octocat/Hello-World:
     #1 Set up CI [open]
     #2 Write the README [open]

The server binary is byte-for-byte identical in both runs. Only the host changed.

Core logic

src/param-fill.ts (48 lines). It:

• Reads the tool's own inputSchema
• Fills only parameters that are both present in the schema and missing from the call arguments
• Never overrides an explicit argument supplied by the caller

Identity source is deliberately source-agnostic. This demo reads its repository field from project.faf; a production host can derive the same value from .git, environment variables, or workspace configuration.

What this is

A reference implementation of a host-side pattern for discussion.

What this is not

• Not a library or package intended for installation
• Not an MCP server
• Not a proposal for new protocol surface
• Not a full project-context system

The value is the mechanism. Hosts that already know the current repository can implement the same logic directly.

Related

• github/github-mcp-server#1683
• SEP-2577 (Roots deprecation)
• Predecessor (now obsolete): mcp-current-repo
• Successor: faf-trinity — extends this same param-fill pattern to all three IANA FAF formats (context, memory, agent identity), not just context

Citation

> Wolfe, J. (2025). Format-Driven AI Context Architecture: The .faf Standard for Persistent Project Understanding. Zenodo. https://doi.org/10.5281/zenodo.18251362

> Wolfe, J. (2026). Why Agents Need a Passport: .fafa — Portable Identity for the Agentic Era. Zenodo. https://doi.org/10.5281/zenodo.21951641

MIT

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Wolfe-Jam
• Source: Wolfe-Jam/mcp-project-context
• License: MIT

Install and usage instructions live in the source repository linked above.