cbm_calculator

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

The description goes well beyond the annotations by disclosing determinism, the exact calculation formula, validation behavior for missing or non-positive dimensions, the 429 rate-limit contract with retry_after_seconds and Retry-After header, and the response fields. This is valuable operational behavior that annotations do not provide.

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 structured in clear sections — purpose, behavior, returns, related tools — with each sentence contributing useful information. No filler or redundant restatement of structured metadata appears, and the core purpose is front-loaded.

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, idempotent calculator with fully specified parameters and an output schema, the description covers the result payload, error behavior, rate limiting, retry handling, and alternative tools. No important invocation-related detail is missing.

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?

The input schema already provides 100% documented parameter coverage, including descriptions, examples, and value constraints. The description adds helpful context about per-piece dimensions and linear scaling, but the schema is already doing the heavy lifting, so the baseline score of 3 is appropriate.

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?

Opens with a clear verb-resource action: 'Calculate cubic metres (CBM) for a shipment from per-piece dimensions' — then situates it in the shipping domain and distinguishes it from related tools. The purpose is specific and not merely a restatement of the tool name.

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 'Related' section explicitly names alternatives with their distinct use cases: chargeable_weight_calculator for air cargo billing weight, consignment_calculator for multi-line totals, unit_converter for single conversions, and shipment_summary for full composite analysis. This gives an agent concrete guidance on when to choose this tool versus a sibling.

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