rna-mcp

Repo-Native Alignment

Coding agents are blind to the shape of your codebase. RNA fixes that: it runs as an MCP server alongside your agent and gives it one call to answer "what depends on this?", "what relates to payment processing?", or "how is the reliability outcome progressing?" — questions LSP alone cannot answer.

Single binary. No Docker. No external database. No API key.

Quick Start | Why RNA | MCP Tools | Docs

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Why RNA

LSP gives agents single-symbol, single-hop, single-language queries. There's no multi-hop primitive, no semantic search, no connection to business artifacts.

Finding blast radius with LSP alone:

textDocument/references("ConnectionPool")     → [PoolManager, HttpServer, Worker]
callHierarchy/incomingCalls(PoolManager)      → [AppConfig, TestHarness]
callHierarchy/incomingCalls(HttpServer)       → [main, Router]
callHierarchy/incomingCalls(Worker)           → [Scheduler]
// agent must: filter test files, deduplicate, reason about the shape

With RNA:

search(query="ConnectionPool", mode="impact", max_hops=3)
→ PoolManager → AppConfig
→ HttpServer → main, Router
→ Worker → Scheduler
// production code ranked first, test files demoted, cross-language

Job	LSP alone	RNA
What breaks if I change this?	N round-trips of incomingCalls, agent assembles graph	search(mode="impact") — one call, transitive
Find code related to a concept	No semantic search — agent must guess names and grep	search("payment processing") — ranked by meaning across code, docs, and artifacts
How is our reliability outcome progressing?	Not possible — LSP has no business context	outcome_progress("reliability") — commits → files → symbols
Orient a new agent to the repo	Multiple searches, no subsystem picture	repo_map() — subsystems, hotspots, entry points in one call

RNA runs LSP servers internally. It fuses their data with tree-sitter, embedded function bodies, git history, and business artifacts into a cross-language graph — so the agent gets the LSP depth without doing the LSP orchestration.

What Changes After Installing

Four jobs agents can do after RNA is running that they could not do reliably before:

Find code by meaning, not just by name search("payment processing") returns ranked results across symbols, docs, commits, and artifacts in one call. Path scoping works too: search("auth/handlers/validate") returns only symbols named validate in files matching auth/handlers.

Trace call paths and blast radius search(node="AuthHandler", mode="impact") returns transitive dependents grouped by subsystem. search(node="X", mode="path", query="Y") returns the directed call chain between two nodes.

Connect code to business outcomes outcome_progress("agent-alignment") follows tagged commits to changed files to affected symbols. Outcomes, signals, and guardrails in .oh/ are full graph nodes — searchable, linkable, tracked.

Orient instantly in an unfamiliar repo repo_map() returns detected subsystems (from actual call relationships), top symbols by PageRank, hotspot files, and active outcomes. One call instead of an exploratory loop.

Quick Start

1. Install

Claude Code users (recommended):

# 1. Add the marketplace
claude plugin marketplace add open-horizon-labs/repo-native-alignment

# 2. Install the plugin
claude plugin install rna-mcp

# 3. Restart Claude Code, then run the setup skill:
/rna-mcp:setup

Setup detects your platform (optimized binary for M2+ chips with bf16/i8mm), downloads the binary to ~/.cargo/bin/, configures .mcp.json, and updates AGENTS.md with tool guidance.

Download a prebuilt binary (manual):

# macOS Apple Silicon (M2+ optimized — bf16/i8mm)
curl -L https://github.com/open-horizon-labs/repo-native-alignment/releases/latest/download/repo-native-alignment-darwin-arm64-fast.tar.gz | tar xz -C ~/.cargo/bin

# macOS Apple Silicon (M1 baseline)
curl -L https://github.com/open-horizon-labs/repo-native-alignment/releases/latest/download/repo-native-alignment-darwin-arm64.tar.gz | tar xz -C ~/.cargo/bin

# Linux x86_64
curl -L https://github.com/open-horizon-labs/repo-native-alignment/releases/latest/download/repo-native-alignment-linux-x86_64.tar.gz | tar xz -C ~/.cargo/bin

Build from source (requires Rust toolchain):

git clone https://github.com/open-horizon-labs/repo-native-alignment.git
cd repo-native-alignment
cargo install --locked --path .

2. Connect to your MCP client