PluginBench
MCP Server
Active
Apache-2.0

AsDecided MCP Server

io.github.asdecided/core

Read-only access to deterministic engineering decisions stored in your repository, served to agents over MCP.

What is the AsDecided MCP server?

The AsDecided MCP server provides read-only access to engineering decisions, requirements, designs, and roadmaps stored as typed Markdown in a local repository. It uses a native Rust engine to validate and retrieve relevant decisions deterministically without embeddings, model calls, or hosted indexes. The same repository state always produces the same answer, ensuring consistency for AI agents.

AsDecided lets you store engineering knowledge—decisions, requirements, designs, roadmaps, and prompts—as structured Markdown in your git repository. The MCP server makes this knowledge accessible to AI agents like Claude and Cursor in a deterministic, read-only way. No external services, embeddings, or Python runtime required; everything runs locally with reproducible results.

How to install AsDecided

Copy-paste configuration for popular MCP clients.

transport: stdio
Config generated by PluginBench — verify against the source before use.
~/Library/Application Support/Claude/claude_desktop_config.json
{
  "mcpServers": {
    "core": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "ghcr.io/asdecided/core:mcp-v0.30.0"
      ]
    }
  }
}

Tools & capabilities

Tools this server exposes to the agent.

  • Decision retrieval — Retrieve relevant engineering decisions and requirements from the repository deterministically
  • Decision validation — Validate typed Markdown decisions for correctness and consistency
  • Repository querying — Query decisions, designs, roadmaps, and prompts stored in the local repository

Use cases

  • Have AI agents reference your team's engineering decisions and architectural guidelines while coding
  • Ensure agents follow your documented requirements and design patterns consistently
  • Query your decision log to find relevant past decisions for new problems
  • Validate that new decisions conform to your repository's structure and rules
  • Gate code changes against documented decisions and requirements

AsDecided MCP server FAQ

What is AsDecided?

AsDecided is a system for storing engineering decisions, requirements, and designs as typed Markdown in your git repository, with an MCP server that lets AI agents access this knowledge deterministically without embeddings or hosted services.

Is AsDecided free?

Yes, AsDecided is open-source under the Apache-2.0 license. The core engine and MCP server are free to use and self-hosted.

How do I install it in Cursor or Claude?

Install the native engine via Homebrew (`brew install asdecided/tap/asdecided-core`), Cargo (`cargo install decided decided-mcp`), or Scoop on Windows. Then configure your MCP settings to run `decided-mcp --root .` pointing to your repository.

Do I need authentication or external services?

No. AsDecided runs entirely locally with no hosted index, API calls, or authentication required. Your decisions stay in your git repository.

What format do decisions use?

Decisions are stored as typed Markdown files in a `decisions/` directory (or `rac/` in older repositories). The engine validates and retrieves them deterministically.

Can I use this with an existing repository?

Yes. You can migrate existing repositories with `decided migrate layout .`, which moves legacy `.rac/` and `rac/` directories to `.decided/` and `decisions/`.

README (reference)

Source of truth, from the repository.

AsDecided

Engineering decisions your agents can follow. Build, as decided.

AsDecided keeps requirements, decisions, designs, roadmaps, and prompts as typed Markdown in your repository. Its native Rust engine validates that knowledge, retrieves relevant decisions deterministically, and serves it read-only to agents over MCP.

No embeddings, model call, hosted index, or Python runtime is required. The same repository state produces the same answer.

Product site · Documentation · Canonical sources · Changelog

Install

Install the native engine and MCP server through Homebrew:

brew install asdecided/tap/asdecided-core

Rust users can install the decided CLI directly from crates.io:

cargo install decided
cargo install decided-mcp

Windows users can install both native executables through Scoop:

scoop bucket add asdecided https://github.com/asdecided/scoop-bucket
scoop install asdecided

Native decided and decided-mcp archives are also published on GitHub Releases.

Python API consumers should use the asdecided/sdk client SDK. It talks to the native engine; this repository does not ship a second Python engine or a PyPI package.

Start a repository

decided quickstart
decided validate decisions/
decided gate decisions/
decided gate decisions/ --code --base origin/main

New repositories use:

.decided/config.yaml
decisions/

Existing artifact IDs such as RAC-ABC123DEF456 are durable identities and do not change with the product name.

Migrate an existing repository

Migration is explicit and never runs during an ordinary command:

decided migrate layout . --dry-run
decided migrate layout .

The migration moves .rac/ to .decided/ and rac/ to decisions/. It refuses to overwrite either destination.

MCP

The official MCP Registry identity is io.github.asdecided/core. Its Registry package is the versioned local MCP image under ghcr.io/asdecided/core; Homebrew and Cargo remain direct native installation paths for the same Rust server.

The OCI server still needs an explicit repository grant:

docker run --rm -i -v "$PWD:/work:ro" \
  ghcr.io/asdecided/core:mcp-latest --root /work
{
  "mcpServers": {
    "asdecided": {
      "command": "decided-mcp",
      "args": ["--root", "."]
    }
  }
}

Architecture

Rust is the product engine and the only CLI/MCP runtime in this repository. The authoritative language-neutral compatibility fixtures live in asdecided-spec. Live-corpus validation is based on validity, determinism, freshness, and cache/no-cache equality.

Document ingestion remains an ancillary Python connector rather than part of the core engine. The retired Python engine is preserved for historical review at the immutable python-engine-final tag; it is not maintained or run in normal CI.

License

Apache-2.0. See LICENSE and NOTICE.

Governance and continuity

AsDecided core is solo-maintained and supported on a best-effort basis. The project does not depend on a hosted service: adopters keep their Markdown corpus in their own git repository, while the Apache-2.0 implementation and language-neutral specification remain public. See GOVERNANCE.md for the maintainer, release, support, and continuity posture.

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