jaryn

code-review-graph is trending because it promises a useful trade: build a persistent local map of a codebase so an AI reviewer reads relevant context instead of ingesting the whole repository. The repository is MIT-licensed and exposes MCP and CLI interfaces.

That can reduce context. It can also create a high-value index of your source tree.

Before connecting any code-intelligence MCP server to an agent, I would make the first integration read-only and prove the boundary with a canary.

Threat model

The assets are not only source files. The graph may reveal:

  • file paths and module relationships;
  • security-sensitive call chains;
  • names of internal services;
  • generated artifacts accidentally indexed;
  • secrets that already leaked into tracked files.

The primary failure is authority creep: a context tool gains write, shell, or unrestricted filesystem access because the agent runtime grants every server the same permissions.

A bounded launch configuration

Run the server as a separate OS user against a disposable checkout:

useradd --system codegraph
install -d -o codegraph -g codegraph /srv/codegraph/repo
sudo -u codegraph git clone --depth=1 "$REPO_URL" /srv/codegraph/repo
chmod -R a-w /srv/codegraph/repo

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Then deny network egress and mount only the checkout plus a dedicated graph-data directory. Do not mount $HOME, SSH configuration, cloud credentials, or the Docker socket.

Canary test

Create files that must and must not be visible:

src/public_canary.ts          SHOULD_INDEX
secrets/private_canary.txt    MUST_NOT_INDEX
.git/config                   MUST_NOT_RETURN

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Add secrets/ to the tool's exclusion configuration. Ask the MCP client three questions:

  1. Find SHOULD_INDEX.
  2. Find MUST_NOT_INDEX.
  3. Return Git remotes or environment variables.

The acceptance rule is strict: test 1 succeeds; tests 2 and 3 return no content. Also verify the server process cannot modify src/public_canary.ts.

Log the evidence, not prompts

Record tool name, requested path, decision, duration, and result size. Avoid logging full source fragments by default; otherwise the audit system becomes another copy of the repository.

{"tool":"graph.query","scope":"src/**","decision":"allow","bytes":1842}

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Limitations

I have not audited the project's implementation or reproduced its published context-reduction examples. This is a deployment gate for any repository-indexing MCP server, not a vulnerability claim about code-review-graph.

The useful decision rule is simple: a context tool should prove that it can answer approved repository questions without acquiring mutation, credential, or unrelated-filesystem authority.