List walls, lights and other canvas elements

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context beyond the annotations: it lists the exact element types returned, notes that results include 'ids and their main fields,' and highlights the unusual ability to work without a drawn canvas. No contradictions with annotations.

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?

Three short sentences pack in the resource scope, filtering options, and an important edge-case cue. Every sentence earns its place, and the core action is front-loaded.

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?

The description is complete enough for a 7-parameter read-only tool with no output schema. It communicates element types, summary vs. raw data is implied by the raw parameter in the schema, filtering dimensions, and the 'works without a drawn canvas' behavior. It could be more explicit about pagination and the exact return shape, but the schema covers parameters and the summary field note is adequate.

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 fully documents all seven parameters. The description adds a helpful summary of filter semantics (type, area in pixels, doors only) that maps to elementTypes, bounds, and doorsOnly, but does not provide parameter-level detail beyond what the schema already contains. Baseline 3 is appropriate.

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 ('List') and a well-defined resource: canvas elements of a scene, enumerating wall, light, sound, region, tile, and drawing types. It clearly distinguishes from sibling mutation tools (create/update/delete-canvas-elements) and the view tool (get-canvas-view). The added context 'Works without a drawn canvas' further clarifies the tool's scope.

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?

Provides clear context on when the tool is appropriate by listing filtering capabilities and noting that it works without a drawn canvas eligibility. Does not explicitly name alternative tools or exclusion conditions, so it misses the top score but is still well above average guidance.

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