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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the bar is lower, yet the description adds valuable context: source file (LiteLLM price file, MIT), daily recording, signed responses, payment requirement ($0.01 USDC via x402 on Base or Solana). It doesn't describe output format or pagination details, but the payment and provenance info is substantial behavioral transparency.

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?

The description is a single dense sentence that front-loads the resource and scope, followed by a compact source and payment note. It's efficient, though the embedded payment details make it slightly less clean than a pure functional description.

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?

For a read-only tool with no output schema, the description covers what changes are included, time range, filtering, source, and payment. It could specify output format or response structure, but given annotations and the nature of the tool, this is largely 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 description coverage is 0%, so the description must compensate for three undocumented parameters. It mentions 'last 1 to 90 days' (implying the 'days' parameter) and 'optionally by provider or model name', which maps to the other two. However, no syntax or format details are given (e.g., whether 'days' is a string range, how model names are specified), leaving significant ambiguity.

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+resource: recent changes to AI model prices and availability across providers, newest first. Distinguishes from sibling ai_prices by emphasizing changes (deltas) rather than current prices, which an agent can grasp without opening either 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?

Gives clear context: last 1 to 90 days, optionally filtered by provider or model name. It doesn't explicitly name alternatives like ai_prices, but the scope is implied clearly enough that an agent knows this is for change history.

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