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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds a genuinely useful behavioral note ('The total can be a lower bound') and explains what include_headers does, but says nothing about result volume, pagination, or rate limits.

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?

Two compact sentences, front-loaded with the primary purpose before the optional-parameter note. Slightly dense shorthand ('the matching scripts') but nothing is wasted.

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?

An output schema exists, so return values need not be spelled out. However, given 0% schema coverage and an undocumented limit parameter, plus no guidance on large result sets despite the 'lower bound' caveat, the description is only adequate rather than complete.

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 description coverage is 0%, so the description must carry the burden. It explains server_type via examples and clarifies include_headers ('adds the HTTP headers'), but leaves limit completely unexplained in both schema and description.

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?

Specific verb ('Find') plus resource ('JavaScript') and the exact selection dimension ('type of web server that served it'), with concrete examples ('nginx', 'microsoft'). This clearly distinguishes it from the many sibling by_cdn/by_bundler/by_library fingerprint searches.

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 examples imply how to populate server_type, but there is no when-to-use guidance and no mention of the numerous near-identical sibling tools (search_js_fingerprint_by_cdn, by_bundler, etc.) or when this is preferred over them. The agent must infer the boundary from the tool name alone.

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