Get a diff scoped to a CSS selector region. Optionally diff from a bookmark.
AI agents call sdk_scoped_diff to retrieve information from UI Bridge MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and compares visual or structural differences in a UI region bounded by a CSS selector, optionally against a previously bookmarked state. It has no side effects—it does not modify, delete, or execute actions on the UI or data. It is a pure query/read operation for inspecting UI changes.
From the tool's definition Tool description states 'Get a diff scoped to a CSS selector region' — 'get' is a retrieval operation that compares UI states without modifying them. The reference to bookmarking suggests reading stored states for comparison purposes.
Attacks that exploit this kind of access
Get a diff scoped to a CSS selector region. Optionally diff from a bookmark. It is categorised as a Read tool in the UI Bridge MCP MCP Server, which means it retrieves data without modifying state.
Register the UI Bridge MCP server in PolicyLayer and add a rule for sdk_scoped_diff: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches UI Bridge MCP. Nothing to install.
sdk_scoped_diff is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the sdk_scoped_diff rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for sdk_scoped_diff. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
sdk_scoped_diff is provided by the UI Bridge MCP server (qontinui/ui-bridge-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
Teams ship this data inside their own products. See what a licence covers →