Capture a screenshot without bounding boxes and store it as a resource. Provide a resourceName to identify the screenshot. It
AI agents invoke save_unmarked_screenshot to trigger actions in Steel MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
This tool executes a browser-level action (capturing the current browser/page state as a screenshot) and persists the result as a named resource. It spans Execute (triggering a browser action) and Write (storing the resource), so Execute is chosen as the more severe category. Misuse could expose sensitive page content visible in the browser session.
From the tool's definition 'Capture a screenshot' and 'store it as a resource' — triggers a browser action (screenshot capture) and writes data to storage
Documented attack patterns abuse exactly the kind of access save_unmarked_screenshot gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Steel MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for save_unmarked_screenshot:
{
"version": "1",
"default": "deny",
"tools": {
"save_unmarked_screenshot": {
"limits": [
{
"counter": "save_unmarked_screenshot_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}save_unmarked_screenshot stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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Capture a screenshot without bounding boxes and store it as a resource. Provide a resourceName to identify the screenshot. It. It is categorised as a Execute tool in the Steel MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Steel MCP Server MCP server in PolicyLayer and add a rule for save_unmarked_screenshot: 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 Steel MCP Server. Nothing to install.
save_unmarked_screenshot is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the save_unmarked_screenshot 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 save_unmarked_screenshot. 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.
save_unmarked_screenshot is provided by the Steel MCP Server MCP server (steel-dev/steel-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 9 Steel MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
9 Steel MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.