Save default fantasy team

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

Annotations already indicate the tool is neither read-only nor destructive, so the description's added context that it 'stores local identifiers only and does not call Yahoo' provides valuable extra transparency about network behavior and side effects. This goes beyond the annotations and helps the agent understand the tool's actual impact.

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 two sentences with no filler. The key facts are front-loaded: the action, the resource, and the crucial behavioral clarification about not calling Yahoo. Every sentence earns its place.

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 local save operation with no output schema, the description covers purpose, data source, and network behavior. It doesn't discuss overwrite behavior or failure modes, but the low complexity and rich schema/annotations make this sufficient for effective use.

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?

All four parameters have descriptions in the schema (100% coverage), so the description doesn't need to repeat them. It adds the context that identifiers come from the signed-in browser, but doesn't provide additional syntax or format details beyond what the schema already documents.

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 specifies the action ('Save') and the resource ('a Yahoo league and team discovered from the signed-in browser'), and distinguishes from sibling tools by noting this stores local identifiers only and does not call Yahoo. This makes the tool's purpose unambiguous and differentiates it from the analysis/query siblings.

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 implies a clear use case: when the agent has identified a Yahoo league/team in the browser and wants to persist it as the default. It doesn't explicitly state when not to use it or name alternatives, but the context provided is sufficient for an agent to infer appropriate usage.

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