set_input

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

Annotations already indicate this is a mutation (readOnlyHint=false), idempotent, and non-destructive. The description simply restates the action of changing the input source; it adds no extra behavioral context such as whether the device must be powered on or how errors are reported.

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 a single clear sentence that front-loads the action and resource, followed by a parenthetical list of valid values. No filler or redundant content.

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 with one required parameter and no output schema, the description fully conveys the tool's purpose and valid values. There is no missing information needed to select and 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 100%, so the schema already documents the 'source' parameter. The description lists the same example values and adds no new meaning beyond confirming the valid set, which is also present in the schema's description.

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 uses a specific verb 'Change' with a resource 'la source d'entree' (input source) of the Denon, and enumerates the exact valid values (BD, TV, GAME, SAT/CBL, DVD, MPLAY). This clearly distinguishes it from sibling tools which handle volume, mute, power, and status.

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 a clear context: it is for changing the Denon's input source, and the sibling tools cover different functions (volume, power, mute). It does not explicitly name alternatives or exclusions, but the intended usage is unambiguous given the sibling list.

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