prepare_visual_base

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

With no annotations, the description carries the full burden. It discloses the underlying model (Gemini 2.5 Flash Image) and the output format (data URL), which is useful. However, it does not mention side effects, permissions, error handling, or whether the operation is read-only or has any side effects. This is a generation tool, so some behavioral transparency is provided, but gaps remain.

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 a single, concise sentence that packs in the purpose, method, and output. Every word contributes to understanding, with no redundancy or filler. It is front-loaded with the most important information first, making it highly efficient.

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's low complexity (one parameter, no output schema), the description covers the essential aspects: what it does, the model used, and the return value (data URL). It does not discuss error conditions or prerequisites, but for a simple generation tool with a clear output, this level of completeness is sufficient. The lack of an output schema is compensated by the explicit return description.

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 0%, so the description must compensate. The only parameter, base_prompt, is mentioned in the description as the source for generating the background. This confirms its role but adds little beyond what the parameter name already implies. No examples or additional guidance are provided, so it meets the minimum but does not fully enrich the parameter semantics.

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 the tool's purpose: generating a cinematic background via Gemini 2.5 Flash Image for the dark_thumbnail archetype. It names a specific verb ('génère'), resource ('fond cinematic background'), and input ('base_prompt'). However, it does not explicitly distinguish this from sibling tools like render_visual, which could also generate visuals, so it lacks full sibling differentiation.

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 a clear usage context: it is intended for the dark_thumbnail archetype, which tells the agent when to use this tool. It does not explicitly mention alternatives or when not to use it, but the archetype restriction implies a specific scenario. This is clear context without exclusions, so it earns a 4 rather than a 5.

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