Compare Models

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so the agent knows this is a safe, repeatable, closed-world read. The description adds that the output includes a pick and per-model break-even token share, which is useful context, but discloses nothing about auth, rate limits, or computation constraints.

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?

It is a single sentence with no wasted padding, and the core action is front-loaded. However, the phrasing 'for a kind of work' and the trailing 'with the break-even share of answer tokens for each against the pick' is syntactically tangled and slows comprehension for an agent scanning tool definitions.

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?

An output schema exists, so return-format explanation is unnecessary, and all six parameters are schema-documented. The remaining gap is routing: for a catalog with nine closely related model/cost tools, the description never positions this against its siblings, leaving the agent to guess when comparison is warranted.

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 100%, so the schema already documents all six parameters, including the pay enum semantics and the answer_tokens override. The description only glancingly maps to parameters (plan use, break-even share of answer tokens); it adds no naming, format, or default guidance beyond the schema, so the baseline of 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 concrete verb-ish action (two to six models side by side) plus the resource (models for a kind of work) and enumerates the outputs: rating, prices, cost per task or plan use, a pick recommendation, and break-even answer-token share. That is specific enough to separate it from pure pricing tools like estimate_cost, though the sibling differentiation is implicit rather than stated.

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?

There is no when-to-use or when-not-to-use guidance. With siblings like estimate_cost, find_models, and suggest_for_project in the same catalog, the description never says when comparing multiple models is the right call versus costing or discovering a single one.

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