Vending Machine MCP Server

13 specialist AI agents for your coding assistant. Use them from Claude Code, Codex, or any MCP-compatible client.

Scope

This document describes the **vending-machine-mcp** PyPI package: a standalone stdio MCP server. It ships complete and does not depend on any other repository layout.

Source of truth for tools and agents in this package:

• vending_machine_mcp/mcp_server.py

Tools (Current Signatures)

Async Behavior

• hire_agent, run, and audit_code return a job_id.
• Use check_job(job_id) to retrieve final output.

Agents (Current Registry)

Quick Start

pip install vending-machine-mcp

Claude Code / Codex / Any MCP Client

{
  "mcpServers": {
    "vending-machine": {
      "command": "vending-machine-mcp"
    }
  }
}

Usage

> hire_agent("bug-hunter", "Review this auth middleware for vulnerabilities: <paste code>")
> check_job("abc123")
> run("S-7K2M", "input payload")
> audit_code("<paste code>")
> vector_store_add("my-kb", "Full note text...", metadata_json='{"source":"notes.md"}')
> vector_store_search("my-kb", "How do we deploy?")
> query_knowledge("my-kb", "Summarize the deployment process")

Embed and query flow (embeddings-agent + query_knowledge)

> hire_agent("embeddings-agent", "Embed my API docs: <paste text>")
> check_job("job-id")
  -> "Stored 24 chunks in collection `embeddings-api-docs-txt`.
      Query with: query_knowledge(collection='embeddings-api-docs-txt', question='...')"
> query_knowledge("embeddings-api-docs-txt", "How does authentication work?")
  -> "Based on the documents: Authentication uses JWT tokens issued by... [1] [3]"

What works out of the box

After pip install and pointing your MCP client at vending-machine-mcp, you do not need a separate database or vector service. Several tools are useful with no API keys at all:

• **list_agents** — lists agents (starting a run still needs OpenRouter; see Requirements).
• **search_scripts** — natural-language search over bundled marketplace scripts using a local SQLite index and deterministic local embeddings when no embedding provider key is set. Results are real and ranked; quality is better if you set **VOYAGE_API_KEY** (or OpenAI / Gemini — same priority as below).
• **info** — script details from the in-memory store; similar scripts / chain hints use the same SQLite index when available.
• **vector_store_add / vector_store_search / vector_store_list** — personal collections in another local SQLite file; same local hash fallback without keys.
• **query_knowledge** — RAG over any collection: retrieves context chunks then asks an LLM to answer. Requires at least one LLM key (**OPENROUTER_API_KEY, **OPENAI_API_KEY, or **GEMINI_API_KEY**) for the answer step; embedding search itself works with local hash when no embedding key is set.

Anything that calls models (hire_agent, check_job results, audit_code) needs **OPENROUTER_API_KEY. Anything that runs code (run, run_code, sandbox paths inside agents) needs a sandbox key (DAYTONA_API_KEY or E2B_API_KEY). The **embeddings-agent expects at least one embedding provider key (see Requirements). No extra setup steps beyond env vars and MCP config.

Marketplace script search (search_scripts)

• Implemented in vending_machine_mcp/graph.py: a SQLite script index with semantic search over embedded script text. No external graph or vector database service is required.
• Default DB: ~/.local/share/vending-machine-mcp/script_index.sqlite3 (or $XDG_DATA_HOME/vending-machine-mcp/…). Override with **SCRIPT_INDEX_DB_PATH**.
• Embeddings for indexing and queries use Voyage voyage-code-3 (document/query types) when **VOYAGE_API_KEY** is set; otherwise OpenAI → Gemini → deterministic local hash, same idea as the vector store. Only rows whose stored vector length matches the query embedding are ranked (avoid mixing providers without re-seeding or clearing the DB).

Local vector store

• Default DB path: ~/.local/share/vending-machine-mcp/vector_store.sqlite3 (or $XDG_DATA_HOME/vending-machine-mcp/…). Override with **VECTOR_STORE_DB**.
• Uses the same embedding key priority as vector_store_add: Voyage → OpenAI → Gemini → deterministic local hash. Override with **EMBEDDING_PROVIDER** / **EMBEDDING_MODEL** / **EMBEDDING_DIMENSIONS** env vars, or pass provider/model/dimensions directly to each tool call.
• The provider and model used are stored per-document. When searching or querying, the tool auto-detects which provider/model the collection uses and embeds the query the same way.

OPENAI_API_KEY: what it does (and what it does not)

OPENAI_API_KEY is for OpenAI’s Embeddings API (text-embedding-3-small) wherever the package needs vectors. It is not a substitute for **OPENROUTER_API_KEY, which is what runs the LLM inside agents (including **embeddings-agent).

With **OPENAI_API_KEY** set (and no **VOYAGE_API_KEY**, which takes priority):

• **search_scripts** — better semantic search over the marketplace script index (same key used when seeding/indexing scripts).
• **vector_store_add / vector_store_search** — embeddings for your personal collections (plus **vector_store_list** to inspect them).

There is no MCP tool that runs raw SQL. Your chat app talks to the two local SQLite files only through tools: use **search_scripts** for bundled scripts, and **vector_store_search** / **query_knowledge** / **vector_store_list** for data you added with **vector_store_add** or the **embeddings-agent**.

**embeddings-agent**: call **hire_agent("embeddings-agent", …)** then **check_job**. The agent now persists all chunks + vectors into the vector store under a named collection. Use **query_knowledge(collection, question)** afterward to ask questions about that data. The agent graph needs **OPENROUTER_API_KEY; the embedding steps need at least one embedding key (**OPENAI_API_KEY / Voyage / Gemini); **query_knowledge** needs at least one LLM key (OpenRouter, OpenAI, or Gemini) for the answer step.

Requirements

• Python 3.11+
• **OPENROUTER_API_KEY** — required to run agents (hire_agent, audit_code, and any tool that executes an LLM workflow). Not required only to list agents or to use search / vector store without agents.
• Sandbox — required for **run, **run_code, and code execution inside agents: set **DAYTONA_API_KEY** or **E2B_API_KEY**. The server picks a provider when both exist; set **SANDBOX_PROVIDER=daytona** or **SANDBOX_PROVIDER=e2b** to force one.
• **embeddings-agent** — same as other agents: **OPENROUTER_API_KEY** is required to run it via **hire_agent. For embedding operations inside that agent, use at least one of **OPENAI_API_KEY, **VOYAGE_API_KEY**, or **GEMINI_API_KEY** (**GOOGLE_API_KEY** is an alias for Gemini).

Optional for better (not required for working) semantic search and vector store without using **embeddings-agent**: the same embedding keys. Priority is Voyage → OpenAI → Gemini → local hash (see sections above).

Environment variables can be set in the shell that launches the MCP server or in a **.env** file in the server’s working directory (the package loads it on startup).