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

Annotations already declare read-only, idempotent, and non-destructive. The description adds valuable context: it is a free-tier endpoint, returns only aggregated counts (not individual records), and explicitly states it is not a profitability claim. This goes beyond the structured 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?

The description is three focused sentences, front-loaded with 'Free-tier endpoint' and 'Returns'. Every sentence adds distinct information: what it returns, when to use it, and an important caveat. No filler.

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 is simple, with one optional parameter and no output schema. The description explains the return content (total graded/settled, games, sports, per-sport and top-market breakdowns) and the use case. Annotations cover safety. Complete for the tool's complexity.

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 schema covers 100% of the single parameter (days) with a clear description including range and default. The description merely echoes 'last N days' without adding additional semantics, so the schema carries the burden. Baseline 3 is appropriate.

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 what the tool does: returns aggregated counts of graded player props over a look-back window. It explicitly distinguishes this from other tools by noting 'aggregated counts only' and positioning it as a coverage proof, not a profitability claim.

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 gives a clear 'Useful for' context ('how much graded prop data does PropLine have, what's the coverage') and explicitly says it is never a profitability claim. It does not list alternative tool names, but the context is sufficiently clear to guide an agent.

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