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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds the comparison axes (yield, risk, custody, KYC gates, etc.), which is genuine behavioral context about what the output emphasizes, though it does not mention the six-instrument cap.

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 dense sentences with zero filler, and the comparison scope is front-loaded before the alternative-call guidance.

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?

With an output schema, annotations, and a fully documented single parameter, the definition gives an agent everything needed to invoke it. The only unwritten detail is the maxItems=6 limit, which the schema already enforces.

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% and the schema even supplies a format example, so the single parameter is fully documented structurally. The description's 'two or more instruments' restates minItems=2 and adds no syntax beyond the schema, so baseline 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 (compare/put side by side) and resource (instruments) and enumerates the exact fields compared, so the agent knows precisely what it returns. It is clearly distinguishable from siblings like get_product_details or compare_tokenized_access.

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 names the trigger ('X vs Y' questions) and the alternative to avoid ('instead of calling get_product_details repeatedly'). This routes the agent correctly without any inference.

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