pydantic-acp 0.4.0

ACP adapter for pydantic-ai agents.

pydantic-acp

pydantic-acp adapts pydantic_ai.Agent instances to the ACP agent interface.

Public Entry Points

• run_acp(...)
• create_acp_agent(...)
• AdapterConfig
• AcpSessionContext
• AgentSource, AgentFactory, StaticAgentSource, FactoryAgentSource
• AgentBridgeBuilder
• provider protocols
• capability bridges
• hook projection and existing-hook introspection
• host backends

Implemented Scope

• Milestone 1-7 scope is implemented
• the adapter includes session lifecycle, session-local model control, providers, approvals, bridges, projection maps, and host backends
• slash commands are available for /model, /tools, /hooks, and /mcp-servers

Quick Start

from pydantic_acp import run_acp
from pydantic_ai import Agent

agent = Agent("test", name="demo-agent")
run_acp(agent=agent)

Factory-backed usage:

from pydantic_acp import AcpSessionContext, create_acp_agent
from pydantic_ai import Agent

def build_agent(session: AcpSessionContext) -> Agent[None, str]:
    return Agent("test", name=f"demo-{session.cwd.name}")

acp_agent = create_acp_agent(agent_factory=build_agent)

File-backed session persistence:

from pathlib import Path

from pydantic_acp import AdapterConfig, FileSessionStore, run_acp

run_acp(
    agent=agent,
    config=AdapterConfig(
        session_store=FileSessionStore(base_dir=Path(".acp-sessions")),
    ),
)

Projection map example:

from pydantic_acp import FileSystemProjectionMap, run_acp

run_acp(
    agent=agent,
    projection_maps=(
        FileSystemProjectionMap(
            default_read_tool="read_file",
            default_write_tool="write_file",
            default_bash_tool="execute",
        ),
    ),
)

Hook projection example:

from pydantic_acp import HookProjectionMap, run_acp

run_acp(
    agent=agent,
    projection_maps=(
        HookProjectionMap(
            hidden_event_ids=frozenset({"after_model_request"}),
        )
    ),
)

Major Features

• ACP session lifecycle support
• transcript and model-message history replay
• generic tool projection with ACP tool updates
• projection maps for filesystem diffs and bash command previews
• session-local models, modes, config options, and plan updates
• deferred approval bridging
• provider seams for host-owned state
• capability bridges for hooks, history processors, prepare-tools, and MCP
• hook introspection and HookProjectionMap rendering for existing Hooks capabilities
• session-scoped host backends

Examples

See examples/pydantic/ for focused SDK examples covering static agents, factories, providers, bridges, approvals, host-context usage, and hook projection.

Key entry points:

• examples/pydantic/hook_projection.py
• examples/pydantic/my_agent.py

For fuller workspace documentation, see the root README.md and the docs/ directory.