Loading ToolBench
Model Context Protocol server for Playwright browser automation and API testing
The server provides 24 well-structured tools with explicit schemas and descriptions. Most tools have clear input schemas and reasonable descriptions (averaging ~80 chars), meeting baseline expectations. However, there are significant gaps: (1) descriptions are often generic and lack actionable guidance for when/why to use each tool, (2) several tools lack dependency hints or recovery guidance, (3) parameter descriptions are minimal and don't explain format constraints, (4) output schemas are not documented, responses are not shown in the tool definitions, and (5) error handling patterns are not evident from the code snippets provided. The naming is mostly good (verb_noun convention), but some tools like 'playwright_get_visible_text' and 'playwright_get_visible_html' lack clarity about what 'visible' means (is it text in viewport? rendered only?). Tools like 'playwright_get' and 'playwright_post' are generic HTTP verbs without context. The codegen tools (start_codegen_session, end_codegen_session, get_codegen_session, clear_codegen_session) form a cohesive set but descriptions lack detail on session lifecycle, file formats, or failure modes. Overall, this is a competent foundation that falls short of production-grade polish, descriptions would benefit from stronger context, output schemas should be documented, and error recovery guidance is absent.
Clear a code generation session without generating a test
End a code generation session and generate the test file
Get information about a code generation session
Click an element on the page
Close the browser and release all resources
Retrieve console logs from the browser with filtering options
Perform an HTTP DELETE request
HTTP API tools (playwright_get, playwright_post, playwright_put, playwright_patch, playwright_delete) use generic HTTP verb names without context. These are ambiguous and conflict with MCP resource semantics. LLMs cannot distinguish when to use these vs. dedicated domain tools.
Output schemas are not documented in tool definitions. The source code does not show what fields are returned by any tool. LLMs cannot plan downstream calls or extract needed data without knowing response structure. This violates pattern:tool and pattern:response-shaper.
Inferred effective spec: <=2025-11-25.
| Scored | Grade | Overall | Spec posture | Rubric |
|---|---|---|---|---|
| 2026-09-22 | C | 63 | <=2025-11-25 | v2 |
| 2026-03-09 | F | 41 | - | v1 |
Execute JavaScript in the browser console
fill out an input field
Perform an HTTP GET request
Get all visible HTML from the current page
Get all visible text from the current page
Hover an element on the page
Click an element in an iframe on the page
Fill an element in an iframe on the page
Navigate to a URL
Perform an HTTP PATCH request
Perform an HTTP POST request
Perform an HTTP PUT request
Resize the browser viewport using manual dimensions or device presets. Supports 143+ device presets including iPhone, iPad, Android devices, and desktop browsers with proper user-agent and touch emulation.
Take a screenshot of the current page or a specific element
Select an element on the page with Select tag
Upload a file to an input[type='file'] element on the page
Start a new code generation session to record Playwright actions
Parameter descriptions lack actionable detail. Example: 'playwright_click' description is 'Click an element on the page' (22 chars) with no guidance on when to use it, what happens on failure, or expected pre-conditions. Descriptions should be 50 - 200 chars and explain WHAT, WHEN, and recovery paths.
Codegen session tools lack lifecycle documentation. It is unclear: what format are generated tests? How are sessions stored? What happens if a session expires? How do you handle partial recordings? Descriptions should answer these upfront to prevent wasted agent calls.
No visible error handling or recovery guidance. Tools document no error codes, failure modes, or suggested next steps. Example: if playwright_navigate fails with timeout, what should the LLM do? Retry with longer timeout? Use a different browser? Current implementation provides no guidance.
'playwright_get_visible_text' and 'playwright_get_visible_html' use the term 'visible' without definition. Does this mean text in the current viewport? All rendered text? Text not hidden by CSS? Ambiguity forces LLMs to guess and may lead to wrong tool selection.
Tools that accept file paths (playwright_upload_file, start_codegen_session with outputPath) lack path validation guidance. Should these accept relative paths? What happens if the directory doesn't exist? Are there sandbox restrictions? Parameter descriptions should clarify.