set_brightness

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

Annotations already declare this is a write operation that is not destructive (readOnlyHint=false, destructiveHint=false), so the safety profile is covered. The description adds real behavioral context by restricting the hardware scope to the built-in display, but says nothing about persistence, reversibility, or permission requirements.

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 scope sentence followed by a single argument line; everything is front-loaded and nothing is padded. The Args block is slightly redundant with the schema but stays within one line.

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 single-parameter setter with no output schema and annotations covering the safety profile, the description supplies the two things an agent needs most: hardware scope and the valid value range. Only persistence/reversibility behavior is unaddressed.

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 description coverage is 0%, so the description must carry the parameter, and it does: 'level' is documented as an integer from 0 (darkest) to 100 (brightest), giving both range and direction. Only the unit (percent) is left implicit, which is a minor gap.

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?

Specific verb (Set) plus specific resource (the built-in display's brightness), with an explicit scope boundary that rules out external monitors. An agent can immediately distinguish it from the sibling get_brightness, which reads rather than writes.

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 one exclusion — external monitors aren't supported — which is genuine when-not guidance, but it never states when to prefer this tool or what an agent should do instead for external displays. Usage is implied rather than fully specified.

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