RepoGrammar

Repository conventions for coding agents.

Documentation · Quickstart · Changelog · Contributing

RepoGrammar indexes repeated implementations in your repository and gives coding agents a source-backed read plan: examples of how this codebase implements a route, fixture, model, or data-access role, with the evidence behind each match. When the evidence is insufficient, it returns UNKNOWN with a recovery action.

It runs locally and exposes a pattern-first CLI and one read-only MCP tool. There are no LLM calls, API keys, embeddings, or cloud services in the analysis path. Python 3.10+ is required for the bundled Python analyzer.

Recorded from a real CLI run on a fixture repository; playback is slowed for readability.

Quick start

Requires Python 3.10+, Bash, curl, tar, and gzip. macOS and glibc Linux are supported. Rust, Cargo, Node.js, Docker, and API keys are not required.

1. Install — copy and run

This single block downloads the pinned installer, verifies its checksum, and installs the CLI. It does not alter coding-agent settings or index a repository.

(
set -eu
install_tmp="$(mktemp -d)"
trap 'rm -rf "$install_tmp"' EXIT
cd "$install_tmp"
curl -fsSLO https://github.com/SioYooo/RepoGrammar/releases/download/v0.5.0/install.sh
curl -fsSLO https://github.com/SioYooo/RepoGrammar/releases/download/v0.5.0/install.sh.sha256
if command -v sha256sum >/dev/null 2>&1; then
  sha256sum -c install.sh.sha256
else
  shasum -a 256 -c install.sh.sha256
fi
bash install.sh --version v0.5.0 --install-cli-only --yes
) &&
export PATH="$HOME/.local/bin:$PATH"
repogrammar version

Add the export PATH line to ~/.zshrc or ~/.bashrc once to keep the command available in new terminals. Expected version: 0.5.0.

2. Index your project

From your project's directory:

repogrammar init

That is all: init builds the current project's index and starts background updates. There is no global repository scanner. Run init once in each project. The explicit form repogrammar init --project "$PWD" --yes does the same thing; use --no-autosync for CI or a one-shot index.

3. Connect your coding agent (optional)

repogrammar install --target auto --scope global --yes --no-telemetry

Restart the coding-agent session after connecting. Choose a specific client with --target codex, --target claude-code, or --target opencode.

Related MCP server: Repo Context Forge

When should I index again?

index remains available for compatibility. Use init to start, sync for ordinary changes, and resync to rebuild. Do not repeatedly run init after normal edits.

Usage

Find examples for an exact repository location:

repogrammar find "path/to/routes.py:7" --project "$PWD" --mode compact
repogrammar families --project "$PWD"
repogrammar sync --project "$PWD"

Start with an exact path or symbol when available. Framework-qualified queries such as FastAPI route are also supported. See the CLI reference for the complete commands and the MCP contract for coding-agent integration.

Background updates

init starts a daemon for that repository. On macOS and Linux, native file notifications coalesce edits before a sync. Idle native operation reconciles metadata periodically instead of rescanning the tree every second. Git-ignored untracked directories are pruned before fingerprint traversal, while tracked files and ignore exceptions remain visible.

If native watching fails, autosync logs the fallback and polls with bounded idle backoff. Failed syncs retry with bounded backoff even without another edit. File notifications are hints; explicit sync and query-time hashes remain the freshness authority. These changes reduce background work; no battery-life percentage is claimed.

repogrammar autosync status --project "$PWD"
repogrammar autosync stop --project "$PWD"
repogrammar autosync start --project "$PWD"

For CI or one-shot analysis, initialize with --no-autosync. See the autosync contract for intervals and recovery.

How it works

repository → local index → pattern families → examples + bounded read plan
                                └──────────→ UNKNOWN + recovery action

• Repository conventions: find compatible implementations and their exceptions.

• Verifiable context: every result carries provenance and freshness checks.

• Incremental updates: native filesystem events wake autosync; changes use the existing incremental indexer. Periodic reconciliation and polling fallback handle unavailable watchers.

• Agent integration: connect Codex, Claude Code, or opencode through MCP.

Text search finds strings; symbol graphs connect declarations and references. RepoGrammar adds evidence about repeated implementation patterns. Use them together. Static alignment is not proof of runtime equivalence.

Scope and limitations

The official language focus is Python: FastAPI, pytest, Pydantic, and SQLAlchemy. Other languages have bounded structural or dependency-inventory capabilities; these are not full language support. The strict Top-20 qualification program remains 0/20 complete. Read the language audit for the evidence and unresolved gates.

RepoGrammar is pre-1.0. It is not a sound whole-program analyzer, and neither a syntax match nor a dependency declaration proves behavior. Dynamic dispatch, unsupported frameworks, stale indexes, and incomplete semantics can result in abstention. Read known limitations before relying on a result.

Public binary targets are macOS arm64/x86_64 and glibc Linux arm64/x86_64. Windows and musl Linux are not supported installation targets.

Development

cargo build --locked
cargo test --workspace --all-features

Read CONTRIBUTING.md and the testing policy for the full checks. Architecture and specifications live in docs/. Report bugs through GitHub Issues; report security issues according to SECURITY.md.

License

MIT.