# 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-go/head

## Facts

- Tool: `head`
- Server: Go (`Dave-London/Pare`) — https://policylayer.com/tools/io-github-dave-london-go.md
- 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 is a safe HTTP method used only to retrieve metadata about resources. It produces no side effects, modifies no data, executes no code, and cannot delete or move money. This is a straightforward Read operation with minimal blast radius if misused by an agent.

From the tool's own definition: "Tool makes an HTTP HEAD request and returns response headers with 'no body'. HEAD requests are read-only operations that retrieve metadata without side effects."

## Use case

AI agents call head to retrieve information from Go 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 Go:

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

## Other tools on Go (201)

- `branch` — Destructive — https://policylayer.com/tools/io-github-dave-london-go/branch.md
- `clean` — Destructive — https://policylayer.com/tools/io-github-dave-london-go/clean.md
- `package-clean` — Destructive — https://policylayer.com/tools/io-github-dave-london-go/package-clean.md
- `remove` — Destructive — https://policylayer.com/tools/io-github-dave-london-go/remove.md
- `reset` — Destructive — https://policylayer.com/tools/io-github-dave-london-go/reset.md
- `secret-delete` — Destructive — https://policylayer.com/tools/io-github-dave-london-go/secret-delete.md
- `tag` — Destructive — https://policylayer.com/tools/io-github-dave-london-go/tag.md
- `variable-delete` — Destructive — https://policylayer.com/tools/io-github-dave-london-go/variable-delete.md
- `workspace` — Destructive — https://policylayer.com/tools/io-github-dave-london-go/workspace.md
- `add` — Execute — https://policylayer.com/tools/io-github-dave-london-go/add.md
- `add-package` — Execute — https://policylayer.com/tools/io-github-dave-london-go/add-package.md
- `ansible-galaxy` — Execute — https://policylayer.com/tools/io-github-dave-london-go/ansible-galaxy.md
- `ansible-playbook` — Execute — https://policylayer.com/tools/io-github-dave-london-go/ansible-playbook.md
- `api` — Execute — https://policylayer.com/tools/io-github-dave-london-go/api.md
- `apply` — Execute — https://policylayer.com/tools/io-github-dave-london-go/apply.md
- `bazel` — Execute — https://policylayer.com/tools/io-github-dave-london-go/bazel.md
- `bisect` — Execute — https://policylayer.com/tools/io-github-dave-london-go/bisect.md
- `black` — Execute — https://policylayer.com/tools/io-github-dave-london-go/black.md
- `build` — Execute — https://policylayer.com/tools/io-github-dave-london-go/build.md
- `bundle-exec` — Execute — https://policylayer.com/tools/io-github-dave-london-go/bundle-exec.md
- `bundle-install` — Execute — https://policylayer.com/tools/io-github-dave-london-go/bundle-install.md
- `check` — Execute — https://policylayer.com/tools/io-github-dave-london-go/check.md
- `cherry-pick` — Execute — https://policylayer.com/tools/io-github-dave-london-go/cherry-pick.md
- `clippy` — Execute — https://policylayer.com/tools/io-github-dave-london-go/clippy.md
- `cmake` — Execute — https://policylayer.com/tools/io-github-dave-london-go/cmake.md
- `compose-build` — Execute — https://policylayer.com/tools/io-github-dave-london-go/compose-build.md
- `compose-down` — Execute — https://policylayer.com/tools/io-github-dave-london-go/compose-down.md
- `compose-up` — Execute — https://policylayer.com/tools/io-github-dave-london-go/compose-up.md
- `conda` — Execute — https://policylayer.com/tools/io-github-dave-london-go/conda.md
- `coverage` — Execute — https://policylayer.com/tools/io-github-dave-london-go/coverage.md
- …and 171 more: https://policylayer.com/tools/io-github-dave-london-go.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-go · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-dave-london-go