Quick feasibility check before automating a platform. Scans the page for known blockers (captchas, WebGL, iframes), checks against playbook errors, tests selector availability. Returns go/yellow/red.
AI agents call playbook_preflight to retrieve information from ScreenHand without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is a diagnostic/analysis tool that performs queries and validation checks to assess feasibility before automation runs. It retrieves information about page state and blocker detection but does not execute commands, modify data, delete anything, or move money. The read-only nature (scanning, checking, testing without modification) makes it firmly a Read operation with minimal risk.
From the tool's definition The tool 'scans the page', 'checks against playbook errors', and 'tests selector availability'—all passive inspection actions. It returns a status signal (go/yellow/red) with no side effects or state changes.
Documented attack patterns abuse exactly the kind of access playbook_preflight gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and ScreenHand, and nothing reaches the server without passing your rules. This is the rule we recommend for playbook_preflight:
{
"version": "1",
"default": "deny",
"tools": {
"playbook_preflight": {}
}
}playbook_preflight is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Quick feasibility check before automating a platform. Scans the page for known blockers (captchas, WebGL, iframes), checks against playbook errors, tests selector availability. Returns go/yellow/red. It is categorised as a Read tool in the ScreenHand MCP Server, which means it retrieves data without modifying state.
Register the ScreenHand MCP server in PolicyLayer and add a rule for playbook_preflight: 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 ScreenHand. Nothing to install.
playbook_preflight 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 playbook_preflight 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 playbook_preflight. 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.
playbook_preflight is provided by the ScreenHand MCP server (manushi4/screenhand). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from ScreenHand, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
89 ScreenHand tools catalogued and risk-classified — across an index of 43,000+ MCP servers.