Lema Mcp
- 1 repo stars
- Updated July 27, 2026
- lemahq/lema-mcp
Lema Mcp is a local Model Context Protocol server that returns cited why-was-this-decided answers from RFCs and ADRs for developers who need to avoid re-proposing approaches already ruled out in React, Kubernetes, Rust,
About
lema-mcp is a local Model Context Protocol server installed with npx lema-mcp that surfaces recorded engineering rationale instead of hallucinated backstory. The public demo serves React, Kubernetes, and Rust decision corpora through check_approach, returning ruled_out, settled, or no_recorded_ruling verdicts with citations to RFC and PR sources. Running npx lema-mcp init on your repo captures decisions to .lema/decisions.json, installs guard hooks, and enables record_decision, check_decided, and search_decisions over your ADR graph. No account is required for the public corpus; your own repo stays local-first with optional hosted retrieval. Reach for lema when an agent is about to add an approach that maintainers may already have rejected or when you need a cited answer to why React, K8s, or your team chose a pattern.
- check_approach returns ruled_out, settled, or no_recorded_ruling with RFC/PR citations
- record_decision captures chosen option plus rejected alternatives append-only to .lema/decisions.json
- Public demo corpus covers React, Kubernetes, and Rust without an account
- npx lema-mcp init installs PreToolUse guard hooks that surface CLOSED decisions before edits land
Lema Mcp by the numbers
- Data as of Jul 28, 2026 (Skillselion catalog sync)
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| repo stars | ★ 1 |
|---|---|
| Package | lema-mcp |
| Transport | STDIO |
| Auth | None |
| Last updated | July 27, 2026 |
| Repository | lemahq/lema-mcp ↗ |
Why was this technical decision made in the repo?
Checks proposed approaches against recorded RFC/ADR verdicts and captures settled decisions with rejected alternatives via MCP tools and guard hooks.
Who is it for?
Developers using Claude Code, Cursor, or VS Code who need cited architectural rationale from RFCs, KEPs, ADRs, or team-captured decisions before proposing changes.
Skip if: Developers seeking API syntax docs or teams unwilling to maintain `.lema/decisions.jsonl` decision capture should use a docs MCP instead of lema-mcp.
What you get
Cited decision verdicts, `.lema/decisions.jsonl` capture records, ADR search results, and optional PreToolUse guard nudges.
- cited decision verdicts
- decisions.jsonl capture file
- PreToolUse guard nudges
By the numbers
- Public demo covers 3 projects: React, Kubernetes, and Rust
- Enforcement benchmark ran 168 trials across 2 public repos
- Local capture writes append-only `.lema/decisions.jsonl`
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Use lema-mcp for cited why and ruled-out verdicts; use a docs MCP when you only need API reference syntax.
FAQ
Which public projects does lema-mcp cover without an account?
lema-mcp public mode serves read-only recorded decisions for three projects—React (`react-rfcs`), Kubernetes (`k8s-enhancements`), and Rust (`rust-rfcs`)—via `npx lema-mcp try <name>` with no API key.
What does lema-mcp store for a team's own repository?
Running `npx lema-mcp init` captures settled decisions—including rejected alternatives and rationale—to a commit-friendly `.lema/decisions.jsonl` file and installs guard hooks that surface CLOSED options before edits land.