How to manage artifacts and persistent outputs in Google ADK?

Artifacts in Google ADK

Artifacts are persistent outputs (files, reports, code, images) that agents produce during execution. They are versioned and stored alongside the session.

Artifact Lifecycle

Saving Artifacts

pythonCopy
from google.genai import types

async def generate_report(query: str, tool_context) -> str:
    """Generate and save a report as an artifact.

    Args:
        query: The topic to report on.
    """
    report = f"# Report: {query}\n\nFindings: ..."

    artifact = types.Part.from_data(
        data=report.encode(),
        mime_type="text/markdown"
    )
    version = await tool_context.save_artifact("report.md", artifact)
    return f"Report saved (version {version})"

async def save_chart(data: dict, tool_context) -> str:
    """Save a chart image as an artifact."""
    import matplotlib.pyplot as plt
    import io

    fig, ax = plt.subplots()
    ax.bar(data.keys(), data.values())
    buf = io.BytesIO()
    fig.savefig(buf, format="png")

    artifact = types.Part.from_data(
        data=buf.getvalue(),
        mime_type="image/png"
    )
    version = await tool_context.save_artifact("chart.png", artifact)
    return f"Chart saved (version {version})"

Loading Artifacts

pythonCopy
async def review_report(tool_context) -> str:
    """Load and review a previously saved report."""
    artifact = await tool_context.load_artifact("report.md")

    if artifact is None:
        return "No report found."

    content = artifact.data.decode()
    return f"Report content:\n{content}"

Artifact Versioning

pythonCopy
# Each save creates a new version
v1 = await tool_context.save_artifact("draft.md", draft_v1)  # version 0
v2 = await tool_context.save_artifact("draft.md", draft_v2)  # version 1

# Load latest version (default)
latest = await tool_context.load_artifact("draft.md")

# Load specific version
v1_content = await tool_context.load_artifact("draft.md", version=0)

Common Artifact Types

text/plain

text/markdown

application/json

text/csv

application/pdf

image/png

text/x-python

Learn more at Sessions & Artifacts.