PQ Interop #24 | Jan 28, 2026

[will-corcoran]

Resources

• Zoom link: https://ethereumfoundation.zoom.us/j/4840114962?pwd=S8FArsXkTutjZDmVohZ7b0VOCaY4An.1
• Facilitator email: will@ethereum.org
• Facilitator Telegram: @corcoranwill
• Telegram: PQ Interop — threads: #general, #devnet-1, #devnet-2, #devnet-3, #tooling, #leanVM, #onboarding

High-Level Documents

• Devnet-0 : lean consensus client interop
• Devnet-1 : PQ signature signing & verification
• Devnet-2 : single-layer PQ signature aggregation ✅ LAUNCHED
• Devnet-3 (Draft PR #56) : aggregator role separation + subnet aggregation

Overview

A. Devnet-2: Implementation Status (Devnet N)
B. Devnet-3: Specification Status (Devnet N+1)
C. New Client Onboarding
D. Tooling & Infrastructure
E. Schedule / Next Steps

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Previous Call Meeting Minutes (Call 23 — Jan 21, 2026)

A. Devnet-2: Implementation Status

🚀 Devnet-2 is now live.

Client Readiness

Client	Devnet-2 Status	Interop	Docker Image	Notes
Zeam	✅ Complete	✅ Ready	✅	PQ metrics added. Reviewing Devnet-3 PRs.
Ream	🔶 Near-complete	🔶 Testing	🔶	Minor struct differences (aggregated signature storage). Adding spec tests to CI. Syncing implemented.
Qlean	🔶 In progress	🔶 Pending	🔶	OOM fix merged. Stabilized networking (peer disconnect handling). Merging recent spec changes.
Lantern	🔶 In progress	🔶 Pending	🔶	Checkpoint sync implemented. Aligning with leanSpec sync logic. Debugging sync stalling on long-running devnets. Implementing justification pruning (PR 305).
Lighthouse	❓ Unknown	—	—	No representative on call.
Grandine	—	—	—	No update provided.
Nimbus	🆕 Starting	—	—	New. nim-leansig implementation begun.

Spec/Implementation Issues Raised

• Block building state root mismatch (Sharik/Ream): compute_aggregated_signature may produce different attestation bits than what's in candidate_block, but post_state_root doesn't reprocess. Causes assertion failures at state transition. Action: Sharik to add test vector and open issue on leanSpec.
• Aggregated attestation validation check: Gajinder noted a check was removed from spec (duplicate attestation bits across aggregated payloads). Ream may have stale validation logic.
• leanMultisig/leanSig compatibility: Two spec changes after Devnet-2 commit merge—Montesig compatibility fix (Emil) and justification refactor. Ensure clients pull latest commits.
• API mismatch in leanMultisig (Issue ACD Meeting 74 Notes #136): Prover state constructor changed from 2 args to 1. Believed fixed, but Percy to verify.

Devnet-2 Tooling

• Docker image labels needed: Katya requesting commit hash metadata for easier identification
• Peer connection metrics: Labels available—please implement for connection debugging
• Default images issue: Open issue linked to leanQuickStart update
• leanQuickStart config files: Coming for easier local devnet launch

B. Devnet-3: Specification Status

Key PRs Under Review

PR	Description	Status
PR #56	High-level Devnet-3 plan	Draft
PR #58	compute_subnet_id() function	Open
Committee aggregation spec (Kamil)	Subnet aggregation logic	In progress

Breakout Call (Jan 22)

• Topic: Devnet-3 spec PR discussions
• Time: 2pm UTC
• Contact: DM Gajinder or Unnawut for invite

Research Updates

• leanSpec minimal client (Thomas): Added P2P, database, storage, validators CLI modules (no external dependencies). Waiting on Python bindings for signature aggregation to enable interop. Focus: test coverage, minimal client completion.
• leanSpec PDF companion (Thomas): Started a plain-English specification document with explanations and diagrams. Sections complete: intro, timing system, SSZ.
• ZK-DSL → Python syntax (Emil): Recursion/XMSS aggregation compiler DSL now Python-like syntax. Goal: same Python source serves as both spec and compiles to low-level Lean ISA.
• leanMultisig presentation (Unnawut): Comprehensive walkthrough delivered — [link TBD]
• Claude AI agents (Thomas): Sub-agents for documentation, code compliance, test verification now in leanSpec repo (.claude/ folder). Open for community modification.

C. New Client Onboarding

Client	Status	Current Milestone
Ethlambda	Devnet-1 complete	Testing interop with leanQuickStart + leanSim. PR open for leanQuickStart support. Next: Devnet-2, historical sync, DB persistence.
Gean	Starting	Type system, serialization, clock, genesis implemented. Next: state transition.
Nimbus	Starting	nim-leansig implementation begun.

Onboarding resources:

• Target specific devnet commit in leanSpec versioning file
• Use #onboarding thread in Telegram for questions
• Tag Katya for leanQuickStart integration help
• Logs are essential — even without metrics, logs help debug failures

D. Tooling & Infrastructure

Devnet-1 Retrospective

• Finalized: Published in leanQuickStart repo
• Link to retrospective

GitHub Organization Improvements

• Milestones & labels: All PRs now tagged by devnet milestone for filtering
• Example filter: Devnet-2 PRs
• Readiness checklists: To be merged into high-level devnet docs

Telegram Consolidation

• Launched: PQ Interop Telegram supergroup with threads
• Threads: #general, #devnet-1, #devnet-2, #devnet-3, #tooling, #leanVM, #onboarding
• Goal: Reduce channel fragmentation, enable focused discussions per devnet

E. Schedule / Next Steps

• Next call: January 28, 2026 (Wednesday)
• Breakout call: January 22, 2pm UTC — Devnet-3 spec discussion

Action Items

Owner	Action	Deadline
Sharik (Ream)	Add test vector for block building state root issue, open leanSpec issue	Next call
Percy	Verify leanMultisig API mismatch fix (Issue #136)	Next call
All clients	Add Docker image labels with commit hashes	Ongoing
All clients	Implement peer connection metrics	Ongoing
New clients	Add logging even if metrics not ready	Ongoing
Katya	Share Devnet-2 Grafana dashboards	Soon
Lantern	Release Devnet-2 Docker image after tooling update	This week

Coordination Process Changes (Agreed)

1. Two-devnet model: Focus on Devnet N (implementation) + Devnet N+1 (specification) only
2. Call structure: Reorganized around devnet phases, not personas
3. Telegram threads: Use devnet-specific threads to avoid cross-talk confusion
4. PR hygiene: All PRs tagged with devnet milestone
5. Retro at Cannes: Full coordination review when teams meet in person (March)

[bomanaps]

Adding this here so client teams can review leanEthereum/pm#68

[KatyaRyazantseva]

Correct Devnet-1 retrospective link