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

Annotations already establish read-only/idempotent/non-destructive, so the bar is low; the description still adds real substance by enumerating the computed outputs and defining the scope boundary (equal-share math, no goalkeeper adjustments). It doesn't mention error or edge-case behavior, but the boundary statement is meaningful added context.

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?

Two tight sentences, front-loaded with the computed outputs and closed with the scoping caveat. No filler or repetition of the title.

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?

An output schema exists, so return values needn't be explained, and the annotations cover the safety profile. The gap is that with 0% parameter coverage, nothing in the description compensates for the undocumented format/rosterSize/gameMinutes inputs.

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 0%, so the schema gives only types, ranges, and one enum with no explanation. The description never mentions format (7v7/9v9/11v11), gameMinutes, or rosterSize, so the agent gets no help on what the format enum means or how roster size interacts with bench size.

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?

Specific verb (calculate) plus resource (playing time) and an explicit enumeration of outputs: minutes, percentage per player, bench size, segment length, and 50% minimum check. The closing clause hints it differs from generate_fair_lineup by excluding goalkeeper constraints, though it doesn't name that sibling directly.

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 phrase 'before any goalkeeper constraints' implies a sequencing relationship with lineup/constraint siblings, but there is no explicit statement of when to call this instead of generate_fair_lineup or recommend_formation. Usage is inferable but not spelled out.

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