generate_variants

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

The description adds a genuinely useful behavioral disclosure: 'If the tool fails with a timeout, don't retry. Instead, try to get the screen with get_screen method every 30 seconds for up to 10 times before giving up.' This tells the agent the operation is effectively asynchronous and how to recover. It does not explain the destructiveHint=true implication beyond annotations, so it is not perfect.

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 short, front-loaded with the core purpose, and followed by a concise, actionable timeout instruction. Every sentence earns its place; there is no redundant filler or repetition of schema details.

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 rich schema, output schema, and annotations, the description covers the main non-obvious operational detail (timeout recovery via get_screen). It lacks explicit guidance on when to prefer this tool over siblings, but that gap is already captured in usage_guidelines. Overall, an agent has enough to call it correctly.

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 projectId, selectedScreenIds, prompt, variantOptions, modelId, and deviceType. The description only restates 'existing screens' and 'text prompt', adding little semantic value beyond the schema. Baseline 3 is 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?

The first sentence states a specific verb and resource: 'Generates variants of existing screens within a project using a text prompt.' This clearly identifies what the tool does and distinguishes it from creating screens from scratch. It does not explicitly name or differentiate from sibling tools like generate_screen_from_text or edit_screens, so it misses the top score.

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?

There is no guidance on when to use this tool versus generate_screen_from_text, edit_screens, or other siblings. The only procedural note is about timeout handling with get_screen, which is error-recovery guidance, not selection guidance. This is insufficient for choosing between alternatives.

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