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

The annotations already mark the tool as read-only, idempotent, and non-destructive, but the description adds a crucial behavioral fact: the setup is sealed into the token and only changes via /setup plus reconnect. It also warns against instructing users to remove the connector, which prevents a harmful action the annotations alone would not reveal. There is no contradiction with the annotations.

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?

The description is long but every sentence earns its place: purpose, trigger phrases, token-sealed behavior, no-credentials rule, and replacement context. The purpose is front-loaded in the opening sentence, so an agent can classify the tool immediately without wading through caveats. The length is justified by the behavioral cautions it conveys.

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 simple read-only setup tool with one optional argument, the description covers the output concept (leagues, teams, add/remove steps), when to invoke it, and the essential token-reconnect caveat. There is no output schema, but the response_format parameter lets the agent choose markdown or JSON output. Nothing an agent needs to call it correctly is missing.

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?

The only parameter, response_format, is already fully described in the schema with an enum, default, and description, so schema coverage is 100%. The description's 'No arguments needed' is consistent but redundant given that required parameters are 0 and the default is documented. The description adds no real meaning beyond 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 first sentence names a specific verb and resource: it 'shows' the 'leagues and teams configured in the connected profile'. The '(whoami)' framing and the mention of add/remove setup steps separate it from live-data siblings like fantasy_get_my_teams or fantasy_get_league_info. The scope is unambiguous even without naming a 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 description explicitly says to call this tool FIRST in a personalized session and maps concrete user triggers ('I also have an ESPN league', 'I started a new league', 'update my teams') to it. It also gives a firm negative rule: never tell the user to remove the connector. This is strong, actionable when-to-use guidance.

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