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

Annotations already establish readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description complements this by revealing what the comparison covers (the decision fields), which is useful behavioral context beyond the annotations. 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, no filler. The core behavior and fields are front-loaded, and the usage guidance is compactly appended. Every sentence earns its place.

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, single-parameter tool with an output schema and rich annotations, the description is complete enough: it states what is compared, which fields matter, when to use it, and which sibling to avoid. No critical information 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?

Schema coverage is 100% and there is only one parameter (tickers), so the schema carries the main burden. The description's 'two or more instruments' aligns with minItems=2 and adds mild semantic color, but it does not add new parameter-level detail 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 states a specific verb ('Put ... side by side') and resource ('instruments') and enumerates the comparison fields (yield, risk, minimum, etc.). It differentiates from get_product_details by naming it as the alternative, but it does not distinguish itself from the other compare_* siblings like compare_tokenized_access or compare_with_savings_account.

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 description explicitly gives a usage trigger ('X vs Y' questions) and names get_product_details as the inferior alternative. It lacks when-not-to-use guidance relative to the other comparison-focused siblings, but the main routing information is clear.

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