Playwright MCP (Model Context Protocol) arguments provide fine-grained control over browser automation behavior when integrating AI-assisted testing capabilities. These command-line arguments configure how the Playwright MCP server operates, defining everything from browser selection and capabilities to timeout management and output handling.
The primary purposes of these arguments are:
Environment Configuration: Define which browsers, devices, and capabilities are available for test execution
Behavior Control: Manage timeouts, session persistence, and trace recording for debugging
Output Management: Control logging levels and specify where artifacts (traces, screenshots, PDFs) are stored
AI Agent Optimization: Enable specific capabilities that AI agents can leverage for intelligent test generation and execution
By properly configuring these arguments in your MCP configuration file, you create a robust foundation for AI-driven test automation that balances flexibility, debugging capability, and performance.
1. --caps (Capabilities)
Syntax: --caps=testing,vision,pdf
Description: Defines the functional capabilities available to the Playwright MCP server. This controls what types of operations the AI agent can perform.
Available Options:
testing - Core browser automation and testing operations
vision - Screenshot capture and visual verification
pdf - PDF generation from web pages
Best Practice: Always include testing and vision for comprehensive web automation. Add pdf when document generation or archival is required.
Example Use Case: Testing a reporting dashboard that generates PDF exports requires --caps=testing,vision,pdf.
2. --browser (Browser Selection)
Syntax: --browser=chromium,webkit,firefox,chrome,edge
Description: Specifies which browser engines the MCP server can utilize for test execution. Supports multiple browsers for cross-browser testing.
Available Options:
chromium - Open-source Chromium browser (fastest, recommended for development)
firefox - Mozilla Firefox
webkit - Safari's browser engine
chrome - Google Chrome (branded version)
edge - Microsoft Edge
Best Practice: Include chromium,firefox,webkit for comprehensive cross-browser coverage. Add chrome and edge for enterprise environments requiring branded browser testing.
Example Use Case: E-commerce sites must test payment flows across all major browsers to ensure compatibility.
3. --console-level (Logging Level)
Syntax: --console-level=info
Description: Controls the verbosity of console output from the MCP server, helping balance debugging information with log noise.
Available Options:
error - Only critical errors
warn - Warnings and errors
info - General information, warnings, and errors (recommended)
debug - Detailed debugging information
trace - Complete execution traces (maximum verbosity)
Best Practice: Use info for development and CI/CD pipelines. Switch to debug or trace only when troubleshooting specific issues.
Example Use Case: During initial test development, --console-level=debug helps understand why AI-generated selectors might be failing.
