List Vision Models (Vision Helper)

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

The annotation already covers read-only, idempotent, non-destructive behavior, so little additional safety disclosure is needed. The description adds useful behavioral context about the live nature of OpenRouter availability and what the result contains: model IDs, context length, and input price.

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 front-loaded with the main purpose and organized into clear functions: what the tool lists, when to use it, how to narrow/paginate, and what is returned. It is efficient but slightly repeats the picking-a-model idea across the first two clauses.

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?

Since there is no output schema, the description usefully specifies the return contents: model IDs, context length, and input price. Combined with the annotations, it gives an agent everything needed to select and invoke the tool 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?

Input schema coverage is 100%, so the schema already documents limit, offset, and search well. The description adds a small amount of practical guidance about search and pagination, but does not materially extend the schema's meaning beyond paging and search usage.

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 the exact action: list vision-capable models currently available on OpenRouter. Purpose is further clarified with concrete use cases, such as finding a valid model ID when a configured model fails, and the resource is clearly distinct from the sibling analyze_image and check_config tools.

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?

Clearly says when to use the tool: when a configured model fails, when asked what models are available, or when choosing a model for image analysis. It gives practical navigation guidance via search and pagination, though it does not explicitly name alternatives or state when NOT to use it.

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