Set agent model

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

Annotations already declare destructiveHint=false and idempotentHint=true. The description adds behavioral context beyond this: the change takes effect on the agent's next turn, and explicit frontier models require a paid plan. No contradiction with 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?

Two front-loaded sentences convey purpose, timing, and constraints with zero redundancy. Every sentence earns its place, and the description avoids repeating schema details.

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 2-parameter tool with strong annotations and full schema coverage, the description is complete. It covers what the tool does, when the effect occurs, and important plan restrictions. No output schema is needed for a setter.

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 description coverage is 100%, with both parameters documented. The description adds value by explaining the plan-scaled Auto default and the paid-plan requirement for explicit frontier models, enriching the model parameter semantics 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 opens with 'Change an agent's model' – a specific verb and resource that clearly distinguishes this from sibling tools like create_agent, invoke_agent, or delete_agent. It unambiguously states the tool's purpose.

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 useful context for when to use it: it applies to existing agents and takes effect on the next turn. The note about Auto (plan-scaled) and paid frontier models gives usage constraints. It does not explicitly name alternatives, but the context is clear enough.

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