generate_image

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

With no annotations, the description carries the full load and does disclose meaningful traits: the model gets validated, every result is written to disk inside a restricted local root, and a paid-usage flag is mandatory. It still omits cost behavior (max_cost_usd is only in the schema), overwrite semantics for filename/output_dir, and whether dry_run suppresses the paid call.

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?

Two compact sentences, front-loaded with purpose before constraints. No filler, though the paid-gate sentence could be merged to tighten further.

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 an 11-parameter generative tool with no annotations and no output schema, the description covers the mutation and the paid gate but leaves output shape (URLs? file paths? metadata?), cost guardrails, and the resolution/aspect-ratio relationship unexplained. Adequate as a minimum but incomplete.

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% across 11 parameters, so the description must compensate and it only explains allow_paid. The meaning and valid values of size vs resolution vs aspect_ratio, n's cap, dry_run, filename and output_dir interactions, and the cost ceiling are all left entirely undocumented.

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 and resource ('Gera imagens') plus the mechanism (dedicated OpenRouter /images endpoint) and a side effect (persists results under an authorized local root). It doesn't explicitly distinguish itself from sibling mutators like edit_image or generate_variations, but the purpose is unambiguous.

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?

It gives one real precondition ('A geração exige allow_paid=true'), which is genuinely useful routing information. However, it never says when to prefer this over edit_image, animate_image or generate_variations, nor when not to call it.

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