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

Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, so safety is covered. The description adds genuinely useful material beyond that: the return payload shape (matchups with a win/loss record) and a non-obvious cost signal ("Costs 10 credits") that affects whether an agent should call it.

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?

Three short sentences with zero padding: the trigger condition leads, the return value follows, and the cost warning closes. Every sentence contributes information an agent needs before calling.

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, five-parameter tool with a full output schema, the description covers the trigger, the filter modes, the result shape, and the credit cost. Nothing material is missing, and return-value detail is appropriately left to the output schema.

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 100%, so the schema already documents team abbreviations, the league enum, the 8-digit season format, and the limit default/range. The description only restates the season filtering option ("filter by season or get all-time"), which the schema's season description already conveys. Baseline 3 applies.

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 states a specific verb+resource combination — comparing two teams' head-to-head history — and names the output (recent matchups with win/loss record). This is clearly distinct from siblings like get_games (all games) or get_team_stats (single-team aggregate), so an agent can select it without opening the 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?

"Use when comparing two teams' history" gives explicit context for invocation, and "Can filter by season or get all-time" clarifies the two modes. There are no explicit exclusions or named alternatives, but no sibling provides head-to-head matchup data, so the routing risk is low.

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