ovos-persona-server

A single HTTP server that exposes one OVOS Persona as eight concurrent API surfaces — so any LLM client (OpenAI SDK, LangChain, Ollama tools, Anthropic SDK, Google Gemini SDK, Cohere SDK, HuggingFace TGI client, AWS Bedrock client, or any A2A agent) can talk to your OVOS persona without changes.

Table of Contents

• What is a Persona?
• Installation
• Quick Start
• API Surfaces
• A2A Endpoint
• Persona Config Examples
• Streaming
• Embeddings
• Authentication
• Troubleshooting

What is a Persona?

An OVOS Persona is a JSON file that chains together one or more solver plugins. Solvers are tried in order until one returns an answer. You can mix LLMs, knowledge bases, and fallback bots in a single persona — no GPU required for non-LLM setups.

{
  "name": "OldSchoolBot",
  "solvers": [
    "ovos-solver-wikipedia-plugin",
    "ovos-solver-ddg-plugin",
    "ovos-solver-plugin-wolfram-alpha",
    "ovos-solver-wordnet-plugin",
    "ovos-solver-rivescript-plugin",
    "ovos-solver-failure-plugin"
  ],
  "ovos-solver-plugin-wolfram-alpha": { "appid": "YOUR_API_KEY" }
}

Find solver plugins at github.com/OpenVoiceOS.

Installation

# Base server (no A2A)
pip install ovos-persona-server

# With A2A server support
pip install 'ovos-persona-server[a2a]'

With uv (recommended in OVOS workspaces):

uv pip install 'ovos-persona-server[a2a]'

Quick Start

# Start serving a persona on port 8337
ovos-persona-server --persona /path/to/my-persona.json

# Also expose it as an A2A agent
ovos-persona-server \
  --persona /path/to/my-persona.json \
  --a2a-base-url http://localhost:8337/a2a

The server binds to 0.0.0.0:8337 by default. Visit http://localhost:8337/docs for the interactive API reference (Swagger UI).

API Surfaces

Every API is served on a vendor-prefixed path so multiple clients can coexist without conflict.

Deprecated legacy paths

For backwards compatibility, /v1/... maps to /openai/v1/... and /api/... maps to /ollama/api/.... These paths send Deprecation and Link response headers and will be removed in a future major version. Migrate to the prefixed paths.

Quick test with curl

# OpenAI-compatible chat
curl -s http://localhost:8337/openai/v1/chat/completions \
  -H 'Content-Type: application/json' \
  -d '{"model":"","messages":[{"role":"user","content":"hello"}]}' \
  | python3 -m json.tool

# Ollama-compatible chat
curl -s http://localhost:8337/ollama/api/chat \
  -H 'Content-Type: application/json' \
  -d '{"model":"","messages":[{"role":"user","content":"hello"}]}'

A2A Endpoint

ovos-persona-server can expose your persona as a standard A2A agent server, enabling any A2A client to interact with it — including ovos-a2a-agent running on another OVOS instance.

Enable A2A

ovos-persona-server \
  --persona my-persona.json \
  --a2a-base-url http://myhost:8337/a2a

The --a2a-base-url flag:

• Activates the A2A endpoint at /a2a.
• Sets the url field in the Agent Card returned at GET /a2a/.well-known/agent.json.
• Must be the publicly reachable URL of the /a2a mount — this is what A2A clients use to discover the server.

Verify

# Fetch the Agent Card
curl http://localhost:8337/a2a/.well-known/agent.json | python3 -m json.tool

# Send a message
curl -X POST http://localhost:8337/a2a/ \
  -H 'Content-Type: application/json' \
  -d '{
    "jsonrpc": "2.0",
    "id": "1",
    "method": "message/send",
    "params": {
      "message": {
        "role": "user",
        "parts": [{"kind": "text", "text": "hello"}]
      }
    }
  }'

Connecting ovos-a2a-agent to this server

On another OVOS instance:

{
  "name": "remote-persona",
  "chat_module": "ovos-a2a-agent",
  "ovos-a2a-agent": {
    "url": "http://myhost:8337/a2a"
  }
}

A2A streaming

The A2A endpoint supports message/stream. Persona sentence chunks are emitted as TaskArtifactUpdateEvent SSE events. Enable streaming on the client side (e.g. "streaming": true in ovos-a2a-agent config).

A2A without a2a-sdk

If a2a-sdk is not installed and --a2a-base-url is provided, the server starts normally and logs a warning. All other API surfaces continue to work.

Persona Config Examples

LLM persona (OpenAI-compatible backend)

{
  "name": "gpt-persona",
  "chat_module": "ovos-openai-plugin",
  "ovos-openai-plugin": {
    "api_key": "sk-...",
    "model": "gpt-4o-mini"
  }
}

Knowledge-base + LLM fallback

{
  "name": "smart-assistant",
  "solvers": [
    "ovos-solver-wikipedia-plugin",
    "ovos-solver-ddg-plugin",
    "ovos-solver-wordnet-plugin",
    "ovos-openai-plugin",
    "ovos-solver-failure-plugin"
  ],
  "ovos-openai-plugin": {
    "api_key": "sk-...",
    "model": "gpt-4o-mini"
  }
}

Rivescript chatbot (no GPU, no API key)

{
  "name": "rivescript-bot",
  "solvers": [
    "ovos-solver-rivescript-plugin",
    "ovos-solver-failure-plugin"
  ]
}

Streaming

All seven non-A2A APIs support SSE streaming where the upstream spec defines it. Pass "stream": true (OpenAI / Cohere / TGI) or the equivalent for each API. See docs/streaming.md for per-API details.

OPM Tool Plugins — MCP and UTCP exposure

Installed ToolBox plugins (OPM entry-point group opm.agents.toolbox) are automatically surfaced over two protocols when the server starts.

Installing the MCP extra

pip install ovos-persona-server[mcp]

Without the [mcp] extra only the UTCP endpoints are active.

UTCP — Universal Tool Calling Protocol

Two endpoints are added at /tools:

Fetch the manual:

curl http://localhost:8337/tools/manual

Response shape:

{
  "utcp_version": "1.0",
  "tools": [
    {
      "name": "my_tool",
      "description": "Does something useful.",
      "tool_provider": {
        "type": "http",
        "method": "POST",
        "url": "http://localhost:8337/tools/my_tool",
        "content_type": "application/json"
      },
      "inputs": [
        {"name": "query", "type": "string", "required": true, "description": "Search query"}
      ],
      "output_schema": { ... }
    }
  ]
}

Invoke a tool:

curl -X POST http://localhost:8337/tools/my_tool \
     -H "Content-Type: application/json" \
     -d '{"query": "hello"}'

MCP — Model Context Protocol

When the [mcp] extra is installed, the server mounts an MCP SSE endpoint at /mcp. Each installed ToolBox tool is registered as an MCP tool with the name, description, and JSON Schema derived from its OPM definition.

Claude Desktop / MCP client config:

{
  "mcpServers": {
    "ovos-persona-tools": {
      "url": "http://localhost:8337/mcp/sse"
    }
  }
}

Standalone stdio MCP server (for clients that spawn a subprocess):

ovos-persona-tools-mcp

This runs the same tool set over the stdio MCP transport.

Writing a ToolBox plugin

Implement ToolBox from ovos_plugin_manager.templates.agent_tools and register it under the opm.agents.toolbox entry-point group:

# pyproject.toml
[project.entry-points."opm.agents.toolbox"]
my_toolbox = "my_package.toolbox:MyToolBox"

The server picks it up automatically on the next start.

Client side usage

The OpenAI and Ollama routers expose /embeddings endpoints. These require a solver plugin that implements get_embeddings(text). If no such solver is loaded the endpoint returns HTTP 501. See docs/embeddings.md.

Authentication

The server itself does not enforce authentication — deploy behind a reverse proxy (nginx, Caddy, Traefik) with TLS and auth if public exposure is required. For the A2A endpoint, A2A clients that require bearer tokens can be configured on the client side (api_key in ovos-a2a-agent config).

Troubleshooting

Failed to load persona (500 on startup) The persona JSON file was not found or is invalid. Check the --persona path and validate the JSON.

All requests return 500 Persona chat failed The underlying solver chain failed. Check solver plugin installation and their individual configs (API keys, model paths, etc.).

A2A endpoint not available after starting with --a2a-base-url a2a-sdk is not installed. Install it:

uv pip install 'ovos-persona-server[a2a]'

Then restart the server.

Embeddings return 501 No solver with get_embeddings() is loaded. Add an embeddings solver to the persona's solvers list.

Legacy /v1/ paths return responses with Deprecation header This is expected. Migrate to /openai/v1/ paths. See docs/deprecation.md.

Credits

Developed by TigreGótico for OpenVoiceOS.

This project was funded through the NGI0 Commons Fund, a fund established by NLnet with financial support from the European Commission's Next Generation Internet programme, under the aegis of DG Communications Networks, Content and Technology under grant agreement No 101135429.