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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so safety is covered. The description adds value beyond that: the required League Read role and the fact that results are paged (with the schema's next_page convention). It stops short of describing ordering or what an empty page means, but the additions are substantive.

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?

Four short clauses with no filler: scope first, then paging, then auth, then the endpoint. The telegraphic style makes it slightly choppy, but every element earns its place and the most important scoping constraint is front-loaded.

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 no output schema, the description does the necessary work by naming the return payload (sessions plus optional game days and players), the paging behavior, and the auth requirement. The only gap is that the mutual exclusivity or nesting logic between league_id and session_id is left to the schema wording.

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 all six parameters including page/page_size defaults and the include_players caveat ('use with one session') are already documented. The description only echoes the include options at a high level and adds no format or interaction detail beyond the schema, so the baseline of 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?

Names the resource (league sessions) and its scope precisely: 'for one league or one session, optionally with their game days and registered players.' It is a noun-phrase fragment rather than a verb+resource sentence, but the resource and what is returned are unambiguous. It implicitly distinguishes itself from courtreserve_list_leagues by dealing in sessions, though it never names that sibling.

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 prerequisite 'Needs the League role (Read)' is real usage guidance, and the id-scoped phrasing ('for one league or one session') implies the filtering choice. However there is no explicit statement of when to use this instead of courtreserve_list_leagues or of any exclusion, so the agent must infer the routing.

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