6.3 Sealed Card Handoff Boundary Drills
chinwag card verify --input receipt.cwcard.pngHow Chinwag packages cryptographically signed task handoffs inside valid PNG trading cards (.cwcard.png) that traverse Slack, GitHub PRs, and corporate proxies intact.
6.3 Sealed Card Handoff Boundary Drills
chinwag card verify --input receipt.cwcard.png
Stanford's CooperBench research demonstrates that multi-agent engineering breaks down at the handoff boundary · the moment Agent A finishes a backend module and tries to explain its assumptions, edge cases, and verification state to Agent B (or a human reviewer) in unstructured chat prose.
Chinwag replaces lossy chat handoffs with .cwcard.png Sealed Handoff Cards: valid, human-readable PNG visual summary cards that carry a post-quantum X25519MLKEM768 + Ed25519 dual-signed binary handoff envelope (cWPK chunk) directly inside the PNG file structure.
# Seal a verified Shadow jj workspace handoff into a portable .cwcard.png card
chinwag cwcard seal \
--task TASK-204 \
--to "@ARCHITECT" \
--out ./artifacts/TASK-204-handoff.cwcard.png
Why a Valid PNG Carrier (.cwcard.png)?
- Human-Readable at a Glance: Drop
TASK-204-handoff.cwcard.pnginto a GitHub PR comment, Linear issue, or Slack thread and every engineer immediately sees a crisp visual card displaying the task ID,--file-scopelease,.codegraphblast radius,176/176UI gate badge, andMO-GRPO◈Chip stake. - Machine-Verifiable in
<20ms: Any authorized agent or teammate can pass the exact same.cwcard.pngfile (or URL) tochinwag cwcard unseal(50 Crfor a full two-round handoff conversation), which verifies the dualEd25519signatures in0.09ms, decrypts theRFC 9180 HPKEpayload via theACU, and mounts the exactShadow jjcommit tree and Negative Memory Tombstones in< 20ms. - Zero-Drop Proxy Traversal: Because
.cwcard.pngis a standards-compliant ISO/IEC 15948 PNG image (89 50 4E 47 0D 0A 1A 0A), corporate TLS inspection proxies, Slack file uploads, and GitHub issue attachments pass it through untouched without corrupting the ancillarycWPKcryptographic chunk.
Binary Anatomy of a .cwcard.png File
+-----------------------------------------------------------------------+
| PNG Signature (8 bytes): 89 50 4E 47 0D 0A 1A 0A |
+-----------------------------------------------------------------------+
| IHDR + IDAT Chunks: Crisp 1200×630 Visual Summary Card (Midnight UI) |
| Displays: Task ID, Owner <SEAT>#<INSTANCE>, Gate Status, ◈ Chips |
+-----------------------------------------------------------------------+
| cWPK Ancillary Chunk (Private, Safe-to-Copy PNG Chunk): |
| • Magic: "CHWGHPKE" (v2) |
| • OriginSigV1 (K1 Ed25519) + CloudRelayBlobSigV1 (K2 Ed25519) |
| • X25519MLKEM768 Encapsulated Key (1,120 bytes) |
| • ChaCha20Poly1305 Ciphertext: |
| - jj Revision Tree Hash & Patch Bundle |
| - H1..H5 Verification Receipts |
| - Active File-Scope Lease & Tombstone Warnings |
+-----------------------------------------------------------------------+
| IEND Chunk (12 bytes) |
+-----------------------------------------------------------------------+
Running a Boundary Handoff Drill
Teams practicing The Chinwag Way run weekly 3-minute Sealed Card Handoff Drills to ensure zero context loss across human-to-agent and agent-to-agent boundaries:
# Unseal a teammate's or partner agent's .cwcard.png into an isolated Shadow jj workspace
chinwag cwcard unseal ./artifacts/TASK-204-handoff.cwcard.png --verify-strict
[cwcard] Verifying outer K1+K2 Ed25519 signatures... PASS (0.09ms)
[cwcard] Decrypting X25519MLKEM768 HPKE payload... PASS (0.41ms)
[cwcard] Hydrating Shadow jj workspace at revision kkmpptxz (TASK-204)...
• Sender: @RUST#7f9a2c11e04b8821a930d4e11022bc04
• File Scope: crates/webhook-ingest/src/verify.rs (Disjoint lease verified)
• Attached Receipts: H1 cargo test (PASS), H3 clippy -D warnings (PASS)
• Boundary Constraint: "Verify signature BEFORE JSON deserialization"
[cwcard] Ready in 14.2ms (50 Cr).
Next Steps
- Next: 4-Minute
CaptionizmCalibration Scrimmages & The Zero-Knowledge Bridge - Ready for
<20mszero-loss agent handoffs? Reserve Your Organization Credit Pack →
Chips (◈) & 7-Day Survival
How Chinwag scores engineering outcomes across Quality, Review Velocity, Collaboration, and 7-Day Code Survival without vanity LOC gaming.
Calibration Scrimmages
How engineering squads run 4-minute Friday calibration scrimmages and bridge anonymized 20-byte MO-GRPO counters across the zero-knowledge wall.