Capture a screenshot of a visible element in an IE-mode page using a fresh reference. Scrolling may occur and existing references are invalidated; driver support is required.
Capture a visible element using a fresh reference. May scroll and expose page information; invalidates refs. No fallback if the driver does not support element screenshots.
| Name | Required | Description | Default |
|---|---|---|---|
| ref | Yes |
Changes observed during successful MCP inspections.
v0.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden well: it discloses that it may scroll (side effect), exposes page information, and importantly invalidates refs — a critical behavioral warning. It omits return format, but the side-effect disclosure is strong.
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 tight sentences with the core verb and constraints front-loaded. Every clause carries meaning (freshness requirement, side effects, driver limitation).
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?
No annotations or output schema, and the description covers the main behavioral concerns (scrolling, ref invalidation, driver support). It could be more complete by explaining what the ref is and that the result is image data, but covers the essentials.
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 coverage is 0% for the single 'ref' parameter, so the description must compensate. 'Using a fresh reference' adds a freshness hint, but doesn't explain that ref is a reference token from a prior snapshot or point to browser_snapshot for obtaining one.
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 (visible element) with the key constraint 'using a fresh reference', distinguishing it from the page-level browser_screenshot. However, it never explicitly names browser_screenshot or browser_inspect_element as the alternatives, so the differentiation is implicit.
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 only implied — 'using a fresh reference' hints at the prerequisite and 'No fallback if the driver does not support element screenshots' flags a limitation. It lacks explicit when-to-use guidance versus sibling screenshot/inspect tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.