Url Security Headers

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

The description adds significant behavioral context beyond the annotations (readOnlyHint, idempotentHint, etc.). It clarifies that the tool returns static evidence, does not execute JS, rejects SSRF-sensitive destinations, and explains caching behavior. No contradiction with annotations.

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 two sentences long. The first sentence states the purpose and key constraints; the second addresses parameter usage. Every sentence is informative and front-loaded, with no wasted words.

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?

Given the tool's complexity (security headers assessment) and the presence of an output schema, the description covers all necessary aspects: purpose, constraints, caching behavior, and parameter usage. It is comprehensive for an agent to use correctly.

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?

With 100% schema description coverage, the baseline is 3. The description adds value by specifying that 'url' must be an absolute public HTTP(S) URL and that SSRF-sensitive destinations are rejected, and by providing clear guidance on the 'fresh' parameter (cache reuse vs new fetch). This goes beyond the schema descriptions.

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 states a specific verb ('Assess') and resource ('common response security headers') and clearly distinguishes from siblings by specifying it is static evidence, does not execute JavaScript or bypass access controls. This sets it apart from tools like url_headers or url_status.

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 description explicitly limits usage to 'public HTTP(S) resources' and clarifies that it does not execute JavaScript or bypass access controls. It also provides guidance on the 'fresh' parameter, explaining when to use true vs false. However, it does not directly compare against sibling tools for when to use alternatives.

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