Compare the current AX tree against the snapshot taken before the last write/navigate action (click, type, submit, select, navigate, open, back, forward, scroll). Shows added, removed, and changed elements. Use after a click or form submission to see exactly what changed on the page instead of re...
Part of the DOMShell server.
Free to start. No card required.
AI agents use domshell_diff to create or modify resources in DOMShell. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call domshell_diff repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach DOMShell.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"domshell_diff": {
"limits": [
{
"counter": "domshell_diff_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full DOMShell policy for all 38 tools.
These attack patterns abuse exactly the kind of access domshell_diff gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Compare the current AX tree against the snapshot taken before the last write/navigate action (click, type, submit, select, navigate, open, back, forward, scroll). Shows added, removed, and changed elements. Use after a click or form submission to see exactly what changed on the page instead of re-exploring with ls/find.. It is categorised as a Write tool in the DOMShell MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the DOMShell MCP server in PolicyLayer and add a rule for domshell_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 DOMShell. Nothing to install.
domshell_diff is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the domshell_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 domshell_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.
domshell_diff is provided by the DOMShell MCP server (@apireno/domshell). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 38 DOMShell tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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