Fill a room with light

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

The description discloses important behavior beyond the annotations: it places a grid of fixtures, evaluates the result using the same photometry as the lighting tool, and returns placed ids plus before/after ratings. It does not mention whether existing fixtures are removed or replaced, but the additive nature of 'fill' combined with destructiveHint=false gives adequate clarity.

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 compact and front-loaded: it states the action, target, fixture types, validation method, and output in two sentences. Every sentence adds meaningful information, and there is no redundant repetition of the title or schema.

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 moderate complexity, full schema coverage, and existing output schema, the description provides enough information to call the tool correctly. It explains the operation's scope, the photometry consistency, and the return content, leaving no critical ambiguity for an agent.

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 100%, so the schema already documents all parameters. The description adds useful context about the 'lux' parameter overriding the room's reference and the work plane concept, but it does not substantially enrich parameter semantics beyond what the schema provides.

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 a specific action ('fill a room with a grid of one fixture'), the exact fixture types allowed, and the goal (reaching the room's lighting reference or a specified lux value). It also distinguishes itself from the sibling 'lighting' tool by mentioning the same photometry check, making its purpose 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?

The description implies when to use the tool: when a room needs to be automatically filled with a grid of fixtures to meet a lighting target. However, it does not explicitly state when not to use it or which alternative (e.g., 'lighting' or 'place') should be chosen for manual or partial lighting setups.

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