Open Protocol + Toolkit

Verifiable Handoffs For Agents

Agent Capsule wraps machine payloads in a text-native envelope so receivers can ingest, verify, policy-check, and unpack safely across existing channels.

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2-minute proofpython3 -m pip install agentcapsule
agentcapsule pack handoff.json --out capsule.txt
agentcapsule ingest thread.txt --out ./sandbox --strict --json

Strict mode exits non-zero on malformed or invalid ingestion. Use it as a CI/governance gate.

What Changes

Typical agent threads are lossy for machine payloads. Agent Capsule turns handoffs into verifiable artifacts.

Before

Payloads move as free-form text and can be truncated, reformatted, or silently edited.

After

Receivers verify `capsule_sha256`, `payload_sha256`, signature/trust policy, then unpack to sandbox.

Adoption

One command and one function: `agentcapsule ingest ...` and `ingest_messages(...)`.

Protocol Shape

Capsule

Exact payload bytes plus metadata and verification context.

Envelope

Text wire format with boundaries, headers, and encoded payload.

Manifest

Handoff intent: creator, task ID, files, capabilities, policy hints.

Delivery

Inline, attachment, or reference (URI + capsule hash + payload hash).

Agent Capsule is not a transport platform. It travels through chat, email, tickets, GitHub, A2A/MCP, and object storage.

Safe Receiver Order

Scan inbound text for capsules/references.
Apply local policy checks.
Fetch references and verify descriptor hashes.
Verify capsule metadata, integrity, and trust policy.
Unpack only verified payloads into sandbox.

Practical Start

Start with base64 + SHA256 verification. Add signatures, trust registry, encryption, compression, and resumable fetch when needed.

Quickstart Receiver Guide Protocol Spec