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

With no annotations, the description must carry the transparency burden. It discloses the return payload (IPA, definition, etymology, translations) and language coverage (47 languages), which is useful. However, it does not explicitly state that the tool is read-only, does not mention output format or absence of side effects, leaving some ambiguity.

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 description is a single sentence that front-loads the verb and resource. It could be slightly tighter (the phrase 'for verified agent output' is vague and adds little clarity), but overall it is efficient and not padded.

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 simple single-parameter tool, the description lists the main return fields and language scope, which is useful. However, without an output schema, it omits details about the response structure (e.g., JSON format) and any limitations (e.g., case sensitivity or partial matches). It is adequate but not thorough.

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?

The schema already describes the single parameter 'word' as 'English word' with 100% coverage. The description adds no additional meaning about the parameter's format, constraints, or examples, so it meets the baseline of 3 but does not exceed it.

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 states the tool's function: 'Look up any English word' and lists the specific data returned (IPA, definition, etymology, translations). It does not explicitly distinguish from sibling tools like define_term or translate_word, but the combined return fields imply a comprehensive lookup, so it earns a 4 rather than 5.

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?

There is no guidance on when to use this tool versus alternatives such as define_term, translate_word, or search_words. The description implies it is for full word lookups, but it never states that explicitly or provides exclusions, so it fails to guide tool selection.

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