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

With no annotations, the description carries the full burden and does well: it discloses the plan prerequisite ('Requires an active trial or Pro'), the return shape, and a review caveat for sensitive/legal/technical output. It omits rate limits and reversibility, but for a non-destructive text adaptation tool those gaps are minor.

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?

Front-loads the differentiating purpose in the first sentence, then usage, params, return, and prerequisites in sequence. Dense but each sentence earns its place; slightly long with the trailing reviewer caveat, though that adds real value.

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?

No output schema exists, and the description compensates by enumerating the returned JSON fields (localized text, targetLanguage, locale, provider, model). Combined with the plan requirement and review caveat, an agent has everything needed to call and interpret this tool.

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 100%, so the schema already documents all five parameters with examples. The description reinforces required vs optional (targetLanguage required; locale, audience, tone optional) but adds no syntax or format detail beyond what the schema provides, so baseline 3 applies.

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 (adapt text for localization) and immediately distinguishes itself from literal translation, naming the sibling translate_text as the alternative. An agent can route between localize_text and translate_text without opening either schema.

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?

Explicit when-to-use list (localized product UI, marketing copy, documentation, customer communications) and an explicit when-not with the named alternative ('use translate_text for a closer translation'). Nothing is left to inference.

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