get_brightness

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

readOnlyHint=true already declares this is a safe, non-mutating read, so the bar is lower. The description adds the return semantics ('as a percentage') and scopes the target to the built-in display, which is real value beyond the annotation since no output schema exists to convey the format.

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?

A single front-loaded sentence with zero filler; every clause (verb, target, unit) 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?

For a zero-parameter read with no output schema, the description covers what is returned and in what unit, which is the key missing piece. It stops short of noting edge cases such as a machine with no built-in display, but nothing essential to invoking it correctly is absent.

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?

The tool takes zero parameters, so per the rubric the baseline is 4. There is nothing to disambiguate and the description correctly introduces no parameter discussion.

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?

States a specific verb (Get) and resource (built-in display's brightness) plus the return unit (percentage), so the agent knows exactly what it retrieves. It doesn't explicitly name the sibling set_brightness as its counterpart, but the get/set split against that sibling is 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?

Usage is only implied: an agent can infer this is a read used to inspect the current brightness, likely before calling set_brightness. There is no explicit when-to-use statement, no prerequisite, and no alternative named, so it stays at minimum viable.

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