renderer_info

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so 'Read-only' is largely a restatement of structured data. The description does add value by naming the returned contents (draw calls, triangles, memory, capabilities) and the backend distinction, but says nothing about cost, rate limits, or snapshot timing beyond that.

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?

Two compact lines with the key content front-loaded and zero filler sentences. Minor redundancy in restating 'Read-only' where annotations already cover it, which keeps it just short of a 5.

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 no output schema, the description carries the return-value burden and does so adequately by enumerating the data categories and the backend variants. The safety profile is fully covered by annotations, so nothing an agent needs to select or call this tool is missing.

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, so per the rubric this is the baseline. There is nothing for the description to disambiguate, and it correctly avoids inventing parameter semantics.

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 ('Renderer stats and backend') and enumerates what it returns (draw calls, triangles, memory, capabilities), plus the WebGL/WebGPU backend dimension. It is distinguishable from write-oriented siblings like set_renderer, but it does not explicitly differentiate itself from overlapping read tools such as draw_call_breakdown, memory_stats, or performance_snapshot.

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?

The '[INSPECT] Read-only' tag implies inspection use but gives no explicit when-to-use guidance, no conditions, and no pointer to the many overlapping sibling tools (draw_call_breakdown, memory_stats, performance_snapshot). The agent must infer the selection criteria itself.

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