or_models

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

With no annotations, the description itself must convey behavior. It states 'List' (implying read-only) and identifies the filtered fields, but it does not disclose potential pagination, response structure, authentication requirements, or whether the listing is complete or capped. Adds some value beyond schema, but leaves gaps.

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 tight sentences: first announces the listing and its content, second gives usage and filter mechanism. No filler or repetition of schema elements. Every word serves a purpose.

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 no annotations and no output schema, the description covers the essential aspects: what the tool lists, the key fields (pricing, context length, modalities), when to use it, and how to filter. Lacks only minor operational details like default sorting or pagination, but is complete enough for a catalog listing tool.

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 descriptions cover 100% of the parameters, so baseline is 3. The description only mentions the parameter names ('search/supported_parameters/output_modalities') without adding operational details like OR-side semantics, but the schema already communicates this. No extra semantic value added.

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 starts with a specific verb+resource: 'List OpenRouter model catalog' and gives concrete included fields ('pricing per 1M tokens, context length, and modalities'). This clearly distinguishes it from siblings like or_model_get (single model) and or_models_user (user-specific view).

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?

Provides clear usage context: 'Use this to compare models or look up current prices.' It does not explicitly mention alternatives or when not to use this tool, but the stated purpose is enough to guide selection among nearby siblings.

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