Capture an accessibility snapshot of the current page to get element references for interaction; pass a ref to return only that subtree.
Capture accessibility snapshot of the current page. Use this for getting references to elements to interact with. Pass a ref to see only that part of the page.
| Name | Required | Description | Default |
|---|---|---|---|
| ref | No | Only return the subtree of this element |
Changes observed during successful MCP inspections.
v0.4.0Input schema / properties / refAdded value: +{
+ "description": "Only return the subtree of this element",
+ "minLength": 1,
+ "type": "string"
+}v0.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful behavioral context: the tool's role as the producer of element refs that other tools consume, and the scoping effect of passing a ref.
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?
Three short sentences, zero filler, with the primary purpose front-loaded and the parameter guidance last. Every sentence 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 single-parameter read tool with no output schema, the description adequately covers purpose, usage, and the ref-scoping behavior. It could be slightly more complete by noting the ref format/prefix convention, but nothing critical 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?
Schema coverage is 100% and the ref property already documents "Only return the subtree of this element"; the description's "Pass a ref to see only that part of the page" largely restates it. Baseline 3 is appropriate when the schema carries the parameter documentation.
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 and resource ("Capture accessibility snapshot of the current page") and uses vocabulary that distinguishes it from the screenshot sibling. It does not explicitly name browser_screenshot to rule it out, so it stops short of a 5.
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?
"Use this for getting references to elements to interact with" gives concrete when-to-use context that links it to the click/type/hover siblings. There is no explicit when-not or named alternative, but the context is clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.