Check Security Headers

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the behavioral burden and does disclose the key behavior: it fetches the URL, examines response headers only, and notes risk for missing headers. It could add caveats about timeouts or error handling, but the core side effect (outbound fetch) and output behavior are stated.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

One tightly written sentence with no filler. It front-loads the action, enumerates the checklist items, and states the risk output.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter tool with no annotations or output schema, the description covers the input, the action, the checklist, and the general output nature. It does not specify exact return formatting, but the missing-header risk behavior is enough for an agent to select and call it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%: the only parameter, url, is already described with an example. The tool description simply says 'fetches a URL' and adds no additional parameter-level guidance beyond what the schema provides, so baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb and resource: it fetches a URL and checks response headers against a named security checklist. It is clearly distinct from siblings like check_http_status, check_ssl, and check_dns.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It clearly implies when to use it: when security-related response headers need to be verified for a URL. It does not explicitly name sibling alternatives or exclusion conditions, but the specific checklist makes the intended context obvious.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.