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

Annotations already cover the safety profile (readOnly, idempotent, not open-world). The description adds real behavioral context beyond them: what the response includes (sources, maturity, canonical URL, ambiguity) and the key constraint that it never synthesizes a meaning.

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?

Two tight sentences with zero filler, and the core action plus its constraint are front-loaded ahead of the return-value summary.

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?

With no output schema, the description usefully enumerates the returned fields and the single, fully documented parameter. It is complete for a read tool with annotation coverage, though it omits ambiguity-resolution behavior and error/not-found handling.

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% and the schema already documents 'Exact term, slug, or alias'. The description restates the accepted forms without adding syntax, format, or validation detail, so the baseline 3 applies.

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?

States a specific verb ('look up') and a precise resource ('exact published slang term, slug, or alias'), and pinpoints the returned fields. It is distinguishable from siblings: 'exact' separates it from search_terms, and 'Never generates a meaning' separates it from decode_phrase.

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 word 'exact' implies you must already know the term, and 'Never generates a meaning' hints at when to reach for decode_phrase instead. However, no sibling is named and there is no explicit when-to-use/when-not statement, so routing is left to inference.

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