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MCP server for executing code in an interactive WebContainer sandbox environment with live preview capability
This MCP server exhibits severe definition quality deficiencies across all rubric dimensions. The single tool 'execute_in_sandbox' has a problematic name, minimal description, and critically incomplete parameter documentation. The source code shows only a mock implementation with hardcoded return values and no actual MCP server registration, transport layer, or protocol compliance. Tool definitions appear inferred rather than explicitly registered via MCP mechanisms.
Execute code files in an interactive WebContainer sandbox environment with live preview
Tool name 'execute_in_sandbox' lacks action verb prefix. Naming conventions recommend 'run_code_in_sandbox' or 'deploy_code_in_sandbox' to clearly signal the action to LLMs. Current name is ambiguous about whether execution or configuration occurs.
Tool description is only 109 characters and lacks critical context. Missing: when to use this tool, prerequisites, expected outcomes, error scenarios, and cost/latency implications. LLMs cannot reliably select this tool with such sparse documentation. Baseline tool descriptions average 194 chars with clear WHAT/WHEN/WHY.
Parameter 'code_files_map' lacks description entirely. The description field is missing. LLMs cannot infer what format files should be in, whether they are required, or what happens if the map is empty. Baseline: 100% of A+ tools have descriptions for ALL parameters.
| Scored | Grade | Overall | Spec posture | Rubric |
|---|---|---|---|---|
| 2026-09-23 | F | 21 | 2026-07-28+ | v2 |
Parameter 'framework' description is only 51 characters and provides no enum constraint. LLMs cannot determine valid values. Must be: 'The JavaScript framework for the sandbox environment. Must be one of: React-TypeScript, Vue3, Svelte, Plain-HTML, Next.js, Vite-React. Default: React-TypeScript.'
Input schema uses generic 'object' type with no property-level schema. The 'code_files_map' parameter declaration lacks type information on values (should be 'string') and no minProperties/maxProperties constraints. Schema is unstructured and cannot be validated.
Output schema is completely undocumented. Response returns {live_preview_url, console_logs, build_duration_ms} but LLMs have no specification of types, field meanings, or when fields may be absent. Baseline: 100% of A+ tools document return types.
No error handling or recovery guidance. Tool provides no information on failure modes (invalid code syntax, WebContainer unavailable, framework unsupported, timeout). LLMs receive no actionable recovery instructions.
Tool returned marked as WRITE risk but no security or permission documentation. Missing: required permissions, audit logging requirements, rate limits, and whether this tool supports dry-run or confirmation steps before execution.
No MCP server implementation visible in source. Provided code is a mock client class only (InteractiveCodeSandboxWebcontainerRunnerClient with hardcoded returns). No MCP server registration, no transport layer, no stdio or HTTP handler, no Tool registration via Protocol methods.