Claude Managed Agents Sse Demo

claude-managed-agents-sse-demo

A tiny Python CLI that parses Server-Sent Events from Anthropic's **Claude Managed Agents** public-beta API (launched April 2026, beta header `managed-agents-2026-04-01`) into typed Python dataclasses and pretty-prints an agent session.

Runs **fully offline** against a bundled fixture — no API key, no install. An optional live mode streams real events if you have an API key and beta access.

Why

Claude Managed Agents shipped a managed harness for running Claude as an autonomous agent: secure sandboxed containers, long-running sessions, built-in tools (bash, file ops, web search), and a server-sent-event stream you read with `GET /v1/sessions/{id}/stream`. The wire format is small but lightly documented. This repo is a one-sit-read reference you can copy and extend: dataclasses that mirror the beta event schema, a tolerant SSE parser (ignores comments, buffers multi-line `data:` fields, drops malformed JSON), and a colorized terminal renderer.

Quickstart

python3 -m cma_sse replay fixtures/fibonacci.sse

That's it — the replay path is stdlib-only. Expected output (colors elided):

-- session: running --
I'll create a Python script that generates the first 20 Fibonacci numbers and saves them to fibonacci.txt.
[tool] write  {"path": "fibonacci.py", "content": "a,b=0,1 ..."}
[tool-ok] Wrote fibonacci.py (96 bytes)
[tool] bash  {"command": "python fibonacci.py && wc -l fibonacci.txt"}
[tool-ok] 20 fibonacci.txt
...
-- session: idle --

{
  "events": 10,
  "by_type": { "session.status": 2, "agent.message": 2, "agent.tool_use": 3, "agent.tool_result": 3 }
}

Optional — stream a live session (you must have already created an agent, environment, and session per the [quickstart](https://platform.claude.com/docs/en/managed-agents/quickstart)):

pip install -r requirements.txt
export ANTHROPIC_API_KEY=...
python3 -m cma_sse live --session-id sess_... --prompt "Say hi"

Event model

| Wire `type`