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

Annotations already declare readOnlyHint=true and openWorldHint=true. The description adds meaningful context: output fields (comparable, comparison_basis, rows, ranking, excluded_from_comparison, message), status meanings (UNKNOWN, NEEDS_MORE_DATA, MANUAL_REVIEW), and the caveat that a ranking is never an all-in landed-cost winner. 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?

Seven sentences, front-loaded with primary use case and sibling routing, then exclusions, output fields, status meanings, and a critical caveat. No filler; every sentence carries operational 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?

Complex comparison tool with no output schema, but the description compensates by enumerating output fields and status semantics, naming siblings, and giving explicit non-goals. The single parameter is thoroughly documented.

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%, so baseline is 3. The description adds value by clarifying each item may be a raw quote accepted by normalize_supplier_quote or an existing preflight_quote_passport, and the schema's own guidance on comparability reinforces correct usage.

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 and resource: 'compare 2–5 China supplier quotes' for a defined corridor and purchase stage. It explicitly distinguishes itself from siblings by saying when to use normalize_supplier_quote and trade_preflight instead.

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 says 'Use BEFORE choosing or paying a supplier', tells you to use normalize_supplier_quote for a single quote and trade_preflight for a shipment-level gate, and lists forbidden use-cases (freight marketplace, tariff classifier, customs brokerage, legal advice).

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