set_engine

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

With no annotations provided, the description carries the full burden for behavioral disclosure. It mentions 'session-level' which indicates a state change, but it doesn't explain side effects, reversibility, or whether changing the engine affects ongoing operations. It also doesn't describe error conditions or permission requirements. This is a notable gap for a state-mutating tool.

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 extremely concise, fitting in two short sentences with no wasted words. The action is front-loaded, and the parameter guidance is immediately adjacent. Every clause 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?

Given the tool's simplicity (2 required params, no schema descriptions) and the presence of an output schema, the description covers the core purpose and parameter semantics. However, it omits behavioral context like side effects or session lifetime. With no annotations, this leaves the agent without full risk awareness, making it incomplete for a state-changing operation.

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%, so the description must compensate. It does by listing the allowed values for kind and explaining that name is obtained via catalog(). This adds meaningful meaning beyond the bare schema. It could go further by describing what each kind represents, but the current explanation is sufficient for basic usage.

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 action: switching a type of engine at session level. It enumerates the valid kinds (vad/asr/agent/tts), which immediately distinguishes it from sibling tools like speak or listen. The verb 'switch' plus the resource 'engine' is specific and unambiguous.

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?

It gives explicit guidance on valid kind values and tells the user to consult catalog() for the name parameter, implying a workflow. However, it doesn't explicitly state when to use this tool versus alternatives, or mention potential prerequisites like an active session. Still, the catalog reference provides a clear path for correct invocation.

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