frame_timing

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

Annotations already establish readOnly and idempotent behavior, but the description adds substantial context beyond them: the full returned field set, the cpu_busy_ms formula, the nullrhi/commandlet edge case where timings read 0 and verdict becomes no-data, and the role of note. This is rich behavioral disclosure.

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?

The description is front-loaded with purpose followed by a structured Returns block. It is dense and somewhat lengthy, but since no output schema exists, the detailed return documentation earns its space.

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-parameter, read-only diagnostic tool with no output schema, the description fully documents the returned structure, verdict enum values, edge-case behavior, and the meaning of derived fields. Nothing needed to interpret or call the 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 zero parameters, so there are no inputs to explain and the baseline is 4. The empty schema is fully consistent with the description, which correctly requires no arguments.

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 (read) and resource (current frame's Game/Render/GPU/RHI thread times) plus the key output (CPU-vs-GPU bottleneck verdict). No sibling in the list provides this exact profiling read, so the purpose is unambiguous even without naming an alternative.

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?

Usage is implied—this is a diagnostic read for frame timing—but the description does not explicitly say when to call it versus alternatives such as get_fps_info or get_engine_stats. There is no when-not or alternative routing guidance.

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