psi_run

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

With no annotations, the description carries full burden. It discloses that no OAuth is needed and an API key is used, which is helpful for understanding authentication behavior. However, it does not mention rate limits, error handling, or what happens if the key is missing, leaving gaps in transparency.

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 a single, information-dense sentence with no filler words. It front-loads the core purpose and adds the key usage detail about OAuth. 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?

Given no output schema, the description should ideally hint at return values (e.g., scores, reports). It does not, but the tool's purpose (Core Web Vitals + Lighthouse) implies typical results. For a simple analysis tool, this is adequate but not fully 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 100%, so the schema already explains parameters. The description adds value by specifying that 'locale' is e.g. 'ru, en', that 'category' refers to Lighthouse categories, and that 'strategy' defaults to 'mobile'. This enriches the schema definitions without redundancy.

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 the tool analyzes a URL using PageSpeed Insights, specifically mentioning Core Web Vitals and Lighthouse. This verb+resource combination is specific and distinguishes it from sibling tools like gsc_url_inspect or ga4_run_report.

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 states 'No OAuth needed; uses GOOGLE_PSI_API_KEY if set,' which provides clear guidance on when to use this tool (when OAuth is not required) compared to other tools that may need authentication. However, it does not state when not to use or mention alternatives.

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