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

Discloses key behavioral traits beyond annotations: may use stored data or AI generation, language coverage and quality vary, requires authentication/entitlement, and counts toward quotas. This adds real context not present in the annotations (which only indicate non-read-only, open-world, non-idempotent, non-destructive). No contradiction.

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 sentences, each earning its place: purpose, behavior/requirements, and sibling routing. Purpose is front-loaded, 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?

Covers purpose, behavior, prerequisites, side effects, and the key alternative. Lacks an explicit statement about return value, but for a translation request this is reasonably inferable; the absence of an output schema makes a brief mention of output format desirable, though not critical.

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 fully documents both parameters. The description adds no extra parameter-specific details beyond restating 'supplied text and a target language'; baseline 3 applies because the schema carries the load.

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?

Clearly states the verb 'Request' and the resource 'translation' for supplied text and target language. Explicitly differentiates from the sibling lookup_words by noting that tool only inspects existing translations, so the agent can distinguish them without opening schemas.

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?

Provides a direct alternative: 'Use lookup_words to inspect only existing translations.' This tells the agent when to choose the sibling instead. Also gives preconditions (Word Orb key, plan entitlement) and a caveat (coverage/quality vary), covering both when-to-use and when-not-to-use.

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