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

With no annotations provided, the description carries the full behavioral burden. It discloses a key edge-case behavior (empty result for unknown word or missing thesaurus) and positions the tool as the agent twin of the GET /thesaurus page. It doesn't describe the return format or any rate limits, but for a simple lookup with one parameter, the disclosed behavior is meaningful.

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 sentences, roughly 30 words, with no redundancy. The core definition is front-loaded, followed by the edge-case behavior and a helpful reference to the corresponding page. Every sentence earns its place.

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?

For a single-parameter lookup tool with no output schema and no annotations, the description covers the purpose, the parameter's role, and the empty-result edge case. The main omissions are the return structure and explicit guidance on when to prefer this tool over other word-related siblings, so it falls just short of fully complete.

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 0%, and the description does not explicitly document the 'word' parameter. However, the phrase 'for a word' conveys that the parameter is the lookup term, adding some implicit semantics. It lacks details like case sensitivity, trimming, or formatting, so it only partially compensates for the schema's total lack of 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?

The description clearly specifies the resource (a word's thesaurus entry) and the content (WordNet synonyms and broader IS-A terms), distinguishing it from adjacent word tools like word_occurrences or word_study. It opens with a noun phrase rather than an explicit verb ('Returns' or 'Looks up'), and 'the words that stand with it' is slightly vague, but the WordNet synonym/hypernym phrasing is concrete enough for an agent to understand the operation.

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 implies when to use the tool: when you need synonyms or broader terms for a word. It also states an edge-case condition ('Empty when the word is unknown or no thesaurus is loaded'). However, it names no alternatives or exclusions, so it doesn't explicitly help an agent choose between this and similar word tools in the sibling list.

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