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. It clarifies that the tool performs multiple checks and returns the header to add for each, which is useful. But it does not disclose whether it makes live network requests, whether it is read-only, or what happens when a URL is unreachable or returns non-HTTP responses.

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?

The description is one tight, front-loaded sentence that lists the checks and the output nature ('each with the header to add') without any filler. Every part earns its place.

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 output schema, the description is largely complete: it names the input, the full set of checks, and the nature of the output. It could be more explicit about the result format or failure behavior, but those are minor gaps given the tool's simplicity.

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?

The input schema already documents the single url parameter at 100% coverage, including examples like localhost dev servers. The description adds little beyond 'on a URL', so the baseline of 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 ('Check') and a precise resource/scope: security headers on a URL, enumerating HTTPS, redirect, HSTS, nosniff, clickjacking, CSP, Referrer-Policy, and X-Powered-By. It also notes the output includes the header to add, which distinguishes it clearly from sibling checks like check_routes or check_link_preview.

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?

The intended use is implied: call this tool when you need to evaluate a URL's security headers and get recommended remediation headers. However, it does not explicitly state when to prefer this over check_basics or other sibling tools, nor does it mention any exclusions or prerequisites.

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