substitute

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

With no annotations provided, the description alone carries the burden of behavioral disclosure. It accurately describes the swap action but does not mention side effects, reversibility, permission requirements, or any validation rules. It is neither misleading nor misleading, but lacks extra detail such as whether the change affects the current or future gameweeks.

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 succinct and well-structured: one clear sentence for the main action followed by an efficiently formatted Args section. Every word adds value, and the most critical information (what the tool does) is front-loaded.

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 swap operation with an output schema present, the description covers the essential action and parameters. It could add notes on edge cases (e.g., if the player is already in the XI) but is otherwise complete for an agent to invoke the tool correctly.

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 0%, but the description's Args block thoroughly explains each parameter, including the optional team_id. It fully compensates for the schema's lack of metadata, ensuring agents understand the purpose and expected values.

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 function: 'Swap a bench player into the starting XI and move a starter to the bench.' This specific verb+resource formulation distinguishes it from siblings like make_transfer, set_captain, etc., with no ambiguity.

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 provides clear context for when to use the tool—whenever a player substitution is needed—without explicitly naming alternatives or exclusions. While it doesn't reference sibling tools like make_transfer, the distinct purpose and parameter names make the intended use obvious.

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