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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is clear. The description adds crucial behavioral context beyond annotations: it is a paid tool at $0.002 USDC per call via x402 on Base, Solana, Polygon, or Arbitrum, with automatic payment for x402 MCP clients and a free sample call.

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 purpose and usage, then parameters, then pricing and free sample. Payment details are necessary for a paid tool, though the note about x402 MCP clients is slightly verbose. Overall well-structured and appropriately sized.

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 simple tool with no output schema, the description covers return fields (current local time, UTC offset, DST flag, weekday), usage scenarios, and payment mechanics. Everything an agent needs to invoke the tool correctly is present.

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% and the single parameter is fully documented as 'City name or lat,lon'. The description repeats the parameter and provides concrete examples ('Tokyo', '35.68,139.69'), but this adds only marginal clarity 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?

States a specific verb 'resolve' and resource 'city name or coordinates to IANA timezone', and lists the exact return fields (current local time, UTC offset, DST flag, weekday). Scope is precise and unambiguous, distinguishing it from all siblings as the only timezone tool.

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?

Provides clear use cases: scheduling across regions, 'what time is it in X', and normalizing timestamps. No explicit exclusions or alternatives, but no sibling tool offers comparable functionality, so the guidance is sufficient for correct selection.

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