Stop the active performance trace recording on the target webpage.
Stop the active performance trace recording on the target webpage.
| Name | Required | Description | Default |
|---|---|---|---|
| pageId | Yes | Targets a specific page by ID. | |
| filePath | No | The absolute file path, or a file path relative to the current working directory, to save the raw trace data. For example, trace.json.gz (compressed) or trace.json (uncompressed). |
Changes observed during successful MCP inspections.
v0.1.1Input schema / additionalPropertiesPrevious value: -{}New value: +falsev0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Only readOnlyHint=false is given, so the description carries the burden of explaining the mutation, yet it says nothing about what happens to captured data when filePath is omitted (discarded? returned?), how existing trace data is affected, or the error behavior with no active trace. These are exactly the details an agent needs before invoking a stop operation.
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?
A single front-loaded sentence with zero filler, but its brevity is also what leaves the behavioral gaps unaddressed; efficiency is good, completeness is the tradeoff.
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 simple two-parameter tool with full schema coverage and no output schema, the definition is minimally sufficient, but an agent still cannot tell whether the trace result is saved, returned, or lost unless filePath is supplied.
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 100%, and the filePath schema entry already explains absolute/relative paths and compressed vs uncompressed formats. The description adds no parameter meaning of its own, so the baseline 3 applies.
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 ('Stop') and resource ('active performance trace recording') with a clear scope ('target webpage'). It implicitly contrasts with the sibling performance_start_trace, though it never names it or another alternative explicitly.
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 word 'active' implies a trace must already be running, but the description never says to call performance_start_trace first, nor what happens if no trace is active. Usage is implied rather than stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.