set_model

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

With no annotations provided, the description must carry the behavioral disclosure burden. It states the action ('set') but omits any side effects, persistence, session scope semantics, or whether changing the model affects existing conversations. The word 'session' hints at scope but lacks explicit detail, leaving the agent to infer the behavioral contract.

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 concise sentences. The first sentence immediately identifies the action and scope; the second adds necessary selection guidance. No words are wasted, and the structure 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 setter tool with full schema coverage, the description is mostly adequate. However, it lacks any mention of return value or confirmation, and without annotations it does not address persistence or side effects. Given the low complexity, this is a moderate gap; the description is complete enough to use but not fully self-contained.

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%, so the parameter semantics are already well-documented. The description adds value by clarifying the trade-off between 'flash' and 'pro' (speed vs. quality), which supplements the schema's enum descriptions. However, it does not mention the conversation_id parameter or its default, but since the schema covers that and the description's 'for this session' hints at it, a baseline score of 3 is appropriate.

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 verb ('Set') and resource ('the Gemini model for this session'), making the tool's purpose immediately obvious. It distinguishes itself from sibling tools like gemini_chat or gemini_generate_image by focusing on session-level configuration.

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?

Provides explicit guidance on when to choose each model value: 'flash' for faster generation and 'pro' for higher quality, which is directly actionable for the primary parameter. However, it does not explicitly mention alternatives like set_aspect_ratio or when not to use this tool, though that context is somewhat implied by the sibling set.

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