update_pull_request_branch

Update the branch of a pull request with the latest changes from the base branch.

SERVERGitHub SOURCEoci:ghcr.io/github/github-mcp-server:1.3.0

Medium RISK CLASS

Category Write

Parameters 40 required

Recommended Rate-limitedsee the rule below

Registry record Grade D, identity verified Pull the record →

This record as markdown: /tools/github/update-pull-request-branch.md

WHAT IT DOES

What update_pull_request_branch does on GitHub

AI agents use update_pull_request_branch to create or update resources in GitHub, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your GitHub environment.

Parameter	Type	Required	Description
`repo`	string	—	Repository name
`owner`	string	—	Repository owner
`pullNumber`	number	—	Pull request number
`expectedHeadSha`	string	—	The expected SHA of the pull request's HEAD ref

Parameters from the server's own tool schema.

RISK

Why update_pull_request_branch is rated Medium

This tool modifies the state of a pull request branch reversibly—it updates the branch to incorporate upstream changes, which is a standard git operation. It does not delete data (not Destructive), execute arbitrary code (not Execute), create new records (Write rather than just Create), or involve financial transactions (not Financial).

From the tool's definition Tool performs an update operation on a pull request branch, modifying the branch state by incorporating latest changes from the base branch. The verb 'update' combined with 'branch' indicates data modification rather than retrieval or destruction.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs update_pull_request_branch safely

PolicyLayer is an MCP gateway: it sits between your AI agents and GitHub, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For update_pull_request_branch, this is the rule to start with:

update_pull_request_branch Rate-limited

update_pull_request_branch 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "update_pull_request_branch": {
      "limits": [
        {
          "counter": "update_pull_request_branch_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect GitHub, apply this rule, and every update_pull_request_branch call is checked against it from then on.

FAQ

Questions about update_pull_request_branch

What does the update_pull_request_branch tool do? +

Update the branch of a pull request with the latest changes from the base branch. It is categorised as a Write tool in the GitHub MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

What parameters does update_pull_request_branch accept? +

update_pull_request_branch accepts 4 parameters: repo, owner, pullNumber, expectedHeadSha. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on update_pull_request_branch? +

Register the GitHub MCP server in PolicyLayer and add a rule for update_pull_request_branch: 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 GitHub. Nothing to install.

What risk level is update_pull_request_branch? +

update_pull_request_branch is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit update_pull_request_branch? +

Yes. Add a rate_limit block to the update_pull_request_branch 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.

How do I block update_pull_request_branch completely? +

Set action: deny in the PolicyLayer policy for update_pull_request_branch. 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.

What MCP server provides update_pull_request_branch? +

update_pull_request_branch is provided by the GitHub MCP server (oci:ghcr.io/github/github-mcp-server:1.3.0). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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