Generate a structured pre-merge review of the current git diff. Returns each changed symbol with its blast radius, test coverage, and an overall risk rating (LOW/MEDIUM/HIGH/CRITICAL). Use this before committing or opening a PR.
AI agents call review_diff to retrieve information from GraphHub without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is a pure analysis and reporting tool. It examines the current git diff and synthesizes information into a review document, but performs no side effects on the codebase, repository state, or any external system. The tool informs decision-making (whether to commit or open a PR) but does not itself execute those actions. It falls squarely into the 'Read' category as a query and analysis function.
From the tool's definition The tool 'review_diff' generates a structured analysis and returns information about changes (blast radius, test coverage, risk rating) without modifying, executing, or deleting anything.
Documented attack patterns abuse exactly the kind of access review_diff gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and GraphHub, and nothing reaches the server without passing your rules. This is the rule we recommend for review_diff:
{
"version": "1",
"default": "deny",
"tools": {
"review_diff": {}
}
}review_diff is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Generate a structured pre-merge review of the current git diff. Returns each changed symbol with its blast radius, test coverage, and an overall risk rating (LOW/MEDIUM/HIGH/CRITICAL). Use this before committing or opening a PR. It is categorised as a Read tool in the GraphHub MCP Server, which means it retrieves data without modifying state.
Register the GraphHub MCP server in PolicyLayer and add a rule for review_diff: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches GraphHub. Nothing to install.
review_diff is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the review_diff rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for review_diff. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
review_diff is provided by the GraphHub MCP server (slnquangtran/graph-hub). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from GraphHub, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
32 GraphHub tools catalogued and risk-classified — across an index of 43,000+ MCP servers.