head

Makes an HTTP HEAD request via curl and returns structured response headers (no body). Use to check resource existence, content type, or cache headers.

SERVERGithub SOURCE@paretools/github

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-dave-london-github/head.md

WHAT IT DOES

What head does on Github

AI agents call head to retrieve information from Github without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why head is rated Low

HEAD requests are inherently read-only operations that query HTTP response headers without side effects. The stated purpose—checking resource existence and retrieving metadata—confirms no data is created, modified, deleted, or executed. While it can make network requests, the impact is purely informational retrieval, placing it firmly in the Read category with low severity.

From the tool's definition Tool description states it 'Makes an HTTP HEAD request via curl and returns structured response headers (no body)' with use cases limited to 'check resource existence, content type, or cache headers.' HEAD requests are idempotent, read-only HTTP operations…

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs head 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 head, this is the rule to start with:

head Allowed

head is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "head": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

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

FAQ

Questions about head

What does the head tool do? +

Makes an HTTP HEAD request via curl and returns structured response headers (no body). Use to check resource existence, content type, or cache headers. It is categorised as a Read tool in the Github MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on head? +

Register the Github MCP server in PolicyLayer and add a rule for head: 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 head? +

head is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit head? +

Yes. Add a rate_limit block to the head 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 head completely? +

Set action: deny in the PolicyLayer policy for head. 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 head? +

head is provided by the Github MCP server (@paretools/github). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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