playwright
Runs Playwright tests with JSON reporter and returns structured results with pass/fail status, duration, and error messages.
This record as markdown: /tools/io-github-dave-london-cargo/playwright.md
What playwright does on Cargo
AI agents invoke playwright to trigger actions in Cargo. 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.
Why playwright is rated High
Playwright tests run browser automation which can interact with external systems, web applications, and services. The tool executes arbitrary test code, which may have side effects depending on the tests (form submissions, state changes, etc.). This is clearly an Execute category action with high severity due to the broad blast radius of browser automation.
From the tool's definition 'Runs Playwright tests' — executes browser automation test suites against potentially live systems
Attacks that exploit this kind of access
The rule that runs playwright safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Cargo, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For playwright, this is the rule to start with:
playwright 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Cargo, apply this rule, and every playwright call is checked against it from then on.
Questions about playwright
Runs Playwright tests with JSON reporter and returns structured results with pass/fail status, duration, and error messages. It is categorised as a Execute tool in the Cargo MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Cargo MCP server in PolicyLayer and add a rule for playwright: 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 Cargo. Nothing to install.
playwright 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 playwright 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 playwright. 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.
playwright is provided by the Cargo MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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