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

Annotations already establish readOnly, idempotent, non-destructive and closed-world, so safety needs no restating. The description adds a genuine behavioral trait beyond that: the no-league-ID path degrades to a league-list/selection mode. It still does not mention auth, rate limits, or result size.

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 sentences, zero filler, with the primary capability front-loaded and the fallback mode second. Nothing redundant, though it is slightly clipped for a tool this data-rich.

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?

No output schema exists, so the description carries the return-value burden, and it does list the four things returned (standings, gap to leader, captains, differentials). With only two optional params and annotations covering safety, the main omissions are scope/pagination and any hint of the odds sibling.

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% and both parameters are documented in the schema, including the 'leave empty' semantics and link parsing, so the schema does the heavy lifting. The description's 'without a league ID' sentence largely repeats the schema's league_id note rather than adding syntax or format detail.

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?

States a specific resource (FPL mini-league) and enumerates what it returns: standings, gap to the leader, rivals' captains and differential picks. An agent can tell this is a standings/insight tool. It does not explicitly distinguish itself from the sibling get_mini_league_odds, which is the one plausible confusable tool.

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?

Gives one useful usage rule: omit the league ID to list the manager's leagues and choose from them. That is a conditional entry path, not when-to-use guidance against alternatives, and no exclusions or sibling routing are provided.

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