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

Annotations already cover the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false), and the description adds genuinely new context: the response shape (updated set with image data stripped) and the auth/plan prerequisites. It does not warn that replacing the locale list drops stored translations, a data-loss detail left to the schema — mild given destructiveHint=false.

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 tight sentences: the first front-loads exactly what can be changed, the second carries return format and prerequisites. No filler and no redundancy with the title.

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 no output schema, the description usefully states what comes back, and it covers auth and plan gating for a mutating tool. The one gap is not surfacing the locale-replacement data loss, which an agent deciding whether to call this should know.

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 name, set_id, locales, and screen_order including the translation-loss caveat and the full-permutation requirement. The description restates the parameters at a high level without adding format or constraint detail, so the 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?

The description names a specific verb (update) and resource (screenshot set) and enumerates the three mutation surfaces — rename, replace extra-locale list, reorder screens. This clearly separates it from sonar_update_screenshot (singular) and sonar_create_screenshot_set.

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?

It gives real operating context: an Indie plan is required and either an authorized Sonar account or a write-scope API key is needed, plus the 'and/or' phrasing signals partial updates are allowed. It stops short of naming alternatives (e.g., when to use sonar_set_screenshot_translations instead) or stating when not to use this tool.

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