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

Annotations already mark the tool as read-only; the description adds per-call payment via USDC/USDT on Base, x402, and a 3-free-calls-per-wallet quota. This is meaningful behavioral context beyond the annotations, though it doesn't describe payment failure or edge cases.

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 sentences; the first front-loads the core operation and outputs, the second covers payment terms. No filler or redundancy.

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?

Given an output schema exists and annotations declare read-only behavior, the description's coverage of purpose, inputs, and payment is sufficient. Minor omissions like behavior when neither location nor timezone is supplied are edge-case details.

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 explains wallet, api_key, location, timezone, and x_payment. The description's payment sentence reinforces the wallet/x_payment purpose but adds little beyond what the schema already provides.

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 concrete outputs (local time, UTC offset, DST status, abbreviation) and two input modes: IANA timezone names and place-name resolution. This distinguishes it from sibling geocoding/weather tools by the resource and output it acts on, even though no sibling is named.

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 conditions for use: any IANA timezone name, or a place name to resolve to a timezone. Payment/free-tier note also informs usage, but it does not explicitly contrast with sibling tools like geocode or geo_ip.

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