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

Annotations already declare the mutation/safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=true). The description adds genuinely useful context beyond that: the plan gating, the auth requirement, and that the set becomes immediately human-visible in the Screenshot Studio with studio_url returned. It does not spell out non-idempotency, but annotations cover that.

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?

Three sentences, front-loaded with the core action, then reference routing, then side effects and prerequisites. No filler; every sentence carries distinct information.

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 steps in to note the returned studio_url, and it covers plan/auth prerequisites and the input-source alternatives. Nothing an agent needs to call this mutation correctly 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?

Schema description coverage is 100%, so the schema already documents all six parameters, including the screens/template_id exclusivity and the device_size reference to sonar_screenshot_devices. The description only restates the screens-vs-template choice, adding no format or syntax beyond the schema. 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 (Create) and resource (app-store screenshot set), scoped to a product, and names the two input modes (own screens layouts or built-in template). This distinguishes it from siblings like sonar_add_screenshot and sonar_update_screenshot_set without opening any 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?

Routes the agent to sonar_screenshot_layout_guide for the JSON format and template ids, and states prerequisites (Indie plan, authorized account or write-scope API key). It does not give an explicit when-not-to-use case versus sonar_add_screenshot or update_screenshot_set, so it falls short of a 5.

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