lighthouse_budget

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

The description adds value beyond annotations by stating that unknown budget keys are surfaced as non-fatal findings with hints (not silently ignored), and it describes the return value (per-metric verdict and overall pass/fail). This supplements the readOnlyHint, openWorldHint, idempotentHint, and destructiveHint annotations, with no 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?

The description is front-loaded with the primary action, then systematically covers budget keys, return behavior, and usage hint. Every sentence adds value without redundancy. It is compact yet comprehensive.

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 has 3 parameters (one nested object) and no output schema, the description is remarkably complete. It explains required and optional parameters, budget key validation, error handling for unknown keys, and the return format. Edge cases are addressed, making it self-sufficient.

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?

Although the input schema has 100% coverage with descriptions, the description adds significant meaning: it explains the scale for scores (0-100, not decimal), latency units (milliseconds), CLS unitless, and provides an example. It also elaborates on the budget dictionary behavior. This enriches the schema.

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's purpose: run PageSpeed Insights on a URL and compare results against a performance budget. It specifies the verb ('run', 'verdict') and resource ('PageSpeed Insights', 'performance budget'), and differentiates from siblings by focusing on budget enforcement rather than general analysis.

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 mentions the tool is useful as a CI/pre-deploy gate, providing clear when-to-use guidance. It also explains behavior for unknown keys. However, it does not directly contrast with sibling tools like 'psi_analyze' or mention when not to use, though the context is strong enough.

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