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

The description adds value beyond annotations: it mentions 'Requires a write-scope API key' (auth requirement) and states 'The set is immediately visible/editable for humans in the Screenshot Studio (studio_url in the response).' These details reveal behavioral traits like persistence and immediate availability. No contradiction with annotations (readOnlyHint=false, 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?

The description is three sentences long, front-loaded with the core purpose in the first sentence. The second sentence provides a key prerequisite, and the third sentence covers both immediate effect and authentication. Every sentence is necessary and no words are wasted.

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?

Given the tool has 6 parameters (3 required) and no output schema, the description covers what the tool does, prerequisites, immediate effect, and auth requirements. It mentions the studio_url in the response but does not detail the full response structure or error/validation conditions. For a creation tool, it is largely complete, but could a bit more about potential failure modes or output shape.

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?

While schema coverage is 100% (baseline 3), the description adds meaningful extra guidance: for the 'screens' parameter it explains the need to read the layout guide first and clarifies that 'Either this or template_id, not both; with neither you get one blank screen.' For 'device_size' it provides an example ('iphone-6.7') and references the sonar_screenshot_devices tool. This surpasses the schema's raw descriptions.

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 begins with 'Create an app-store screenshot set for a product,' which clearly states the verb (create) and resource (screenshot set). It distinguishes this from sibling tools like sonar_add_screenshot, sonar_list_screenshot_sets, sonar_update_screenshot_set, and sonar_delete_screenshot_set by focusing on initial creation and referencing the prerequisite guide.

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 description instructs users to 'Read sonar_screenshot_layout_guide first, then author the screens array,' providing a clear prerequisite for correct usage. It also notes the immediate visibility in Screenshot Studio, implying post-creation state. However, it does not explicitly state when not to use this tool (e.g., if updating an existing set, use sonar_update_screenshot_set instead).

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