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

Annotations declare readOnlyHint=true, so the tool is a safe read operation. The description adds context about being free, requiring no API key, and focusing on 2026 fantasy draft data. However, it does not reveal whether historical data or year-to-year comparisons are supported, nor does it discuss any rate limits or data recency (e.g., is ADP live?). With annotations covering the core safety profile, a score of 3 is appropriate.

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 two sentences with no filler. The first sentence states the action, inputs, and outputs. The second provides example natural-language triggers and bonus info (free, no key). Every phrase 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?

Given 3 parameters with full schema coverage, no output schema, and this being a comparison tool (not a mutation or complex workflow), the description is thorough. It could add a note about return format or an example excerpt, but the presence of example queries compensates. A score of 4 reflects this minor gap.

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 description coverage is already 100%, so the baseline is 3. The description goes beyond the schema by clarifying the default scoring format ('half_ppr'), that scoring overrides platform defaults, and that Underdog/DraftKings imply best-ball settings. This adds meaningful context for parameter choices.

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 compares 2-4 players side-by-side for a 2026 fantasy draft, listing specific outputs (projection, floor/ceiling, ADP, draft round, value flag, pick recommendation, best market value). This distinguishes it from siblings like 'player_outlook' (single player) or 'best_available' (overall rankings).

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 provides example queries for usage ('"<A> or <B> in fantasy"', '"who should I draft, <A> or <B>"', etc.), making it clear when to invoke this tool. Contradistinction is implicit via sibling names (e.g., not for single-player analysis, which is 'explain_player' or 'player_outlook').

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