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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: it discloses the shape of the returned comparison (strikes, best price per side across venues, probability where published, ranked verdict), which matters because there is no output schema. It omits auth/rate-limit details, keeping it at 4.

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 output summary is front-loaded in a single dense sentence, followed by an immediately actionable 'Use for' set of examples. It is slightly long but every clause (outputs, then trigger phrases) 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 small 3-parameter, no-output-schema tool, the description supplies the return-value picture an agent would otherwise lack and covers the temporal scope. The scoring/platform parameters are left entirely to the schema, but that is acceptable given full description coverage there.

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 the schema already documents players, scoring and platform. The description reinforces the 2–4 player bound and the 'this week' temporal scope but adds no syntax or format detail beyond the schema. Baseline 3 is correct when the schema does the heavy lifting.

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), resource (2–4 NFL players this week) and enumerates exactly what the comparison returns: each Kalshi prop strike, best price per side across venues, model probability, and a ranked verdict. This is detailed enough that an agent can distinguish it from siblings like explain_prop or nfl_prop_edge without opening a schema.

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 'Use for' clause supplies four concrete query patterns ('<A> or <B> this week', 'compare <A> and <B> props', 'who has the better prop...', '<A> vs <B> receiving yards') that clearly map user intent to this tool. It stops short of naming a competing sibling as the alternative or stating when-not to use it, so it lands at 4 rather than 5.

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