add_light

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

With no annotations, the description carries the full behavioral burden and does so richly: it explains create-vs-update semantics ('same name updates that light; it never makes a copy'), default placement for omitted location/look_at, preservation of omitted fields on update, power/color/temperature semantics, shape-specific constraints, and name restrictions. This is comprehensive for a mutation 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?

It is a dense but front-loaded paragraph; the first sentence states purpose and the main alternative, then each subsequent sentence explains a distinct parameter group. The length is justified by 13 parameters, though bullet formatting could improve scanability.

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 13-parameter mutation tool with no annotations and no output schema, the description covers what an agent needs: creation/update behavior, defaults, constraints, naming rules, and practical guidance. Return values are not described, but none are provided in an output schema, so completeness is high.

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 13 parameters, so the description must compensate, and it does: it defines kind, location (world metres), look_at aim point, power_w units and practical wattages, color formats, temperature_k range/effect, spot_size_deg range, blend range, cutoff_m, radius source size, size area dimensions, and shadow_soft. Nearly every parameter receives meaningful semantics beyond its type.

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 starts with a specific verb+resource ('Create or update one light') and immediately distinguishes it from the sibling setup_lighting ('makes a whole preset instead'), so an agent can select it without opening other tools.

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?

It explicitly names when to use an alternative ('setup_lighting makes a whole preset instead') and when not to use it ('Names that start with bl_light_ belong to setup_lighting and are refused'), plus points to delete for removal. This gives clear routing guidance.

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