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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is fully covered elsewhere. The only extra behavior the description adds is the word 'stable' - implying ids persist across calls - which is genuinely useful for caching/chaining but is never explained; nothing is said about result shape, paging via cursor/limit, or empty-result behavior on a tool with explicit pagination parameters.

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?

It is a single front-loaded fragment with zero wasted words, which is good structure. However, brevity here crosses into under-specification: the tool takes 7 parameters including a required user_request and a cursor-based pager, and none of that complexity is acknowledged in even one additional clause.

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 7-parameter search tool with no output schema, this description is far too thin. The agent cannot learn from it how results are ordered, whether person_key collapses split-league rows, or how cursor paging interacts with the 'stable ids' promise, and there is no output schema to fall back on.

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 each of the 7 parameters is already documented in the schema; baseline is 3. The description does map its three named axes onto search/league/team, giving mild orientation, but it says nothing about the interaction between them, about limit/cursor paging, or about person_key for cross-league identity - all of which live only in the schema.

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 fragment 'Stable player ids by name, league or team' names the resource (player ids) and the lookup axes, so an agent can infer it resolves players to canonical ids. But there is no verb and no differentiation from siblings like 'search', which would plausibly handle the same name lookups; the agent must guess which is authoritative for player identity.

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?

No when-to-use guidance, no exclusions, and no mention of when to prefer this over 'search' or the projection/game-log tools that also take players. The agent gets an implied 'use this to find players' and nothing more, so routing between this and 'search' is left to inference.

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