set_color_xy

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

Annotations already declare idempotent=true, destructive=false and readOnly=false, so the safety profile is covered; the description adds only the 0-1 range of the coordinates. It says nothing about targeting behavior, what happens if the light does not support xy color, or error behavior for plugs/white-only bulbs — meaningful gaps for a state-changing tool.

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 front-loaded sentence with no filler, and the coordinate range is placed immediately after the key term. It is efficient but arguably too terse, since nothing follows to cover targeting or capability caveats.

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 four-parameter mutation tool with zero schema description coverage, the definition leaves the light-targeting semantics (two optional, string-defaulted identifiers) unexplained. Return values are covered by the output schema, so that omission is fine, but the input-side ambiguity and missing color-capability caveat keep this well short of complete.

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% across four parameters, so the description must compensate, and it only partly does: it clarifies that x and y are fractional CIE coordinates in 0-1. The two targeting parameters (light_id, light_name — both defaulting to empty string) get no explanation of precedence or what an empty pair means.

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 ('Set') and resource ('a light's color') plus the exact color space (CIE 1931 xy), which implicitly separates it from set_color_rgb, set_color_temperature and set_color. It stops short of naming those siblings explicitly, but the coordinate-space detail is enough for an agent to tell them apart.

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?

Nothing states when to prefer xy over RGB, temperature, or the generic set_color sibling, nor any exclusion such as lights that do not support color. The agent is left to infer selection entirely from the coordinate system mentioned.

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