AI agents use create_webhook to create or update resources in GitHub Repos Manager MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your GitHub Repos Manager MCP Server environment.
Creating a webhook establishes a persistent outbound channel that sends repository event data to an arbitrary external URL. This is a Write operation (creates a new resource), but carries high severity because a malicious or misconfigured webhook could exfiltrate sensitive repository events (pushes, PRs, secrets in payloads) to attacker-controlled endpoints.
From the tool's definition "Create event webhooks" — creates a new webhook resource on a GitHub repository
Documented attack patterns abuse exactly the kind of access create_webhook gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and GitHub Repos Manager MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for create_webhook:
{
"version": "1",
"default": "deny",
"tools": {
"create_webhook": {
"limits": [
{
"counter": "create_webhook_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_webhook 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.
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Create event webhooks. It is categorised as a Write tool in the GitHub Repos Manager MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the GitHub Repos Manager MCP Server MCP server in PolicyLayer and add a rule for create_webhook: 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 Repos Manager MCP Server. Nothing to install.
create_webhook 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 create_webhook 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 create_webhook. 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.
create_webhook is provided by the GitHub Repos Manager MCP Server MCP server (kurdin/github-repos-manager-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from GitHub Repos Manager MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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84 GitHub Repos Manager MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.