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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful context: the 147,000-word corpus size and automatic inflection resolution. It does not say what happens on a miss (unknown word, error vs empty result), so it is solid but not rich.

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 first two sentences overlap ('English definitions of a word. Word definitions.'), with the second carrying no information. The third is a dense but load-bearing feature list, so the text is front-loaded but contains one wasted sentence.

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 must carry return-value burden, and it largely does: definitions partitioned by part of speech, usage examples, synonyms/antonyms, broader terms, IPA/ARPAbet, syllable count, rhymes and prefix autocomplete. Missing only error/empty-result behavior for words outside the corpus.

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 word, pos and limit are already documented in the schema; baseline 3 applies. The phrase 'definitions by part of speech' loosely hints at the pos filter but adds no format, default, or interaction detail beyond 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?

States a specific verb+resource ('English definitions of a word') and enumerates the exact payload the agent gets back, so the function is unmistakable. However, the second sentence 'Word definitions' is pure tautology, and the description never acknowledges the sibling tools rhymes and synonyms even though it claims to return those same data types, leaving routing ambiguity.

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?

No when-to-use guidance and no exclusions are given. The only contextual note is that inflected forms (running, cities) resolve automatically, which is useful but is a capability statement, not usage direction. An agent has no help deciding between this, rhymes, synonyms, or spell_check.

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