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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds substantial context beyond them: asOf timestamps, source attribution, grade semantics, and explicit caveats that revenue is an estimate range, never measured sales. It also warns which metrics are cross-platform comparable. It stops short of describing pagination or response shape, but the output schema covers returns.

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?

Front-loaded with the core purpose, then caveats and definitions. Dense but each clause carries information; the grade-definition parenthetical is long but genuinely useful. Slightly heavy for a one-parameter tool.

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 comparison tool with a full output schema, the description covers scope, comparability caveats, data provenance, and confidence grading. An agent has everything needed to call it and interpret results correctly.

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% and the schema already documents accepted id formats and the 2-4 bound, so the description adds little new parameter meaning. Baseline 3 applies 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 and resource ('side-by-side records of 2 to 4 games') and enumerates the compared fields (players, momentum, reviews, age, revenue, complaints). The reference to 'same fields as get_game' implicitly distinguishes it from the single-game sibling.

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 2-to-4 game scope implies when to use it, but there is no explicit when-to-use/when-not guidance and no named alternative (e.g., get_game for a single title, analyze_niche for market-level comparison). Usage is inferable rather than stated.

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