Finish authorization with a code

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

The description adds value beyond annotations (readOnlyHint: false) by detailing side effects: it lists the user's leagues and automatically sets a default if only one league exists. This provides clear behavioral expectations for the agent.

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 extremely concise: two sentences covering purpose, optional parameters, and side effects. Every sentence is information-dense and necessary, with no wasted words.

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?

Given the tool's moderate complexity (3 optional params, no output schema), the description adequately covers the key outcome (listing leagues and setting default). It lacks explicit mention of error cases or return format, but the behavioral outcome is sufficiently described for the agent to understand what happens on success.

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% with detailed descriptions for all three optional parameters. The description summarizes the optionality of clientId/clientSecret but does not add new parameter meaning beyond the schema. The code parameter's schema already includes the 'leave blank' instruction, so the description is largely redundant.

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 states the tool's purpose: completing authorization using a verification code from Yahoo after user approval. It distinguishes from siblings like fantasy_login by specifying it is for finishing the setup, and mentions optional credentials and side effects.

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?

It explains when to use the tool (after user approves access and a code is displayed) but does not explicitly mention when not to use it or alternative tools. The sibling context implies it's the final step after fantasy_login, but explicit guidance on alternatives would improve clarity.

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