list_image_models

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

With no annotations, the description carries the full behavioral burden and mostly does: it discloses that the catalog is live, cached for 10 minutes, and that moderation status may be unknown ('?'). It does not mention auth requirements or rate limits, but for a read-only listing that is a minor gap.

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?

Front-loaded with the action, then usage, then a column inventory, then args. The column enumeration is lengthy but earns its place because there is no output schema; slightly over-detailed for a listing tool.

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?

No output schema exists, so the description supplies the return shape by naming every column and its semantics (inputs, aspect ratios, resolutions, quality, max n, seed, moderation, price units). Combined with the cache/liveness note and full param docs, an agent has everything needed to call and interpret it.

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 — and it does, defining all four args: case-insensitive query scope, accepts_images tied to edit_image needs, author as the id prefix before '/', and both sort values with their defaults and ordering.

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 (List) and resource (image models on OpenRouter), plus the output shape (markdown table) and liveness of the catalog. It is clearly separable from sibling get_image_model, which is explicitly scoped to 'one model's per-provider details.'

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?

Gives an explicit when-to-use rule: 'Use this before generate_image or edit_image to choose a model and see which options it takes.' It also routes the agent elsewhere when only one model is needed ('Call get_image_model for one model's per-provider details'), and warns against stale remembered model ids.

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