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.
This record as markdown: /tools/io-github-dave-london-cargo/head.md
What head does on Cargo
AI agents call head to retrieve information from Cargo without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why head is rated Low
This tool performs a safe, read-only HTTP HEAD request that queries remote resources for metadata only. It has no side effects, cannot modify data, and cannot execute arbitrary code. The response is limited to headers with no body, making it purely informational. This is the lowest-risk classification.
From the tool's definition Tool description: 'Makes an HTTP HEAD request via curl and returns structured response headers (no body).' HEAD is a read-only HTTP method that retrieves headers without body content, used to 'check resource existence, content type, or cache headers' — no…
Attacks that exploit this kind of access
The rule that runs head safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Cargo, 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 is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Cargo, apply this rule, and every head call is checked against it from then on.
Questions about 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. It is categorised as a Read tool in the Cargo MCP Server, which means it retrieves data without modifying state.
Register the Cargo 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 Cargo. Nothing to install.
head is a Read tool with low risk. Read-only tools are generally safe to allow by default.
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.
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.
head is provided by the Cargo MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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