dagent-ai 0.2.2

Human-reviewed Agent DAG framework

dagent

Plan globally. Re-plan locally.

dagent is a Dynamic DAG Agent framework. It can automatically route a request, run it through a bounded tool-using agent, or use a planner that creates and executes a reviewable capability-node DAG. Each public agent object is declarative configuration, while Runner owns the runtime session, capability catalog, review continuations, and execution state.

Traditional agent frameworks choose one of two extremes: a free-running ReAct loop with no structure, or a rigid static pipeline with no adaptability. dagent rejects both. Every task that needs orchestration gets a reviewable, auditable plan up front. That plan can evolve from DAG observations as execution proceeds, while completed tool results remain structured execution records.

Design origin: The self-planning dynamic DAG agent loop - capability-node DAG with three-level incremental re-planning, Trace DB as the long-term context boundary, human review checkpoints, DAG-vs-tool task routing, and resumable execution - was conceived and first implemented by the author of this repository. First committed: 2026-05-01.

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Core Ideas

1. Reviewable plans, not opaque loops. Tasks that need orchestration become capability-node DAGs before execution. The plan is typed, inspectable, and can pause for human review before risky work runs.

2. Typed nodes with direct capability calls. Every DAG node has a typed payload. Capability nodes wrap a CapabilityInvocation; start nodes are explicit and do not carry fake tool calls. The runtime executes capabilities through a shared CapabilityExecutor.

3. Structured parameter passing between nodes. Static DAG arguments can reference graph input, upstream node results, and artifact paths. These references are structured $expr bindings in DAGSpec, resolved immediately before a capability call. A node that reads another node's output must explicitly depend on it.

4. Re-planning stays local. After each executable DAG layer, the planner receives a DAG observation and can return NO_CHANGE, a revised PlanSpec, or a final answer. Completed node results stay as structured execution records instead of being rediscovered from chat history.

5. Runner owns runtime state. Public AutoAgent, ToolAgent, DagAgent, and Dag objects are declarative configuration. Runner owns the provider, capability catalog, session state, review continuations, and execution dispatch.

6. Safety is part of execution, not prompting. The DAG planner proposes work, but capability handlers enforce boundaries before side effects. Medium/high-risk work can require review; disabled or unknown capabilities fail closed; file boundaries reject path escape.

Quick Start

Install the PyPI package as dagent-ai; import it in Python as dagent:

pip install dagent-ai

Pass SDK configuration explicitly to the runner:

import dagent


@dagent.tool
def search(q: str) -> str:
    return f"found:{q}"


provider = dagent.Provider(
    base_url="https://api.openai.com/v1",
    model="your-model",
    api_key_env="OPENAI_API_KEY",
)

runner = dagent.Runner(
    workspace=".",
    provider=provider,
    capabilities=[search],
    mcp_servers={
        "fs": {
            "command": "npx",
            "args": ["-y", "@modelcontextprotocol/server-filesystem", "."],
        },
    },
    skill_roots=["team-skills"],
    profile_root="profiles",
)

Use Runner.from_config(...) when provider settings, MCP servers, validation, or profile directories should come from a config file:

runner = dagent.Runner.from_config("config.yaml", workspace=".", capabilities=[search])

The same capability types can be added after runner construction:

@dagent.tool
def summarize(text: str) -> str:
    return text.split(".")[0]


runner = dagent.Runner(provider=provider, workspace=".")
runner.add_tool(summarize)
runner.add_mcp_server(
    "fs",
    {
        "command": "npx",
        "args": ["-y", "@modelcontextprotocol/server-filesystem", "."],
    },
)
runner.add_skill_root("more-skills")
runner.skill_store.install(
    "Keep every answer compact.",
    name="terse",
    description="Compact response style.",
    category="writing",
)

Runtime MCP registrations can be replaced or removed without touching agent configuration:

runner.replace_mcp_server(
    "fs",
    {
        "command": "npx",
        "args": ["-y", "@modelcontextprotocol/server-filesystem", "docs"],
    },
)
runner.remove_mcp_server("fs")

Python tools are exposed as tool.<name> capabilities. MCP stdio server tools are exposed as mcp.<server>.<tool> and require the MCP optional extra. Skill roots are available through the built-in skill.list and skill.view capabilities. Agents use skills=[...] to limit which concrete skills those accessors can see.

Built-in profiles are packaged resources. Use them by name on agents, or read them directly when you need to inspect the prompt:

agent = dagent.ToolAgent(profile="conversation")
profile = dagent.load_builtin_profile("conversation")
available = dagent.list_builtin_profiles()

Run an AutoAgent when the runtime should choose direct tool use or a dynamic DAG per request:

import asyncio

import dagent


@dagent.tool
def search(q: str) -> str:
    return f"found:{q}"


async def main():
    runner = dagent.Runner(provider=provider, workspace=".", capabilities=[search])
    agent = dagent.AutoAgent(capabilities=["tool.search"], skills=["writing/terse"])

    result = await runner.run(agent, "Answer directly or plan if orchestration helps.")
    print(result.kind)
    print(result.output_text)


asyncio.run(main())

Run a ToolAgent for bounded tool-loop work:

import asyncio

import dagent


@dagent.tool
def echo(text: str) -> str:
    return f"echo:{text}"


async def main():
    runner = dagent.Runner(provider=provider, workspace=".", capabilities=[echo])
    agent = dagent.ToolAgent(
        profile="conversation",
        capabilities=["tool.echo"],
        skills=["writing/terse"],
    )

    result = await runner.run(agent, "Use echo to respond with hello.")
    print(result.output_text)
    print(result.model_dump(mode="json"))


asyncio.run(main())

Run a DagAgent when the model should plan a reviewable DAG:

import asyncio

import dagent


@dagent.tool
def search(q: str) -> str:
    return f"found:{q}"


async def main():
    runner = dagent.Runner(provider=provider, workspace=".", capabilities=[search])
    agent = dagent.DagAgent(capabilities=["tool.search"], review="careful")

    result = await runner.run(agent, "Research dagent and write a short note.")
    if result.requires_review and result.review is not None:
        result = await runner.resume(result.review.approve())

    print(result.output_text)


asyncio.run(main())

Build a static Dag when the graph shape belongs in code:

import asyncio

from pydantic import BaseModel

import dagent


class ResearchInput(BaseModel):
    query: str
    audience: str = "engineers"


class SearchResult(BaseModel):
    title: str
    url: str


@dagent.tool
def search(q: str) -> SearchResult:
    return SearchResult(title=f"found:{q}", url="https://example.test")


@dagent.tool
def render(title: str, url: str, audience: str) -> str:
    return f"{title} for {audience}: {url}"


async def main():
    dag = dagent.Dag("research", input=ResearchInput)
    found = dagent.Node("search", target=search, inputs={"q": dag.input.query})
    rendered = dagent.Node(
        "render",
        target=render,
        inputs={
            "title": found.output.title,
            "url": found.output.url,
            "audience": dag.input.audience,
        },
    )
    dag.add_node(found)
    dag.add_node(rendered)
    dag.add_edge(found, rendered)

    dagent.validate_dag_spec(dag.to_dag_spec())

    runner = dagent.Runner(provider=provider, workspace=".")
    result = await runner.run(dag, input=ResearchInput(query="dagent"))
    print(result.status)
    print(result.node_output("render"))


asyncio.run(main())

Runner.run(...) always returns RunResult, including static Dag and DAGSpec runs. Customize static DAGs with Pydantic graph inputs, typed tool return values, explicit dag.add_edge(...) dependencies, artifact references, and per-node boundaries. See the Python SDK guide for the full SDK.

Run examples:

uv run python -m examples.tool_agent
uv run python -m examples.auto_agent
uv run python -m examples.dynamic_dag_agent
uv run python -m examples.static_dag
uv run python -m examples.streaming
uv run python -m examples.runtime_registration_and_skills

Run the test suite:

uv run --extra dev pytest

Detailed SDK docs live in the Python SDK guide.

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Architecture

flowchart TD
  U["User / SDK"] --> RUN["Runner"]
  RUN --> HR["HarnessRuntime"]
  HR -->|"AutoAgent routes to tool"| TA["ToolAgent"]
  HR -->|"ToolAgent target"| TA
  HR -->|"AutoAgent routes to DAG"| DA["DAGAgent"]
  HR -->|"DagAgent target"| DA
  HR -->|"Dag / DAGSpec target"| DS["DAGSpec"]

  TA --> TAL["ToolAgentLoop"]
  TAL -->|"capability call"| CE["CapabilityExecutor"]

  DA --> DAL["DAGAgentLoop"]
  DAL -->|"PlanSpec DSL"| DAG["DAG"]
  DS -->|"compile"| DAG
  DAG --> RG["Review Gate"]
  RG --> DE["DAGExecutor"]
  DE -->|"ready layer"| CE
  CE --> CAT["Capability Catalog"]
  CE --> RT["RunTrace + Artifacts"]
  RT --> OBS["DAG Observation"]
  OBS --> DAL
  HR --> RR["RunResult"]

Runner is the public SDK entrypoint and owns the configured runtime, session, and capability catalog. HarnessRuntime is the lower-level control layer for routing, review continuations, optional result validation, and final response delivery.

AutoAgent lets the runtime route each request to direct tool use or dynamic DAG planning. ToolAgent delegates bounded tool-loop work to ToolAgentLoop. DAGAgent delegates dynamic planning and fixed DAGSpec execution to DAGAgentLoop. Both paths share CapabilityExecutor, so Python tools, MCP tools, skill accessors, shell commands, file tools, memory, and agent capabilities go through the same catalog and boundary enforcement.

DAGExecutor validates graph structure, resolves structured value expressions, executes ready layers, updates artifact state, and returns a cumulative RunTrace.

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Project Layout

api/               local FastAPI backend for the WebUI
dagent/
  capabilities/     capability catalog, providers, adapters, and built-in handlers
  harness_runtime/  runtime orchestration, agent loops, validation, session state,
                    event adapters, DAG execution
  providers/        OpenAI-compatible and mock chat providers
  resources/        packaged default Markdown profiles
  schemas/          DAG, node, edge, trace, feedback, result/outcome contracts
  state/            prompt assembly
web/                React + Vite frontend
tests/              pytest suite

Key runtime contracts such as RunTrace, LoopOutcome, RuntimeResponse, PendingReview, and validation result types live in dagent/schemas. harness_runtime owns behavior; schemas owns shared data contracts.

Documentation

• Python SDK guide
• Runnable examples

License

Apache License 2.0. See LICENSE.