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

The description goes beyond annotations by characterizing the tool as a raw gateway that relays the league app's response, implying pass-through behavior with no interpretation. It also discloses the 1 MESH/call cost and gives examples of mutating calls like set_lineup and trades, which is useful context for a non-read-only tool.

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 compact and front-loads the core purpose ('Raw gateway') before giving examples and usage constraints. The opening repeats the tool title and the trailing 'a tool · sports' adds little, but most sentences carry meaningful information.

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 single-parameter pass-through gateway with no output schema, the description adequately covers protocol, example methods, intended audience, cost, and the fact that responses are relayed from the league app. It does not specify a full JSON-RPC request shape, but the 'already know the contract' framing makes that a reasonable omission.

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?

Although the schema has 100% coverage, its 'input' property description is a generic placeholder with irrelevant agent-brain/agent-memory examples. The tool description compensates by explaining that the input should be a JSON-RPC request body and by naming realistic methods such as tools/list and tools/call, adding essential 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 description clearly identifies this as a raw gateway into a private fantasy-football MCP server that accepts JSON-RPC request bodies and relays responses. It names concrete operations (get_standings, get_roster, set_lineup, trades, weekly processing) and explicitly separates itself from plain-language lineup advice, making its purpose and scope unmistakable.

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 gives clear context: it is for agents that already know the fantasy-mesh MCP contract, not for users wanting plain-language lineup advice. It provides examples of valid calls, but it does not name a specific alternative tool for the excluded plain-language use case.

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