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

Annotations already declare readOnlyHint=true and openWorldHint=true. Description adds valuable context: 'Lean mode — no bundle stored' clarifies no data persistence, and explains truncation behavior via max_tokens and the truncated field in the return. This goes beyond annotations without contradicting them.

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?

Description is brief (4 sentences + return structure + examples) and front-loaded with the core action. Every sentence provides unique value: purpose, lean mode, usage guidance, alternative, and return fields. No filler or redundancy.

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 (100% schema coverage), annotations, and a described output schema, the description fully covers: what it does, when to use, alternatives, input parameters, return structure, and behavioral quirks (no storage, truncation). Completeness is high relative to tool complexity.

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?

Input schema has 100% coverage with descriptions for all parameters. The description does not add new semantic details beyond the schema; it merely restates examples. Baseline 3 is appropriate as schema already handles parameter documentation.

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?

Description clearly states the tool fetches a public HTTPS URL and returns its content translated into a target language. It distinguishes itself from sibling url.extract by noting that url.extract extracts raw untranslated text. The verb 'translate' and resource 'URL content' are specific and unambiguous.

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 tells when to use ('when you need to understand web content in a different language') and when not to use ('For extracting raw untranslated text, use url.extract instead'). This provides clear decision guidance with a named alternative. Example prompts reinforce usage scenarios.

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