Agentvet

agentvet-mcp

MCP server for [`@mukundakatta/agentvet`](https://www.npmjs.com/package/@mukundakatta/agentvet). Lets Claude Desktop, Cursor, Cline, Windsurf, Zed, or any other MCP client validate LLM-generated tool-call args before execution and produce LLM-friendly retry messages when something's wrong.

npx -y @mukundakatta/agentvet-mcp

Three tools:

• `validate_tool_args` — check args against a small shape spec; returns { valid, error?, retry_hint? } where retry_hint is a ready-to-send LLM feedback message.
• `lint_tool_definition` — sanity-check a tool definition for common mistakes that hurt LLM tool-use accuracy.
• `generate_retry_message` — given a validation error, build the canonical LLM-facing retry message using agentvet's ToolArgError.toLLMFeedback() formatting.

Add to your client

Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{

"mcpServers": { "agentvet": { "command": "npx", "args": ["-y", "@mukundakatta/agentvet-mcp"] } } }

Same shape for Cursor (~/.cursor/mcp.json), Cline, Windsurf, Zed.

Tool examples

`validate_tool_args`:

{

"tool_name": "send_email", "args": { "to": "a@b.com" }, "shape": { "to": "string", "subject": "string", "body": "string" } }

Returns:

{

"valid": false, "error": "missing required field: subject", "retry_hint": "send_email rejected your args: missing required field: subject. Please call again with the corrected arguments." }

`lint_tool_definition`:

{

"tool": { "name": "BadName", "inputSchema": { "type": "object", "properties": { "x": { "type": "string" } } } } }

Returns warnings about non-snake_case name, missing description, missing field descriptions, and no required fields.

`generate_retry_message`:

{

"tool_name": "send_email", "validation_error": "missing required field: subject", "attempted_args": { "to": "a@b.com" } }

Returns the canonical retry feedback string the runtime callers see — so you can prepare retry text outside the live agent loop.

Why a separate MCP server

@mukundakatta/agentvet is a zero-dependency JavaScript library. This MCP server makes its validation primitives accessible from any MCP-aware AI assistant. Useful for quickly auditing a registry of tools, or asking the assistant "is this args object valid for my send_email tool?" without leaving the chat.

For runtime arg validation in your agent loop, use @mukundakatta/agentvet directly inside your Node process (it wraps your tool fn and throws ToolArgError synchronously).

Sibling MCP servers

Part of the agent-stack series:

• @mukundakatta/agentfit-mcp — *Fit it.*
• @mukundakatta/agentguard-mcp — *Sandbox it.*
• @mukundakatta/agentsnap-mcp — *Test it.*
• @mukundakatta/agentvet-mcp — *Vet it.* (this)
• @mukundakatta/agentcast-mcp — *Validate it.*

License

MIT