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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed-world scope, so safety is covered. The description adds information annotations do not carry: a concrete cost of 2 credits, plus the fact that results are returned newest-first and include the first meeting. It does not mention rate limits or auth, which keeps it below a 5.

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?

A single sentence that front-loads the triggering scenario and then lists the returned content, with no filler. The credit cost is appended compactly at the end where it is easy to scan.

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?

With an output schema present, the description needn't explain return values, yet it usefully flags the newest-first ordering and the credit cost. Combined with 100% schema coverage and rich read-only annotations, an agent has what it needs to call this correctly. Only the lack of sibling disambiguation keeps it from a 5.

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 team, opponent, league and limit are already documented in the schema, including the note that the summary counts every meeting regardless of limit. The description only reinforces the two-club framing and the league scoping ("this competition") without adding format or identifier guidance. 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 names a specific resource (two clubs' head-to-head meetings in a competition) and enumerates what the result contains: wins, draws, goals each, first meeting, newest-first ordering. That is far more specific than the name alone. It stops short of distinguishing itself from siblings such as get_game or get_team_stats, but the purpose is unambiguous.

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 for two clubs' meetings in this competition" is a positive usage directive, so the agent knows the triggering scenario. However, there is no statement of when to prefer get_game, get_events or get_team_stats instead, and no prerequisites or exclusions. Usage is implied by scenario rather than explicitly routed.

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