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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering safety and dynamism. The description adds valuable context beyond that: it discloses the tool is 'Live in-season (opens NFL Week 1)' (availability) and requires a 'Pro key' (auth). It also clarifies the return content. This meaningfully enriches what annotations provide, without contradiction.

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 information-dense but each sentence earns its place: it starts with the core function, lists outputs, then states availability/auth, and ends with search-phrase examples. It's not overly long, and the most critical information (purpose) is front-loaded. Minor redundancy: the list of stat types appears in both the first sentence and the propType enum, but that adds clarity.

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 data-fetch tool with only three optional parameters and no output schema, the description covers what an agent needs: the comparison logic, output fields, availability, auth, and usage examples. It lacks explicit mention of data freshness guarantees or edge definitions, but given the simplicity and the annotations, it is sufficiently complete for correct invocation.

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% — all three parameters (limit, minEdge, propType) are documented with descriptions and defaults already. The tool description does not add any parameter-level detail beyond the schema; it mentions 'edge' in the output but not in relation to the minEdge param syntax. Baseline 3 applies because the schema fully covers parameter meaning.

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 clearly states the tool's purpose: it computes NFL player-prop edges by comparing the PredictionMarketsPicks projection against the Kalshi line for specific stat types (passing/rushing/receiving yards, receptions, anytime TD). It names the output fields (model projection, probability, Kalshi price, edge, side) and the specific resource ('player-prop edges'), distinguishing it from broader siblings like nfl_edge or nfl_power_ratings.

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?

Provides example queries ('NFL player prop edges', 'best NFL props today', etc.) and notes it's 'Live in-season' and 'Pro key required', giving some usage context. However, it does not explicitly state when to prefer this over sibling tools (e.g., nfl_edge) or when NOT to use it. The guidance is implicit through the prop-specific framing, but no exclusions or alternatives are named.

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