stop_trace

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

No annotations exist, so the description carries the full transparency burden. It discloses that traces auto-stop with max_calls/max_seconds limits and clean up, and that this tool is for early cancellation. It also states it's safe to call with no trace running, implying no error or side effect. However, it doesn't explain what happens to trace data (e.g., partial results) or return value, but given the tool's simplicity, it provides sufficient behavioral context.

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 long and front-loaded with the action. The second sentence provides context on normal behavior (auto-stop), and the third covers the edge case of no running trace. Every sentence adds value with no fluff or repetition.

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 is simple: 0 params, no output schema, no annotations. The description covers the purpose, when to use it, the lifecycle context, and safety. It is reasonably complete for the tool's complexity. It might be improved by mentioning what the call returns or any side effects on trace data, but for a simple stop operation, the description provides enough context to use it correctly.

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 has 0 parameters, and the schema coverage is 100% (effectively nothing to cover). Per the rubric, 0 params results in a baseline score of 4. The description adds context about the trace lifecycle but no parameter details are needed. This 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?

The description immediately states the tool's action: 'Abort a running trace early.' This is a specific verb+resource and clearly distinguishes stop_trace from its sibling trace_calls, which presumably starts traces. It also clarifies the trace lifecycle, making the purpose obvious.

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 explicitly explains when NOT to use the tool ('You do not normally need to call this') and when it IS useful ('if you want to cancel a trace before it finishes on its own'). It also notes that traces auto-stop and clean up, providing clear guidance for typical scenarios. Additionally, it mentions that it's safe to call even when no trace is running, which is helpful behavior guidance.

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