Rendering capabilities

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

Annotations already declare readOnly, idempotent, non-destructive, and non-open-world, so the safety profile is covered. The description adds useful context beyond that: zero-auth requirement, no external side effects, and the fact that it returns a JSON capability contract.

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 with the trigger condition front-loaded, followed by safety posture and return shape. Every sentence carries information and there is no filler.

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 zero-param read-only tool, the description covers when to call it, that it is safe, and that it returns a JSON capability contract. Since no output schema exists, the return shape is only gestured at, which is the one minor gap.

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?

The tool takes no parameters, and the description correctly implies a parameterless invocation. Baseline of 4 for a zero-param tool is appropriate; there are no parameter semantics to clarify.

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 resource and outcome: returning a renderer capability contract so a host can choose WebGPU/WebGL/canvas/static fallbacks. It is clearly a capability-discovery tool, though it does not explicitly contrast itself with the nearby telos.rendering.research sibling.

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?

"Use when a host must choose WebGPU, WebGL, canvas, or static rendering fallbacks for Studio surfaces" gives a clear triggering condition. It lacks explicit when-not guidance or a named alternative tool, but the usage context is unambiguous.

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