v0.2.0 — session-scoped backends, live streaming, 14 ACP backends

Highlights

The stdio ACP server works end-to-end now. Session updates are delivered through the connection's session_update API, and serve() awaits acp.run_agent (a coroutine since SDK 0.11). Verified with a full round-trip: external ACP client → framework server → real backend CLI → response streamed back.

Session-scoped backends. Backend processes spawn once per session and stay warm across turns — no more cold start per prompt. The backend's own session carries conversation continuity, so multi-turn no longer replays history as text. Context.close(), the ACP close_session method, and HTTP session deletion release resources; a crashed backend is detected and respawned transparently.

Real streaming. prompt_stream() yields chunks live while the backend is generating. Response text is now typed: only agent message chunks count, so model reasoning (thought chunks) no longer leaks into user-visible output.

14 pre-registered backends (up from 3): claude, gemini, codex, copilot, opencode, goose, qwen, cursor, grok, cline, auggie, kilo, devin, kimi — launch commands mirror the official ACP Registry manifests. Anything else in the registry can be added with BackendRegistry().register(...).

Hardening. Spawn failures clean up whatever was started; runs of the same agent on one session are serialized so concurrent prompts can't double-spawn or interleave; a missing backend CLI fails preflight with a clear message; guardrail-transformed final text reaches streaming clients; Context.close() closes every resource even when one fails.

Breaking changes

• Requires agent-client-protocol >= 0.11.
• The openai and ollama placeholder backends were removed (no such binaries exist). The gemini backend now launches with --acp.
• Backends are no longer stopped after each prompt. Long-lived scripts embedding agents directly should call await ctx.close() when done with a session; the servers handle it automatically.

Upgrade

pip install -U acp-agent-framework

Claude and Codex adapter installs moved orgs: npm i -g @agentclientprotocol/claude-agent-acp / @agentclientprotocol/codex-acp.

Full details in CHANGELOG.md. 184 tests, CI green on Python 3.10–3.12.

v0.1.1

Fix README images on PyPI (use absolute URLs).

v0.1.0

ACP Agent Framework v0.1.0

Initial release of the first open-source Python framework for building agents that speak the Agent Client Protocol (ACP).

Features

• Agents: Agent, SequentialAgent, RouterAgent, ToolAgent
• Backends: Claude, Gemini, Codex — swap with a single parameter
• Tools: Wrap any Python function as an MCP tool for LLM calling
• Streaming: Real-time token-by-token output
• Multi-turn: Conversation history across prompts
• Guardrails: Input/output validation hooks
• Agent-to-agent: Delegate tasks between agents via AgentTool
• Skills: Load reusable capabilities per agentskills.io spec
• Serving: ACP stdio, HTTP/SSE, CLI

Install

pip install acp-agent-framework