roam-code

The local codebase intelligence layer that lets AI coding agents earn the right to change code — with evidence for what was checked.

Credential-free · 100% local by default (opt-in metrics-push is the only outbound surface) · tamper-evident ChangeEvidence packets · Apache 2.0 · runs entirely on your machine

275 commands · 244 MCP tools (16 in the default core preset) · 28 languages

Jump to — Why Roam · Install · The Compiler · Core commands · MCP server · AI-tool integration · Roam Guard (PR gate) · Performance · Compare · Pricing · FAQ

Why Roam is different

METR and FrontierCode both point at the same gap: passing tests is not the same as mergeable code. Roam is an agent-first CLI surface that gives the agent local graph facts before it edits, gates risky changes, and emits scoped evidence after the run. In the agent/review tools surveyed as of 2026-06-12, the differentiator is this combination:

• Credential-free. No account, no API key, no cloud login. pip install and run.
• 100% local by default. Source code never leaves the machine; air-gapped repos work like cloud repos. The single outbound surface (roam metrics-push) is opt-in, summary-only, and prints its exact payload under --dry-run.
• Tamper-evident ChangeEvidence packets. A Roam-guided change can compile into one portable packet — HMAC-chained run ledger + signed Code Graph Attestation + signed PR bundle — answering eight questions: who acted, what authority existed, what context was read, what changed, what could break, what policy applied, what verified it, who accepted risk. PR Replay maps those eight questions today: structural change/risk/policy axes are in scope, context and verification are partial, and missing identity/authority/approval evidence is disclosed instead of invented. Cursor logs the run; Roam records and verifies the evidence its producers captured.
• MCP runtime security at the wrapper boundary. Every MCP response is scrubbed for secrets on egress, gated against the active mode (read_only / safe_edit / migration / autonomous_pr) with a closed-enum policy_decision, and each decision receipt is HMAC-linked into the signed run ledger. Inside-server controls; the gateway layer (Interlock / Lasso / Portkey) composes on top — see dev/MCP-SECURITY-POSTURE.md.

Underneath sits a SQLite-backed graph of symbols, calls, imports, layers, git history, runtime traces, smells, clones, security flows, and algorithmic patterns across 28 languages — the same local facts queried before, during, and after a change.

Dependency-aware, not string-based. Roam knows Flask has 47 dependents and 31 affected tests; grep knows it appears 847 times. One command replaces 5-10 tool calls — <0.5s per query, plain-ASCII output, --json and --sarif envelopes for agents and CI.

Illustrative — a typical agent workflow on a 200-file Python project (Flask). Reproducible smoke transcript in docs/fresh-install-smoke.md; full indexing-rate harness in benchmarks/. Exact numbers vary with repo size, agent prompt, and model.

Install + first four commands

About two minutes from pip install to a verdict on whether your next edit is safe.

pip install "roam-code[mcp]"          # 1. install with MCP server for Claude Code / Cursor / Continue
cd /path/to/your/repo
roam init                             # 2. index the repo into .roam/index.db (one-time, ~30s on most repos)
roam health                           # 3. composite 0-100 score: complexity, cycles, dark-matter coupling, dead code
roam preflight <symbol>               # 4. blast radius + tests + complexity + architecture rules before you edit

Python 3.10+. pipx install roam-code and uv tool install roam-code work too. Drop [mcp] for CLI-only. See docs/fresh-install-smoke.md for a verbatim transcript of these four commands against a clean venv.

Step 4 is the payoff — roam preflight on a hot symbol returns a verdict before you touch it:

$ roam preflight open_db
VERDICT: Significant risk — CRITICAL, 1847 symbols in blast radius

Pre-flight check for `open_db (src/roam/db/connection.py:799)`:

  Blast radius:     1847 symbols in 382 files                [CRITICAL]
  Affected tests:   617 direct, 962 transitive               [OK]
  Complexity:       cc=30, nest=4                            [CRITICAL]
  Coupling:         2 files often change together            [MEDIUM]
  Conventions:      no violations                            [OK]

  Overall risk: CRITICAL
  Risk driver:  complexity (cc=30, CRITICAL)

An agent sees the blast radius before it edits — not after the tests fail.

pipx install roam-code                                   # isolated environment (recommended)
uv tool install roam-code                                # uv-managed tool
pip install git+https://github.com/Cranot/roam-code.git  # from source

# Docker (alpine-based)
docker build -t roam-code .
docker run --rm -v "$PWD:/workspace" roam-code index
docker run --rm -v "$PWD:/workspace" roam-code health

Works on Linux, macOS, and Windows. Windows: if roam is not found after installing with uv, run uv tool update-shell and restart your terminal.

The Compiler — your agent's first token already knows the answer

You ask your agent "who calls handleSave?" and watch it grep, open three files, grep again, read a fourth — six turns and $1.30 later you get the answer the repo's call graph held all along.

Roam ships a task compiler that ends that loop. Before your prompt reaches the model, roam recognizes what kind of question it is, runs the right code-graph lookups locally (~90 ms, zero model calls), and puts the answers into the prompt: the caller list with line numbers, the git history already filtered, the source around the bug line you cited. The agent's first words can be the answer.

For Claude Code it's one command, zero configuration:

pip install "roam-code[mcp]"
cd your-repo && roam init
roam hooks claude --write     # compile-before + verify-after, wired into Claude Code

Then use claude exactly as you always do. Undo anytime with roam hooks claude --uninstall --write. A broken install can never block your agent — every hook is fail-open.

What that buys you, measured head-to-head on Claude (same prompts, same repo, with and without the compiler — June 2026, 41 cells):

The same shape reproduces on Opus (−86% turns). And the compiler knows where it doesn't help: prompts that ask the agent to write code get no envelope at all — injection there was measured as pure overhead, so it spends your tokens only where it wins.

The last two rows were the published LOSSES (trivial prompts once paid the envelope for nothing at +$0.20; generation once cost +17%). After the generatio