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

Beyond the readOnlyHint annotation, it discloses rich behavioral detail: the exact dimensions returned (input, output, cached reads, tiers, context brackets), that a confidence level and agreeing sources accompany them, and that a non-selling channel returns the model with no prices. That last point is a genuinely useful edge-case disclosure the annotations do not cover.

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?

Front-loads the return contents before the channel nuance, and each sentence carries distinct information. The closing note on colliding labels is slightly niche but earns its place as return-shape guidance.

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 describing return content and does so: it enumerates the price dimensions, the confidence/source metadata, and the channel-driven outcome. An agent has enough to call it and interpret the response.

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 schema already documents the channel enum thoroughly, so the baseline is 3. The description adds meaning by framing the default as maker pricing vs. reseller rates and by spelling out the empty-result outcome, though it does not add format details beyond the schema.

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?

Starts with a specific verb+resource: 'Returns every current price for one model', and the word 'current' implicitly separates it from the sibling price_history while the per-model scope separates it from compare_models. An agent can tell what it fetches without opening the schema.

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?

Explains the default behavior (maker's own prices) and the condition that switches to reseller pricing via `channel`. It stops short of naming siblings explicitly (e.g. price_history for past prices, compare_models for cross-model comparison), so the agent must infer those boundaries.

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