crewai-zambo

AER-1, the agent execution receipt standard: zambo.dev/aer-1 | Add Zambo to your AI: zambo.dev/add

Zambo is the verifiable work layer for AI. This package publishes CrewAI task events as verifiable AER-1 receipts at zambo.dev.

Receipt format: AER-1, IETF Internet-Draft draft-zambo-aer1-26.

Verifiable AER-1 execution receipts for CrewAI agents. Publish CrewAI task events as public, verifiable receipts at zambo.dev.

Receipts follow AER-1, the IETF draft for verifiable execution receipts created by Brennan Zambo.

Install

pip install crewai-zambo

Ten-line example

from crewai_zambo import ZamboCrewListener

listener = ZamboCrewListener()
result = listener.on_task_completed("Summarize this task", "completed")
print(listener.last_receipt_url or result)

Attach ZamboCrewListener to the CrewAI listener mechanism supported by your installed CrewAI version, or call on_task_completed from a task completion hook. The listener prints each public https://zambo.dev/run/{id} URL and keeps the most recent URL in last_receipt_url.

The receipt describes what the live endpoint recorded and observed. It does not prove an outside outcome that the endpoint did not observe. Set ZAMBO_API_URL when using a compatible Zambo host. Listener failures are available in receipt_errors.

Local AER-1 receipts (no network needed)

The package also mints AER-1 execution receipts locally, with no API calls. Pass emit_aer1=True to record every event as a verifiable receipt on your own machine:

from crewai_zambo import ZamboCrewListener

listener = ZamboCrewListener(emit_aer1=True)
listener.on_task_completed("Summarize this task", "completed")

receipt = listener.last_local_receipt
print(receipt["id"], receipt["output_hash"])

Or mint receipts directly for any tool call:

from crewai_zambo import mint_receipt, verify_receipt

receipt = mint_receipt("my_tool", {"query": "hello"}, {"answer": "hi"}, ms=42)
assert verify_receipt(receipt)  # recomputes the SHA-256 locally

Local receipts follow the AER-1 core members (id, created_at, tool, provenance_class, canonical_bytes, output_hash) and use the provenance class EXECUTED BY CREWAI-ZAMBO, naming this package as the recording system. They pass the same hash-recomputation check as any AER-1 receipt.

Project homepage: https://zambo.dev AER-1 receipt spec: https://zambo.dev/aer-1/

Guides

• Execution Receipts for AI Agent Frameworks
• What Is an AI Agent Execution Receipt?

Where these receipts run live: Zambo

crewai-zambo publishes every CrewAI task event as a verifiable AER-1 receipt at zambo.dev, and it has been downloaded 5,308 times on PyPI. The live home of those receipts is Zambo, the verifiable work layer for AI. Connect any AI to the live endpoint at https://zambo.dev/mcp or add Zambo to your AI in one step at https://zambo.dev/add/

Free tier: 20 calls + 1 wrap-up free every day; picking up in another AI is always free. The Day Pass is $0.99 for 24 hours, unlimited.

Install:

pip install crewai-zambo