screenshotCapture the active tab as an image to confirm the page looks correct during a demo recording. Use it for visual checks before moving on.
Capture what the recorded tab shows right now, as an image, to check the page looks right. The tab must be the active tab of its window.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare readOnlyHint and openWorldHint, so the safety profile is already covered. The description adds a real operational precondition not present in the annotations: the tab must be the active tab of its window, plus the 'right now' timing semantics that imply a live capture. It does not describe return format, but no output schema is needed for an image.
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 short sentences, no filler, with the core action and its purpose front-loaded and the precondition placed second. Every clause 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?
For a zero-parameter read tool with annotations covering safety and no output schema, the description supplies purpose plus the one precondition an agent must satisfy. It stops short of relating itself to the surrounding flow (navigate, wait_for, snapshot), but nothing critical to invoking it 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, which is the baseline-4 case. There is nothing parameter-wise the description needs to compensate for, and it correctly avoids inventing 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 (capture) and resource (what the recorded tab shows now) plus the output form (as an image), so the agent knows this returns a picture rather than data. It does not explicitly differentiate itself from the similarly named sibling 'snapshot' or 'probe_capture', leaving a small ambiguity about which one produces an image.
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?
'to check the page looks right' implies a verification use case, which is decent context. However, it never tells the agent when to prefer this over siblings like snapshot or probe_capture, nor when not to use it.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.