# 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.

Agent View of the PolicyLayer registry record for `head`. HTML page: https://policylayer.com/tools/io-github-dave-london-github/head

## Facts

- Tool: `head`
- Server: Github (`@paretools/github`) — https://policylayer.com/tools/io-github-dave-london-github.md
- Install: `npx -y @paretools/github`
- Homepage: https://github.com/Dave-London/Pare
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Allowed

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "head",
    "arguments": {}
  }
}
```

## 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 own 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…"

## Use case

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.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Github:

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

## Other tools on Github (201)

- `branch` — Destructive — https://policylayer.com/tools/io-github-dave-london-github/branch.md
- `clean` — Destructive — https://policylayer.com/tools/io-github-dave-london-github/clean.md
- `remove` — Destructive — https://policylayer.com/tools/io-github-dave-london-github/remove.md
- `reset` — Destructive — https://policylayer.com/tools/io-github-dave-london-github/reset.md
- `secret-delete` — Destructive — https://policylayer.com/tools/io-github-dave-london-github/secret-delete.md
- `stash` — Destructive — https://policylayer.com/tools/io-github-dave-london-github/stash.md
- `tag` — Destructive — https://policylayer.com/tools/io-github-dave-london-github/tag.md
- `variable-delete` — Destructive — https://policylayer.com/tools/io-github-dave-london-github/variable-delete.md
- `workspace` — Destructive — https://policylayer.com/tools/io-github-dave-london-github/workspace.md
- `worktree` — Destructive — https://policylayer.com/tools/io-github-dave-london-github/worktree.md
- `add` — Execute — https://policylayer.com/tools/io-github-dave-london-github/add.md
- `add-package` — Execute — https://policylayer.com/tools/io-github-dave-london-github/add-package.md
- `ansible-galaxy` — Execute — https://policylayer.com/tools/io-github-dave-london-github/ansible-galaxy.md
- `ansible-playbook` — Execute — https://policylayer.com/tools/io-github-dave-london-github/ansible-playbook.md
- `api` — Execute — https://policylayer.com/tools/io-github-dave-london-github/api.md
- `apply` — Execute — https://policylayer.com/tools/io-github-dave-london-github/apply.md
- `audit` — Execute — https://policylayer.com/tools/io-github-dave-london-github/audit.md
- `bazel` — Execute — https://policylayer.com/tools/io-github-dave-london-github/bazel.md
- `biome-check` — Execute — https://policylayer.com/tools/io-github-dave-london-github/biome-check.md
- `bisect` — Execute — https://policylayer.com/tools/io-github-dave-london-github/bisect.md
- `black` — Execute — https://policylayer.com/tools/io-github-dave-london-github/black.md
- `build` — Execute — https://policylayer.com/tools/io-github-dave-london-github/build.md
- `bundle-exec` — Execute — https://policylayer.com/tools/io-github-dave-london-github/bundle-exec.md
- `bundle-install` — Execute — https://policylayer.com/tools/io-github-dave-london-github/bundle-install.md
- `check` — Execute — https://policylayer.com/tools/io-github-dave-london-github/check.md
- `cherry-pick` — Execute — https://policylayer.com/tools/io-github-dave-london-github/cherry-pick.md
- `clippy` — Execute — https://policylayer.com/tools/io-github-dave-london-github/clippy.md
- `cmake` — Execute — https://policylayer.com/tools/io-github-dave-london-github/cmake.md
- `compose-build` — Execute — https://policylayer.com/tools/io-github-dave-london-github/compose-build.md
- `compose-down` — Execute — https://policylayer.com/tools/io-github-dave-london-github/compose-down.md
- …and 171 more: https://policylayer.com/tools/io-github-dave-london-github.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-dave-london-github · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-dave-london-github