Scroll the inspected browser tab vertically by y pixels to navigate content; negative values scroll up. Use with tab, frame, and snapshot IDs to target the correct page context.
Scroll the inspected tab by y pixels (negative scrolls up).
| Name | Required | Description | Default |
|---|---|---|---|
| y | No | ||
| tabId | No | Chrome tab id (default: active tab) | |
| frameId | No | Frame id, default 0 | |
| snapshotId | No | snapshotId returned by chrome_snapshot; rejects stale actions |
Changes observed during successful MCP inspections.
v1.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, destructiveHint=true, idempotentHint=false, and openWorldHint=true, so the safety and mutability profile is known without the description. The description adds the meaning of negative y values, which is useful behavioral detail, but does not explain what makes scrolling destructive, whether a snapshot is required, or how stale actions are handled beyond what the schema already says.
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 that contains no redundant or filler language. It is sized appropriately for a simple scroll action.
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 four-parameter scroll tool with no output schema, the description is minimally adequate: it covers the core action and y semantics. It still omits usage routing against browser_scroll and does not discuss the snapshotId stale-action behavior that the schema mentions, which would be helpful context for safe invocation.
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 75%, and the undocumented parameter is y. The description compensates by defining y as pixel distance and explaining that negative values scroll upward, which is exactly the missing semantics. The other three parameters are covered by their schema descriptions.
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?
The description states a specific verb (Scroll) and resource (the inspected tab), and specifies the unit and direction semantics ('by y pixels', 'negative scrolls up'). However, it does not distinguish this Chrome-specific tool from the sibling browser_scroll, leaving an agent to infer the platform split.
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?
There is no when-to-use guidance, no prerequisites, and no mention of alternatives such as browser_scroll or when scrolling may be unnecessary. The direction note implies basic operation but not selection criteria.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.