Scroll the current browser viewport by a bounded pixel delta and map the resulting screen, with the scroll constrained to the expected mapped screen.
Scroll the current browser viewport by a bounded pixel delta and map the resulting screen. The scroll acts only on the viewport of the expected mapped screen.
| Name | Required | Description | Default |
|---|---|---|---|
| dx | No | ||
| dy | No | ||
| port | No | ||
| app_id | No | ||
| target_url | No | ||
| expected_screen | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations the description carries the full burden, and it does disclose two real traits: the delta is 'bounded' and scrolling is scoped to the expected mapped screen. It omits error behavior on screen mismatch, what happens when scrolling past the viewport edge, and the side effect implied by 'map the resulting screen'.
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 action front-loaded and the scoping constraint second; no filler. The wording is slightly cryptic ('expected mapped screen') but structurally efficient.
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 6-parameter tool with no annotations, no output schema, and zero schema descriptions, the description leaves most parameters and all failure/return behavior unexplained. An agent could not reliably construct a correct call from it alone.
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%, so the description must carry parameter meaning, but it only gestures at dx/dy ('pixel delta') and expected_screen. Three parameters (port, app_id, target_url) are completely undocumented in both schema and description.
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 (scroll) and resource (browser viewport) plus the secondary effect (map the resulting screen). It is distinguishable from click/fill/observe siblings by action, though it never contrasts itself with them explicitly.
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?
No indication of when to choose scrolling over pulse_browser_observe or pulse_map_get, nor any when-not guidance. The only usage signal is the implicit precondition that a screen must already be mapped, which is never spelled out.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.