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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds genuine value beyond that: 'Saves nothing' explicitly confirms non-persistence, and it enumerates the supported locales, which the annotations do not convey. Return format is left to the output schema.

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 short sentences, front-loaded with the core purpose, then the non-persistence note and supported locales. No filler; every clause 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?

With an output schema present, return values need not be explained, and annotations cover the safety profile. The description covers purpose, non-persistence, and locale constraints, leaving only sibling differentiation as a minor gap.

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%, so the baseline is 3, and the description exceeds it by enumerating the actual supported locale values (en-us, ko-kr, etc.) rather than the vague 'such as ko-kr or en-us' in the schema. It adds a real constraint on the locale parameter.

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: it returns IPA candidates for a word. The phrase 'for the user to choose between' and 'differ on purpose and are not ranked' clarifies the intent well. It does not explicitly distinguish itself from the sibling preview_pronunciation, which limits it below 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?

'For the user to choose between' implies this is a suggestion step before selection, and 'Saves nothing' signals it is non-persistent. However, it never names alternatives such as preview_pronunciation or save_dictionary_entry, so when-to-use versus siblings is only implied.

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