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.
Tools & capabilities
Tools this server exposes to the agent.
Decision retrieval— Retrieve relevant engineering decisions and requirements from the repository deterministicallyDecision validation— Validate typed Markdown decisions for correctness and consistencyRepository 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
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.
Yes, AsDecided is open-source under the Apache-2.0 license. The core engine and MCP server are free to use and self-hosted.
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.
No. AsDecided runs entirely locally with no hosted index, API calls, or authentication required. Your decisions stay in your git repository.
Decisions are stored as typed Markdown files in a `decisions/` directory (or `rac/` in older repositories). The engine validates and retrieves them deterministically.
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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