Generate image

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

With no annotations, the description carries the full burden. It discloses key behaviors: provider fallback (Gemini then Grok), file output (writes a PNG under the runs directory), and return value (path plus provider). It doesn't cover failure modes or auth/rate limits, but for this tool the disclosed behavior is substantial and directly actionable.

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 compact—three sentences—and front-loads the primary action and fallback. Every sentence provides essential information (what, how to phrase prompt, output behavior). No redundant wording or fluff.

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?

For a tool with 6 parameters, 1 required, and no output schema, the description covers the essential context: purpose, fallback, output location, and return content. It doesn't describe the full parameter matrix, but the schema handles that. The description sufficiently orients the agent without needing to repeat schema details.

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 high (83%), so the schema already explains most parameters. The description adds minimal parameter context—chiefly emphasizing that the prompt should be subject-only and that style is applied automatically. This aligns with existing schema descriptions, so the description adds limited extra meaning beyond the schema.

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 clearly states a specific action: 'Generate a photograph with Gemini, falling back to Grok.' It identifies the resource (a photograph/PNG) and outcome (writes a PNG, returns path and provider). This distinguishes it from siblings like upload_image, which handle existing images rather than generating new ones.

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 provides explicit guidance on how to use the tool: 'Pass `prompt` as the SUBJECT ONLY' and explains that style is applied automatically. It doesn't explicitly contrast with alternatives (e.g., when to use upload_image instead), but the generation context is clear, making the usage circumstances easy to infer.

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