Model details

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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds genuinely new behavioral context beyond them: the call is free and it returns live capacity and rate limits, which tells the agent this is a cheap, safe call that can be made liberally. It stops short of describing response shape or whether capacity figures are real-time snapshots.

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?

One front-loaded sentence opening with 'Everything about one model:' followed by a compact enumeration of returned fields. It is dense with parentheticals but every clause adds information and there is no filler; a light restructure of the nested parentheses would make it a 5.

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 output schema, the description carries the burden of explaining return values, and it does so by listing the field groups an agent will receive. Combined with read-only annotations and a fully documented single parameter, an agent has enough to call it correctly; only the response format (object shape, units) is left unstated.

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 coverage is 100% and the single parameter already documents that an exact model id is required. The description reinforces the one-model-per-call framing but adds no format, casing, or aliasing details beyond the schema, so baseline 3 applies.

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 states a specific resource (one model) and enumerates the payload precisely: catalogue row with capabilities and constraints (video durations, music lengths, TTS voices), Carpe price, Venice rate limits and live capacity. That is far more informative than a tautology, though it never names the sibling it replaces (carpe_list_models for discovery, carpe_pricing for cross-model price comparison).

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 infer this is the single-model lookup while carpe_list_models is the multi-model list, but the description does not say when to prefer this over carpe_pricing or carpe_rate_limits, nor any prerequisites. The 'e.g. from carpe_list_models' hint lives in the schema, not the description, so the discovery-to-detail flow is left implicit.

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