AI agents use update_merge_request to create or update resources in Git MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Git MCP Server environment.
The tool modifies merge request state/metadata (status, title, description, reviewers, etc.) but does not irreversibly delete data or execute arbitrary code. This places it in the Write category. Severity is high because uncontrolled MR updates could alter code review workflows, CI/CD configurations, or team collaboration processes in a Git repository, affecting multiple stakeholders.
From the tool's definition Tool name 'update_merge_request' indicates modification of merge request data. Sibling tools on the server include 'create_merge_request' and 'close_merge_request', establishing that this server manages Git operations including MR lifecycle.
Documented attack patterns abuse exactly the kind of access update_merge_request gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Git MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for update_merge_request:
{
"version": "1",
"default": "deny",
"tools": {
"update_merge_request": {
"limits": [
{
"counter": "update_merge_request_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_merge_request stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
update_merge_request. It is categorised as a Write tool in the Git MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Git MCP Server MCP server in PolicyLayer and add a rule for update_merge_request: 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 Git MCP Server. Nothing to install.
update_merge_request is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the update_merge_request 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 update_merge_request. 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.
update_merge_request is provided by the Git MCP Server MCP server (yumeminami/git_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Git MCP Server, 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.
33 Git MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.