set_output_pin

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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the accepted value range (0–1) and model-specific pin names, which is real context. It does not state what happens for an unknown pin name or other printer models, or whether the state persists across restarts.

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 short sentences, front-loaded with the action and its argument shape, with no filler. The trailing discovery hint is the only slightly detachable element, but it earns its place for a name-keyed parameter.

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?

An output schema exists, so return values need no explanation, and the annotations cover safety and idempotency. For a small mutation tool the essentials are present, but the missing guidance on choosing between this and its dedicated siblings, plus no error behavior for bad pin names, leaves an agent guessing at the edges.

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% — both properties are bare 'string' and 'number' with no titles beyond the key names — so the description must carry the semantics, and it largely does: 'pin' is a name with three concrete Max4 examples, and 'value' is constrained to 0–1. Case sensitivity of names and the behavior of out-of-range values are left unstated.

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?

Names a specific verb and resource ("Set one of the printer's output pins") and immediately qualifies it with the two inputs, name and 0–1 value. The enumerated Max4 pins ('caselight', 'beeper', 'Polar_cooler') make the resource concrete. It stops short of distinguishing itself from siblings that do the same job (set_case_light, beep, set_polar_cooler).

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?

"Use list_devices to see what exists" gives a useful discovery path when the pin name is unknown. However, it never says when to prefer this generic tool over the dedicated siblings set_case_light, beep, and set_polar_cooler, which appear to target the exact pins named here — a significant routing gap 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.