Fill a room with light

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

Annotations already declare a non-read-only, non-destructive, non-open-world mutation. The description goes further by explaining the placement mechanism, the termination condition, and what is returned (placed ids plus the room's rating before and after) — meaningful behavior beyond the annotations. It does not discuss reversibility or idempotency, but destructiveHint=false plus the reported ids cover the main risk surface.

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?

It is a single dense sentence (plus a short follow-up on the reply), front-loaded with the action and the fixture enumeration. Every clause earns its place, though the semicolon-linked structure is slightly run-on.

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?

With a full output schema and annotations covering the safety profile, the definition only needs to convey the mechanism and the target-setting behavior. It does that, plus notes the rating before/after. Adequate and complete for a four-parameter mutation tool.

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 all four parameters, and an output schema exists. The description clarifies that `lux` overrides the room reference and enumerates the valid `fixture` values, but this largely restates the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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 gives a specific verb (fill), resource (a room with a grid of one fixture), the fixture options, and the termination condition (work plane reaching the ABNT/CIE reference or a given lux). That is far more concrete than the tautological title. It references the sibling `lighting` only as the photometry engine it shares, not as an alternative to choose between, so it stops short of a clean sibling differentiation.

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 implied: this is the tool that auto-places a grid of fixtures to hit a target illuminance. There is no explicit statement of when to use it versus `lighting` (inspection) or `edit_electrical`, and no prerequisites or exclusions are given. The relationship to `lighting` is noted but not framed as a routing decision.

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