Switch Model or Thinking Level

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

Annotations already declare this is a non-read-only, idempotent, non-destructive state change; the description usefully adds that no chat turn is triggered. It does not say whether the switch persists across later calls, whether omitted parameters are left unchanged, or what the response reports.

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?

One short sentence, front-loaded with the primary action and qualified with the key constraint. Nothing superfluous.

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?

With zero required parameters and no output schema, the definition should clarify whether both optional parameters can be set together and what a call with no parameters does. Those behaviors are left unstated, which is a meaningful gap for a two-optional-param state-changing tool.

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% and both parameters have enums, so the schema carries the parameter documentation. The description repeats four model names already in the enum but adds no guidance on defaulting, combining model and thinking_level, or calling with neither parameter.

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?

States a specific verb+resource ('switch the active model') plus a second capability ('adjust thinking level'), and enumerates the model names. The clause 'without sending a chat message' distinguishes it cleanly from the gemini_chat sibling.

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 phrase 'without sending a chat message' implies the selection condition: use this when you only want to change model or thinking level, and use gemini_chat when you actually want a response. It stops short of naming gemini_chat explicitly or stating what happens if both parameters are supplied.

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