Redeem an output handle returned by a large-output tool (read_page, crawl,
AI agents call oc_output_fetch to retrieve information from OpenChrome without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool fetches stored output from other tools rather than executing new operations or modifying state. It is purely retrieving and reading data, making it a Read category tool. The low severity reflects that fetching output data poses minimal risk compared to execution or destructive operations.
From the tool's definition Tool name 'oc_output_fetch' and description 'Redeem an output handle returned by a large-output tool (read_page, crawl...)' indicates retrieval of previously computed results.
Documented attack patterns abuse exactly the kind of access oc_output_fetch gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and OpenChrome, and nothing reaches the server without passing your rules. This is the rule we recommend for oc_output_fetch:
{
"version": "1",
"default": "deny",
"tools": {
"oc_output_fetch": {}
}
}oc_output_fetch is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Redeem an output handle returned by a large-output tool (read_page, crawl,. It is categorised as a Read tool in the OpenChrome MCP Server, which means it retrieves data without modifying state.
Register the OpenChrome MCP server in PolicyLayer and add a rule for oc_output_fetch: 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 OpenChrome. Nothing to install.
oc_output_fetch 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 oc_output_fetch 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 oc_output_fetch. 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.
oc_output_fetch is provided by the OpenChrome MCP server (shaun0927/openchrome). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 106 OpenChrome tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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106 OpenChrome tools catalogued and risk-classified — across an index of 42,500+ MCP servers.