Pick local phrasing

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

Annotations already declare this as a non-destructive, idempotent write, so the safety profile is covered. The description adds the useful constraint that the phrase must be one of the locale's measured candidates from get_optimizer, but it does not explain what happens to the prior phrasing, whether the draft must be in a particular state, or what the response contains.

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, though the nested phrasing ('different measured candidate phrase for a core phrase (from that locale's candidates...)') is slightly convoluted. It earns its place and avoids bloat.

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 mutation tool in the optimizer workflow with no output schema, the description covers the core action and candidate source, and annotations cover safety. It remains thin on state prerequisites and post-call effects, leaving the agent to infer how this fits with optimizer_choose, optimizer_save_option, and optimizer_localize.

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 all four parameters (locale, keyword, phrase, projectId) are already documented, including the phrase being a candidate and the keyword being the main-locale core phrase. The description's reference to get_optimizer candidates adds slight linkage but no syntax or format detail beyond the schema, making the baseline 3 appropriate.

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 ('use a different...candidate phrase') and resource, scoped to one locale draft, and points to get_optimizer as the source of candidates. It does not explicitly distinguish itself from close siblings like optimizer_choose or optimizer_save_option, 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?

The phrase 'In one locale draft' implies when this applies and the parenthetical indicates the phrase must come from that locale's candidates in get_optimizer. There are no explicit exclusions, prerequisites, or named alternatives, so guidance is implied rather than stated.

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