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

Annotations already indicate readOnlyHint=true, but description adds context: all quotes are indicative, and lists the return fields (guardType, guardRate, etc.). No contradiction with annotations.

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 front-loaded with purpose and workflow guidance, followed by a list of return fields. No redundant words; every sentence adds value.

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?

Despite no output schema, the description enumerates all return fields and states quotes are indicative. It also provides context about calling a sibling tool. For a pricing tool with 6 params, this is complete guidance.

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% with clear descriptions for all 6 parameters. Description adds extra value by explaining the optional 'guardRate' can be used for a fixed strike and giving workflow guidance, going 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?

The description clearly states it prices a 'Guard' — an FX protection product. The title 'Price a Guard' and description specify the exact verb and resource. Sibling tools like 'price_guard_extension' and 'resolve_settlement_date' are differentiated.

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?

Explicitly instructs to call 'resolve_settlement_date' first if a tenor is given, then use this tool. This provides clear when-to-use guidance and references a sibling tool, aiding correct sequencing.

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