speed_audit

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

Discloses it is READ-ONLY, lists all activities (HTML heuristics always, optional PageSpeed Insights), and specifies return elements (Core Web Vitals, Lighthouse opportunities, recommendations with category 'speed'). No annotations exist, so the description fully informs behavioral traits without contradictions.

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?

Three well-structured sentences with no wasted words: first sentence states core purpose and nature, second details functionality and conditional behavior, third provides alternative. Every sentence is necessary and front-loaded with key information.

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 a single parameter, no output schema, and no annotations, the description covers all needed context: tool action, scope, optional dependencies, return types, and relationship to sibling tool. It is complete for an agent to correctly invoke and interpret results.

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% with a single 'url' parameter described as 'The exact page URL to measure'. The description adds no further meaning about the URL parameter 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 clearly states it performs a 'READ-ONLY speed-only audit of ONE page', specifying the resource (page URL) and action (audit). It distinguishes itself from the sibling tool 'audit_site' which handles whole-site, multi-pillar audits. The verb 'audit' combined with 'speed-only' and 'ONE page' provides precise purpose.

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?

Explicitly states when to use (single page speed audit) and when to use alternative ('Use audit_site for a whole-site, multi-pillar audit'). Also notes conditional behavior based on PAGESPEED_API_KEY setting, guiding the agent on prerequisites and expected output variations.

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