Friday Agent SDK for Python

Status: alpha — APIs may change. Pin an exact version in production.

Write AI agents in Python that run inside the Friday platform. The host manages credentials and routes LLM, HTTP, and MCP calls on the agent's behalf, so your agent code stays a pure Python function — no provider SDKs, no key plumbing in your code.

The SDK on its own is not runnable: agents need the Friday daemon to host them and an LLM provider key configured on the daemon. See Prerequisites below.

Prerequisites

• Python 3.12+
• The Friday daemon and atlas CLI — install via friday-platform/friday-studio. Follow that repo's quickstart to clone, install, configure an LLM provider key, and run deno task atlas daemon start --detached. Verify it's up:

  curl -sf http://localhost:8080/health && echo "  daemon ok"
  

• An LLM provider API key (Anthropic, OpenAI, or Google) configured in the daemon's .env — see Friday Studio's .env.example for the full list.

Daemon ports. Friday exposes two HTTP services: the daemon API and Friday Studio. The defaults depend on how you ran Friday:

Mode	Daemon API	Friday Studio
Running from source	:8080	:5200
Installer / Docker	:18080	:15200

Examples in this README use the source-code ports. If you installed Friday via the installer or Docker, replace 8080 → 18080 and 5200 → 15200.

Quickstart

Install the SDK from PyPI:

pip install friday-agent-sdk
# or, with uv:
uv add friday-agent-sdk

Create an agent directory:

mkdir -p agents/my-analyzer

Write agents/my-analyzer/agent.py:

from friday_agent_sdk import agent, ok, AgentContext, run

@agent(
    id="my-analyzer",
    version="1.0.0",
    description="Analyzes text with an LLM",
)
def execute(prompt: str, ctx: AgentContext):
    result = ctx.llm.generate(
        messages=[{"role": "user", "content": f"Summarize this: {prompt}"}],
        model="anthropic:claude-haiku-4-5",
    )
    return ok({"summary": result.text})

if __name__ == "__main__":
    run()

Register your agent with the daemon:

atlas agent register ./agents/my-analyzer

Test it:

atlas agent exec my-analyzer -i "Summarize this codebase"

Or via the playground API:

curl -s -X POST http://localhost:5200/api/agents/my-analyzer/run \
  -H 'Content-Type: application/json' \
  -d '{"input": "Summarize this codebase"}'

Documentation

• Tutorial: Your First Friday Agent — Complete walkthrough from zero to running agent
• How-to Guides — Task-focused recipes for common patterns
  • Call LLMs from your agent
  • Make HTTP requests
  • Use MCP tools
  • Handle structured input
  • Stream progress updates
• API Reference — Complete decorator, context, and capability documentation
• How Friday Agents Work — Architecture and design decisions (optional reading)

Installation

The SDK is published to PyPI as friday-agent-sdk:

pip install friday-agent-sdk
# or with uv
uv add friday-agent-sdk

To install from a clone of this repo (e.g. when working on the SDK itself):

cd packages/python
uv sync --all-extras --dev
# or: pip install -e .

Examples

See examples/ for complete agents ranging from minimal to production-grade. examples/README.md has the full annotated index, including required env vars.

Testing

Run unit tests for the Python SDK:

cd packages/python
pytest

Advanced usage

Custom entry points

If your agent file is not named agent.py, specify the entry point during registration:

atlas agent register ./my-agent --entry main.py

Or via the API:

curl -s -X POST http://localhost:8080/api/agents/register \
  -H 'Content-Type: application/json' \
  -d '{"entrypoint": "/path/to/my-agent/main.py"}'

Direct execution API

For CI/CD pipelines or automation, execute agents via the daemon API:

curl -s -X POST http://localhost:8080/api/agents/my-agent/run \
  -H 'Content-Type: application/json' \
  -d '{"input": "test prompt"}'

Error responses include the phase that failed (prereqs, validate, write):

{ "ok": false, "phase": "validate", "error": "description is required" }

Limitations

• No streaming LLM responses — ctx.llm.generate() blocks until the full response is ready
• One agent per file — Each .py file registers exactly one @agent
• 5MB HTTP response limit — Matches Friday's platform webfetch limit
• Spawn-per-call — Each execution starts a fresh process; keep startup lightweight

Troubleshooting

Registration fails with "validate timeout" The daemon spawns your agent to collect metadata and waits up to 15s. Check that run() is called in __main__ and that the daemon is running.

Agent not appearing after registration Check that registration succeeded: atlas agent list. Agents are stored in ~/.friday/local/agents/.

Registration returns 400 Your @agent decorator metadata failed validation. Required fields: id, version, description.

Execution hangs The agent may not be signaling readiness before the daemon sends the execute request. Verify run() is called.

Import errors in IDE The friday_agent_sdk package must be installed in your active Python environment (pip install friday-agent-sdk, or pip install -e . when working from a clone) for type checking and autocomplete.

License

MIT