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

Annotations already cover read-only, idempotent, closed-world and non-destructive behavior, and the description adds the useful negative capability (no win chance) plus the Desk Pass dependency for the alternative. It does not say what happens when all three optional parameters are omitted, which is a meaningful gap given zero required params.

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 what is returned, then usage, then the exclusion — a sensible order with no filler. The trailing Desk Pass explanation is slightly more than the routing need requires.

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 lookup with no output schema, the description covers return shape, intent routing, and the alternative tool for win probability. The only material omission is the behavior when no team or player is supplied, which matters because no parameter is required.

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%, so the baseline is 3, but the description adds routing meaning not present in the schema: team vs player selection depends on whether the ask is about a named team or is first-person. It does not clarify the role of `asked` beyond what the schema already says.

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 verb and resource (returns a team's or player's upcoming matches) and enumerates the returned fields (opponent, day, start time, home/away). It also carves out a boundary against project_standings, so the agent can distinguish it from the forecast/standings siblings.

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?

It gives concrete triggering phrasings ('next match', 'today's or tomorrow's match', 'the schedule') and routes parameter choice by intent: team for a named team, player for a first-person ask. It also states explicitly what it does not answer (team win chance) and names the tool that does, project_standings.

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