Quote a chat request across markets

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

Annotations already establish a safe, idempotent, closed-world read, so the bar is lower; the description still adds real value by disclosing that the result compares two surfaces and enumerates each market's price, availability, and TEE status. It could have said more about how the input-size estimate is derived or what happens when a model is unknown.

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 compact sentences with zero filler, and the core promise ('Price... BEFORE running it') is front-loaded before the optional inputs are described. The /v1 and /router jargon is dense but each term is immediately glossed.

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 the response, and it does outline the comparison plus per-market price, availability, and TEE flag. Edge cases such as unknown models or empty estimates are not covered, which keeps it just short of complete.

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%, so the baseline is 3, but the description goes beyond per-field docs by explaining the relationship between the inputs: messages or prompt drive the input-token estimate, while input_tokens overrides it outright. That mutual-exclusivity guidance is genuinely additive rather than a restatement of 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?

States a specific verb and resource ('Price a text request') and scopes it precisely: it reports what /v1 alone would bill and what /router would pick across markets. That is clearly distinguishable from siblings like carpe_chat (which executes) and carpe_pricing/carpe_markets (which expose static price/market data).

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?

The phrase 'BEFORE running it' tells the agent this is the pre-flight step ahead of carpe_chat, and 'Costs nothing' removes any hesitation about calling it. It stops short of explicitly naming the alternatives to use when the user only wants static pricing or market lists.

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