Rubber Duck MCP Server

An MCP (Model Context Protocol) server that acts as a bridge to query multiple LLMs -- both OpenAI-compatible HTTP APIs and CLI coding agents. Just like rubber duck debugging, explain your problems to various AI "ducks" and get different perspectives!. Its 15 documented tools cover duck, ducks, mcp. It runs locally over stdio via the published package.

People connecting developer tools tools to Claude, Cursor, VS Code, or another MCP client. The project is written in TypeScript.

VERIFIED ACTIVE

LAST COMMIT 2026-08-19 · ★ 175 · #14 OF 139 MAINTAINED DEVELOPER TOOLS · VERIFIED 2026-08-25

MIT · TypeScript servers · how we verify → /methodology

01 · Install Rubber Duck

Claude Code

claude mcp add nesquikm-mcp-rubber-duck -- npx -y mcp-rubber-duck

Claude Desktop / Cursor / VS Code - add to config

{
  "mcpServers": {
    "nesquikm-mcp-rubber-duck": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-rubber-duck"
      ]
    }
  }
}

Same JSON for Cursor. For VS Code, rename the top-level key from `mcpServers` to `servers`.

Using another client? Same JSON, different key

Claude Desktop · mcpServers

Cursor · mcpServers

VS Code · servers

Windsurf · mcpServers

Zed · context_servers

Cline · mcpServers

Roo Code · mcpServers

Continue · mcpServers

LibreChat · mcpServers

Gemini CLI · mcpServers

Codex CLI · mcp_servers

Full setup guides: every client.

02 · Evidence

Security posture

What to check before giving this server access to your agent - from the registry, GitHub, and our own probes. We don't score safety; we show what's verifiable.

runs as local process (stdio) - runs on your machine with your user's permissions

license MIT - declared in the repository

npm package mcp-rubber-duck - unscoped; check the name against the project README before installing

registry namespace io.github.nesquikm is GitHub-verified and matches the repo owner

03 · What Rubber Duck can do

Prose above is summarized from the project's README and registry record - no invented capabilities.

What you can build

With this server connected, an agent can ask a single question to a specific LLM provider, list configured providers and health status, list available models for providers, and ask the same question to multiple providers simultaneously.

Capability map

Tools grouped from the project's README - what Rubber Duck lets an agent do.

Duck

5 tools - e.g. Get responses from all configured ducks; Multi-duck voting with reasoning and confidence; Have one duck evaluate and rank others' responses

duck_council · duck_vote · duck_judge · duck_iterate · duck_debate

read & search

4 tools - e.g. List configured providers and health status; List available models for providers; Usage statistics and estimated costs

list_ducks · list_models · get_usage_stats · get_pending_approvals

Ask

1 tool - e.g. Ask a single question to a specific LLM provider

ask_duck

Chat

1 tool - e.g. Conversation with context maintained across messages

chat_with_duck

Clear

1 tool - e.g. Clear all conversation history

clear_conversations

Compare

1 tool - e.g. Ask the same question to multiple providers simultaneously

compare_ducks

Mcp

1 tool - e.g. MCP Bridge status and connected servers

mcp_status

Approve

1 tool - e.g. Approve or deny a duck's MCP tool request

approve_mcp_request

Latest releases

v1.20.5 · 2026-08-19

1.20.5 (2026-08-19) · update LLM pricing data (2026-08-19)

v1.20.4 · 2026-08-14

1.20.4 (2026-08-14) · mcp-bridge: warn instead of silently ignoring a global trusted-tools "" (ddcb451), closes #129

v1.20.3 · 2026-08-10

1.20.3 (2026-08-10) · clear every override-reachable audit-ci advisory · scope audit-ci allowlist to the bundled-npm paths

04 · Who maintains Rubber Duck

rubber-duck is maintained by nesquikm. It's the only MCP server we track from this author; the repo dates to Aug 2025.

05 · Facts

repository: github.com/nesquikm/mcp-rubber-duck
category: developer tools - ranked #14 of 139 actively-maintained developer tools servers as of 2026-08-25.
release cadence: 10+ releases in the last 90 days (latest 2026-08-19)
registry: io.github.nesquikm/rubber-duck (active, first published 2025-09-17 · 4 versions)
packages: npm:mcp-rubber-duck

06 · Rubber Duck FAQ

Is Rubber Duck still maintained?

Yes - as of 2026-08-25, its last commit was 2026-08-19 and it shipped 10+ releases in the last 90 days. We re-verify nightly.

What can Rubber Duck do?

How do I install Rubber Duck?

Run `npx -y mcp-rubber-duck`. You can also paste the ready-made client config above.

Does Rubber Duck run locally?

Yes - it's a stdio server: it runs on your machine (via npx) with your user's permissions. Your data stays local unless the server itself calls external APIs.

07 · Alternatives to Rubber Duck

Alternatives to Rubber Duck

Maintained developer tools servers if Rubber Duck isn't the fit.

Pairs well with

Servers that cover what Rubber Duck doesn't - only shown when the pairing reason fits the companion.

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