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Semantic router for MCP ecosystems - Discover, manage, and execute tools across multiple MCP servers with progressive disclosure
semantic-mcp provides 15 tools with mostly complete schemas and descriptions, but exhibits significant gaps in parameter documentation, error handling guidance, and output schema clarity. Tool names follow verb_noun convention well (search_tools, get_server_info, execute_tool). Descriptions average ~150 chars and explain purpose, but many lack actionable next-step guidance. Critical issue: parameters like 'arguments' (object type) lack detailed schema documentation; 'operation' enum in semantic_router is massive (13 values) without clear disambiguation. Error handling is minimal, most tools return generic exception messages rather than recovery guidance. Output schemas are not formally documented; responses are JSON-serialized text blocks rather than structured ToolResult fields. Progressive disclosure pattern mentioned in semantic_router description is not consistently applied across tools.
Cancel a running background task.
Execute a tool on a running MCP server with specified arguments. Supports both synchronous and asynchronous (background) execution with timeout and priority control.
Retrieve offloaded content (text, images, audio) that was stored due to size constraints. Supports chunked retrieval for large text content.
Get detailed information about a specific MCP server including title, summary, capabilities, limitations, and tool count.
List all tools available on a specific MCP server with pagination support. Returns lightweight results with name, serverName, description, and title.
Get overall statistics about the MCP ecosystem including total number of servers and tools indexed.
semantic_router tool combines 13 distinct operations (search_tools, execute_tool, manage_server, etc.) into a single mega-tool with massive enum. This violates single-responsibility principle and forces LLMs to reason about which operation to select rather than calling the appropriate tool directly.
'arguments' parameter in execute_tool is typed as object with no schema constraints. LLMs cannot validate argument structure before execution. Should document expected schema or require get_tool_details call first.
Error handling returns generic exception messages ('Execution failed: {str(e)}') with no recovery guidance. Should categorize errors (retryable, user-fixable, fatal) and suggest next steps like 'Server not running, call manage_server(server_name, start) first'.
Inferred effective spec: <=2025-11-25.
| Scored | Grade | Overall | Spec posture | Rubric |
|---|---|---|---|---|
| 2026-09-23 | D | 59 | <=2025-11-25 | v2 |
Get full schema and details for a specific tool including input schema, description, and server information. Required before tool execution.
List all currently running MCP servers.
List all indexed MCP servers with pagination support. Returns lightweight results with name, title, and tool count.
List all background tasks with their current status.
Start or shutdown an MCP server. Required before executing tools on a server.
Poll the status and result of a background task. Returns status ('running', 'completed', 'failed', 'not_found') and result when available.
Search for MCP servers using natural language semantic search. Returns lightweight results with name, title, tool count, and relevance score.
Search for tools across MCP servers using natural language semantic search. Returns lightweight results with name, serverName, description, title, and relevance score.
Universal gateway to the MCP Runtime ecosystem. Execute any MCP operation through a single unified interface. DESIGN: Progressive disclosure - lightweight metadata first (~30-40 tokens/item), full details only when needed. This prevents context bloat when orchestrating across many servers/tools.
Output schemas not formally documented. Tools return ToolResult with TextContent blocks (JSON-serialized strings) rather than structured fields. LLMs cannot reliably extract data for chaining (e.g., task_id from execute_tool response).
No pagination limit enforcement documented. list_servers and get_server_tools accept limit up to 50, but no guidance on default behavior or maximum safe values. Should cap at 20-50 and document in descriptions.