dictionary_lookup

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds the useful detail of what is returned (definition, phonetics, examples), but says nothing about behavior for unknown words or whether multiple senses are returned.

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?

A single front-loaded sentence with no filler; the returned fields are listed efficiently. Nothing redundant, though it is brief to the point of under-specification on alternatives.

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 one-parameter lookup tool with full annotation coverage and no output schema, the description names the returned fields, which substitutes adequately for a return-value contract. Only the sibling-routing guidance is missing.

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?

Only one parameter ('word') at 0% schema description coverage, but the name is fully self-explanatory and the description's phrasing 'a word's definition' reinforces it. No added guidance on format, casing, or whether inflected forms resolve.

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 resource ('a word'), and enumerates the returned fields (definition, phonetics, examples). It does not distinguish itself from siblings like wiktionary_lookup or dictionary_lookup_language, which keeps it from a 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 versus wiktionary_lookup, dictionary_lookup_language, or urban_define, and no mention of prerequisites or language scope. The agent must infer usage purely from the name.

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