unreal_performance_start

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

Annotations are all false, so the description carries the burden of behavioral disclosure. It discloses that the capture is bounded (10..600 samples, 60-second limit), that it is a non-freezing editor ticker capture, and that it does not measure packaged gameplay FPS. It also indicates the operation is asynchronous by saying 'Poll by job id.' This is meaningful behavioral context beyond the schema and 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?

The description is three sentences with no wasted words. It front-loads the core action and bounds, then adds exclusions and the polling mechanism. Every sentence earns its place.

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 tool has an output schema and sibling tools that cover job status and cancellation, so the description does not need to explain return values. It covers the key constraints, exclusions, and async behavior. It could be slightly more complete by mentioning that the capture is tied to a protocol_id and expected_state, but the schema already defines those required parameters clearly.

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%, so the description must compensate. It explains the sample_count range (10..600) and the 60-second limit, which adds meaning to sample_count. However, it does not explain protocol_id or expected_state beyond what the schema provides. The schema already defines protocol_id as a string pattern and expected_state as an inspected editor state, so the description adds partial value but leaves the key parameters' semantics mostly to the schema.

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 clearly states the tool starts a bounded editor ticker timing/memory capture with specific sample and time limits. It distinguishes itself from related performance tools by explicitly noting it does not freeze the scene or measure packaged gameplay FPS, and mentions polling by job id, which aligns with sibling tools like unreal_performance_job and unreal_performance_cancel.

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 description provides clear context for when to use this tool: to start a bounded editor ticker capture while holding settings constant in a named protocol. It does not explicitly name alternative tools or state when not to use it, but the negative constraints ('Does not freeze the scene or measure packaged gameplay FPS') help an agent avoid misuse. It could be improved by explicitly referencing sibling tools like unreal_performance_compare or unreal_performance_job.

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