amethyst/quartz/plans/2026-09-29-concord-spec-conformance.md

Concord spec conformance review (spec b84554e, 2026-08-15)

Why

Our Concord implementation last tracked the spec at bbc67b6 (2026-08-06, CORD-02 §2 control_root). Since then the spec moved on, and several sections that predate that point were never implemented. This review compares every CORD against https://github.com/concord-protocol/concord at b84554e, cross-checked against the Armada reference client (soapbox-pub/armada at 7588884, 2026-09-28), and records what we fixed and what is left.

Method: one audit per spec area (CORD-01/03, CORD-02 §2/§5/§6 + CORD-04, CORD-02 §7/§9 + CORD-05/06, CORD-07/08), each reading our code against the spec text and against Armada. CORD-02 §8 (the Community List) was reviewed by hand against Armada's listFrag.ts / communityList.ts. Status legend: fixed (this branch, with tests), open (not done, with the reason).

What changed upstream since our last pass

Commit	Date	Change	Our state before this review
d584686	07-27	CORD-02 §9: the dissolution tombstone's eid is the community_id; verifiers MUST refuse anything else, including the old all-zero eid	Not implemented at all: we never derived dissolved_pk, never read or wrote a tombstone, and folded a vsk-10 Control Plane edition as dissolution with no eid check
e8c4eeb	08-02	CORD-04 §7: provable, rotation-proof Pins (vsk 11, PIN_MESSAGES bit 11, concord/pins coordinate, NIP-44 key-disclosure proof bundles)	Missing (only the permission bit existed)
93fbecf	08-03	CORD-08: Disappearing Messages (message_expiration in metadata, NIP-40 tags on rumor + wrap, kind 1740 timer notice)	Missing, and worse: a metadata edit dropped the field, silently turning off Armada's default 30-day timer for everyone
96f0647, bbc67b6	08-06	CORD-02 §2 control_root write gate	Implemented (v1.14.0)
759448a, ee6f639	08-11/15	CORD-02 §8: the Community List becomes fragmented kind 33302 (13302 retired), unpadded base64url for every 32-byte value, seed omitted when equal to current, mandatory tombstones, read-modify-write, a byte ceiling instead of a 50-entry cap	Still on 13302, hex, no tombstones (leaving just dropped the entry)
01.md	08-11	Encrypted application documents may choose their own encoding (only §8 does)	n/a

Still-open upstream PRs worth tracking: #23 (authenticate community_root at accept; would make our stranded-recovery root move an explicit MUST violation), #22 (community-owned av_brokers in metadata), #17 (Community Signals, vsk 12), #16 (CORD-09 blinded mention locators), #7 (drop the ms tag). #12 (split read/write planes) is superseded by the merged control_root design.

Findings

Ranked security > interop > feature inside each group.

Security

#	Spec	Finding	Status
S1	02 §9	Dissolution: no dissolved_pk plane, no eid binding, spec tombstone (chainless, no ev) could not even parse; a vsk-10 Control Plane edition dissolved with no binding check	fixed — ConcordDissolution (derive, build, verify with eid == community_id, 20014 seal, owner author); session + planner subscribe the plane; CLI amy concord dissolve; the Control Plane fold no longer reads vsk 10
S2	03 §1-2	Posts into a private:true channel go to the root-derived plane every member can decrypt, under a Lock icon; real private channels can't be read	fixed — ConcordActions.currentChannelPlane/historicalChannelPlanes derive a private channel only from the entry's held privateChannels key at its channel epoch (never the root plane); session, planner, plane registry, app verbs and CLI all go through it; a keyless private channel has no plane (ConcordChannel.keyHeld/canPost() false, composer replaced by a notice, amy concord send → no_channel_key); held keys adopt in place, and invite-delivered keys are stored on join. Creating private channels stays open (F7)
S3	01 Deletions	Deleting your own Concord message sends a signed NIP-17 kind 5 to the p-tagged users (leaks the rumor id outside the community) and never reaches the channel	fixed — ChannelChat.delete (examples §2.4: binding + e per target + k per kind) sealed 20013 on the channel plane (ConcordActions.buildChannelDelete); Account.delete/deletePrivately route Concord notes (messages, replies, reactions) to AccountConcordActions.deleteConcordRumors, each target on the plane of its bound epoch (Armada always uses the current plane); tapping an own Concord reaction retracts it the same way
S4	06 §2	Stranded recovery adopts a bundle's newer community_root with no continuity or authority check — a link creator can relocate every member who joined through their link	fixed — ConcordStrandedRecovery only detects (isStranded); the background sweep never moves the base (exposes strandedConcordCommunities); moving forward from a bundle needs the user to re-open the link (joinConcordViaInvite, amy concord recover --rejoin). PR #23's accept-time root gate not implemented (text unavailable; genuine owner editions re-wrap into any plane, so it needs the PR's exact rule)
S5	04 §1	Grant eid never checked against grant_locator(cid, member); a second grant chain at a random coordinate overrides the canonical one, order-dependent	fixed — AuthorityResolver.resolve / ConcordCommunityState.fold / authorizedHeads take the community_id; a Grant edition counts only when its eid == grant_locator(cid, content.member)
S6	04 §4	Banlist unions every fork instead of folding to one head; a ban on a losing fork can never be undone; banlist eid unchecked	fixed — the Banlist folds to ONE authority-gated head at banlist_locator(cid); the rank-delta rule is kept; re-heal = the writer re-applying atop the winner (ConcordModeration.ban again after refold)
S7	04 §1	Equal-version ties break on rumor id only, not authority-first; a low-ranked holder can grind an id to beat the owner	fixed — EditionFold.foldEntityGated/foldGated take an author rank: authority first, then rumor id, both in the head pick (Armada pickHead) and in the walk's anchor/next-link choice. The walk part goes past Armada (whose version.fold walks on rumor id only, so a lower-id fork can strand an edition chained on the owner's sibling) — spec followed
S8	04 §1	Metadata eid not required to equal community_id; a fresh coordinate at a high version bypasses the chain	fixed — metadata is read only at eid == community_id (a fold gate, AuthorityResolver.isWellFormed)
S9	02 §5 / App. B	Seal kind never enforced on read (Control must be 20014, Chat/rekey 20013); any rumor kind from a channel lands in LocalCache	fixed — control: ControlEdition.fromOpened refuses a non-20014 seal; used by the session, ConcordActions.controlEditions (CLI) and Refounding compaction; chat: ChannelChat.acceptOpened requires a 20013 seal, a CHAT_KINDS rumor (9, 1111, 7, 5, 3302, 23311, 1740), the strict binding and a well-formed ms, for stored and typing wraps; EventCache.consumeConcordRumor refuses non-chat kinds too
S10	App. B	NIP-44 65,535-byte plaintext cap not enforced; quartz silently switches to the extended format strict readers reject	fixed — ConcordStreamEnvelope seal/wrap refuse a plaintext over 65,535 UTF-8 bytes (Armada encryptChecked), and open refuses an extended-format payload before decrypting
S11	05 §1	Bundle bounds (channel count, relay cap) not enforced; the join fetches from every relay a bundle names	fixed — ConcordInviteBundle.bound: >256 channels refused, relays de-duplicated + truncated to 5, applied in parse (link bundles) and ConcordDirectInvite.parse; fragments decode ≤3 relays
S12	06 §3	Compaction doesn't abort on an incomplete fold, and republishes the compacted plane before the root roll is confirmed	fixed — compactControlPlane(…, mustCarry) throws IncompleteControlPlaneException on a missing honored head; app sweeps the plane paged (majority of relays DRAINED) and CLI pages it; rekey chunks are publishAndConfirmed first, compaction published only after
S13	02 §9	"Death wins every race": rekey adoption / recovery / refounding don't check for dissolution	fixed — dissolved check in drainConcordRekeys, recoverStrandedConcordCommunities, refoundConcordCommunity, the explicit rejoin, and CLI rekey/recover/refound (ConcordCommands.isDissolved)
S14	05 §2	classify trusts the relay filter: no signature, pubkey == link_signer, or d == "" check; a relay can forge a revocation	fixed — classify(wraps, linkSignerPubKey, token) keeps only events with kind 33301, author == link signer, d == "" and a valid signature (isAtCoordinate); every caller passes the signer

Interop (Armada drops or diverges)

#	Spec	Finding	Status
I1	02 §8	Community List on retired 13302, hex, no fragments, no tombstones	in progress (this branch)
I2	02 §6	Metadata/Channel edits rebuilt from scratch, wiping custom, message_expiration (CORD-08), av_brokers	fixed — ConcordJson.encodePreserving lays every edit over the authorized head; metadata/channel forms start from the folded entity
I3	03 §2	Per-channel voice flag still modeled and rendered (every Channel is callable since 23dcea5)	fixed — field removed (rides through as an unknown key), Mic icon and blank-preview special case removed
I4	04 §1/§5	vac never written or verified — Armada drops every non-owner edition we author	fixed — ConcordModeration stamps every non-owner edition with AuthorityCitations.forActor (own grant coordinate, folded head version + hash); every fold gate (roles, grants, banlist, metadata, channels, unmodeled kinds, floors/compaction) requires it per Armada citationSatisfied
I5	04 §2	Role content lacks role_id; Armada ignores every role we mint	fixed — RoleEntity.roleId written by defineRole; read accepts a legacy role without it, refuses a mismatching one
I6	04 §1	First edition is v0; spec says versions start at 1	fixed — genesis and every new entity start at v1; v0 chains still read
I7	04 §7	Unknown-vsk editions (pins, signals) dropped by our compaction	fixed — a canonical unmodeled vsk parses with entityKind == null + raw vsk; floors and compaction carry its gated head verbatim (11 by PIN_MESSAGES, 12 by MANAGE_CHANNELS, others by any staff bit). vsk 6/7/9/10 are no longer parsed as Control editions
I8	06	Rekey chunk index is 0-based; Armada requires 1-based and drops all our Refoundings	fixed — ConcordRekey.tags takes a 1-based index (require 1..n); chunkOf parses strict decimals and refuses 0 / i > n; receivers drop malformed chunks
I9	06 §3	Rotations carry no vac	fixed — rotations carry vac on every chunk (ConcordRotationAuthority.citationFor, owner none); receivers require ConcordReceive.isHonoredRotation (BAN + citationSatisfied, Armada semantics) in the app drain and CLI rekey; a rotator whose chunks cite different Grants is dropped
I10	06	120 base blobs per chunk can overflow NIP-44; Armada budgets 99 @104 B / 90 @136 B	fixed — ConcordRekey.chunkBlobs budgets the rumor JSON at 40,960 bytes (Armada REKEY_RUMOR_MAX_BYTES) plus the 120 count cap; test pins the seal (wrap plaintext) ≤ 65,535 with 136-byte blobs
I11	05 §3	Invite links carry more than 3 bootstrap relays; Armada's decoder throws	fixed — encodeFragment truncates non-stock lists to 3 (stock set stays a flag); decodeFragment refuses count > 3
I12	06 §3	No race convergence (lowest new root), not idempotent on retry	fixed — findNewRoot converges on the lowest authorized root (accept filter before converge); sessions watch the current epoch's own rekey address and drainConcordRekeys heals down-only (ConcordReceive.withHealedRoot), keeping the losing root as a same-epoch held root (only the lowest per epoch is folded: canonicalHeldRoots); retries reuse reserved keys (ConcordRefounding.reserveKeys; in-memory in the app, persisted in amy's store). Not done: the CLI has no heal step; re-issuing a losing branch's channel keys (no private channels yet, F7)
I13	03 §3	Binding check not strict (duplicates accepted, "04"/"+4" parse)	fixed — exactly one channel and one epoch tag, epoch compared as its canonical decimal string (Armada uniqueTag/checkChannelBinding); builders drop binding tags smuggled in extraTags
I14	03 §2	Channel deletion not terminal across the chain; no 64-byte name cap	fixed — any gated channel edition with deleted:true retires the channel for good (Armada everDeleted); the channel gate refuses an empty or >64-byte name so the fold falls back to the previous candidate, and defineChannel/create/rename refuse to mint one
I15	02 §4	No ms tag on chat rumors	fixed — every ChannelChat rumor carries ["ms", 0..999] after the binding; malformed/duplicated ms drops the rumor; channelMessages and edit recency order by created_at*1000+ms (the shared feed still sorts by created_at; open PR #7 may drop ms)
I16	examples §2.1	Inline quote q tag is 2-element, Armada writes ["q", id, "", author]	fixed — four-element q (the p credit stays, as Armada keeps it). Also CORD-03 §3: your own kind-1111 thread replies can now be edited (kind 3302) like kind-9 messages
I17	04 §2, 02 §6	Caps (role name, roles per member/community, metadata name/description) not enforced	fixed — ConcordLimits; refused on write (factory, ConcordModeration, app verbs, CLI) and enforced at fold like Armada: over-cap role/metadata editions fall back, a Grant's role_ids trim to 64, the Community keeps its 100 lowest role_ids. Also: ev/vac/vsk must be canonical decimals and a duplicate vsk/eid/ev/ep/vac invalidates the edition; CLI knows VIEW_AUDIT_LOG/MENTION_EVERYONE/PIN_MESSAGES; the app's Admin role matches Armada's ADMIN_ALL
I18	05 §1, §4	Join doesn't echo invite attribution; CLI join publishes no Guestbook Join; Invite List merge lets the patch win; malformed tombstones dropped	fixed — join echoes creator_npub/label in the Guestbook Join (mints now set creator_npub); amy concord join publishes a Guestbook Join; Invite List merge is first-wins per token; untyped tombstones carried as opaqueTombstones and still retire their token

Features

#	Spec	Finding	Status
F1	04 §7	Pins	open → pins batch
F2	08	Disappearing Messages (sender tags, reader refusal/hiding/purge, 1740 notice, settings UI)	metadata field + parse fixed; the rest open → chat-plane batch
F3	07	A/V calls: only key derivation, the 27235 grant and 23313 presence builders exist; no broker/SFU client, no media E2EE. Needs a LiveKit client whose license must be checked first	open — out of scope for this pass
F4	07	Broker token has no nonce (same-second requests collide in the broker's replay set); presence fold doesn't take latest-per-author	open → chat-plane batch (quartz only)
F5	05 §5	Invite Registry (vsk 8) not published or folded	open
F6	05 §6	Direct invites: wire format only, no send/receive	open
F7	06 §1-2	Channel-scope rekeys; private-channel keys in invites	open (depends on S2)
F8	06 §2, 02 §8	Walk forward from seed; we still keep intermediate roots in a held_roots List extension the spec says doesn't belong there	open
F9	04 §6	Kick (kind 3309)	open
F10	03	WebXDC (kind 3310)	open

Spec issues to raise upstream

• CORD-06 §1 counts rekey capacity in blobs ("up to 120 participants per event"), but 120 base blobs overflow NIP-44's 65,535-byte plaintext once wrapped; the spec should state the byte budget (Armada uses a 40,960-byte rumor ceiling).
• The rekey blob plaintext is base64-encoded before NIP-44 (signer APIs take strings); unpinned by the spec, as Armada's own comment notes.
• Rekey seal kind (20013) and the chunk indexing base are implied by examples only; worth a MUST.
• 02 §8 and examples §6.2 cite "a dissolution payload (CORD-06 §1)", but CORD-06 defines no such payload, and Armada has none. Dangling reference.
• CORD-07 §2 should require a nonce in the 27235 grant (Armada already adds one): two members requesting in the same second otherwise produce the same event id and collide in the broker's mandatory replay set.