Capture a JPEG image of the full page or a specific element to inspect visual content such as canvas or graphics that text snapshots cannot represent.
ÚLTIMO RECURSO (gasta tokens): imagen JPEG de la página o de un ref, para contenido puramente visual (canvas, gráficos, captchas no).
| Name | Required | Description | Default |
|---|---|---|---|
| ref | No | Ref de un elemento devuelto por browser_snapshot/browser_find (ej. 12 o "f1:7" en iframes) | |
| quality | No | ||
| fullPage | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description must carry behavioral weight. It does disclose the token cost and the output format (JPEG), which are genuinely useful. It does not state what quality defaults apply, whether the image is returned inline/base64 vs a path, or how it interacts with the current viewport versus full page — gaps that matter for a capture tool.
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 the cost warning first, then the capability, then the qualifying content type. Compact and appropriately sized, though the garbled 'captchas no' fragment costs some clarity.
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 3-parameter, zero-annotation, no-output-schema tool, the description covers the 'when' reasonably but leaves the return shape (inline data vs URL), default quality, and fullPage semantics to inference. Adequate to call it, insufficient to call it optimally.
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 only 33%, so the description should compensate, but it only restates that a screenshot can target 'la página o un ref'. The quality and fullPage parameters receive no explanation anywhere, leaving their defaults and effect (e.g., full document vs viewport) undocumented.
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 concrete verb+resource: produces a JPEG image of the page or of a given ref, and names the target use case (purely visual content such as canvas or graphics). It implicitly distinguishes itself from browser_snapshot (which yields structure, not pixels) via 'de la página o de un ref'. The trailing 'captchas no' is ambiguous about an edge case but does not obscure the core purpose.
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?
'ÚLTIMO RECURSO (gasta tokens)' explicitly tells the agent to try other tools first and warns about cost, and 'para contenido puramente visual (canvas, gráficos...)' bounds the qualifying cases. It stops short of naming the preferred alternative (browser_snapshot/browser_extract) or excluding specific scenarios cleanly, since 'captchas no' reads as a truncated caveat.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.