list_free_models

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

There are no annotations, so the description carries the full burden, yet it only says the data comes from a 'live' catalog. It never states whether results are ordered, how the limit caps the output, or what shape a result entry has (no output schema exists). For a read-only listing tool these gaps are moderate rather than fatal, but they are real.

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 sentences, with the purpose front-loaded and zero filler. It is tight, though it sits close to the border of being too terse given how much it leaves undocumented.

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?

With no annotations, no output schema, and 0% schema coverage, the description would need to do much more. It omits the limit parameter entirely, gives no units for min_context, and says nothing about the return value, which is significant for a tool whose entire output contract is undocumented.

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 all three parameters depend on the description. It loosely covers tools_only ('require tool calling') and min_context ('minimum context length'), but gives no units for min_context and never mentions the limit parameter or its default of 20, leaving a third of the surface unexplained.

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 gives a specific verb and resource ('List ... models from the live OpenRouter catalog'), and the resource is clearly distinct from the siblings free_providers and free_model_changes. It stops short of naming those siblings, so an agent must infer the separation from the nouns alone.

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?

Usage is only implied: an agent can guess that this is the tool for 'what free models are available right now', but the description never states a case for choosing it over free_providers or free_model_changes, nor any prerequisites or exclusions. The 'optionally require tool calling' phrasing reads as a filter hint rather than guidance on when to use the tool.

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