HIP-4 Cross-Product Overlap

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

Annotations already cover read-only, idempotent, open-world, and non-destructive behavior. The description adds valuable context beyond these by stating the Pro-or-higher key requirement and summarizing the returned counts. This auth constraint is important for an agent deciding whether the tool is callable in the current context.

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 three sentences with no filler. It front-loads the core purpose, then lists the key returned values, then states the access requirement. 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?

The tool has only two optional parameters, and both are fully documented in the schema. The description covers the output semantics, the access requirement, and the cross-product scope clearly enough. Since no output schema exists, the description's mention of returned counts and percentage provides the needed return-value context.

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 documents both parameters, including defaults and constraints, at 100% coverage. The description does not add much parameter-specific meaning beyond the schema, but it does clarify that the tool is window-based and returns overlap-related counts, which aligns with the 'days' parameter.

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 ('Measure overlap') and a precise resource combination: HIP-4 outcome traders versus perp traders. The tool name and description together clearly distinguish it from sibling tools like pulse_compare or builder_overlap, since the cross-product scope is explicit.

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 intended use is implied: an agent can infer this tool is appropriate when overlap metrics between HIP-4 outcome traders and perp traders are requested. However, the description does not explicitly state when to prefer this tool over related siblings or provide exclusions, leaving some routing ambiguity.

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