mempalace-toolkit/docs/rfc-001-global-palace.md

RFC 001 — Global palace with local fallback (mempalace-edge)

Status	Draft — design agreed, not implemented
Created	2026-08-08
Applies to	mempalace 3.6.0, mempalace-toolkit @ 96699f2, pi-devbox ≥ v1.3.0
Decision	Phases 0–2 + 4 in scope. Phase 3 (full pull replication) explicitly deferred — "a laptop that can reach its own stuff plus whatever it can reach" is good enough. Centralization is strictly opt-in — solitary devbox operation remains the default and must not change (§1.1).
Recon update	2026-08-09 — §9 Q1 and Q6 are RESOLVED, both in the permissive direction (opencode supports remote MCP; opencode-devbox already templates the mempalace entry). Neither is a blocker. See those entries for evidence; §2, §4.1 and R5 were corrected accordingly.

Read this first if you are asked to "centralize MemPalace" / "sync palaces between machines". Most of the hard-won facts below are non-obvious and two of them are actively destructive if you guess wrong (§7.1, §7.2). The evidence index in §10 lets you re-verify any claim without re-reading 45k lines.

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1. The problem

One palace per machine per harness. Today: a pi-devbox container on EMB-7KJ4VR4G, another on tor-ms22, opencode-devbox containers, MBP-M1-2020, plus native hosts — each with a private ~/.mempalace. Consequences:

1. Memory is sharded by accident of where you happened to be working. A decision recorded on the laptop is invisible to the agent on the desktop.
2. Container recreates are amnesia events unless the palace happens to be host-bind-mounted.
3. The KG is the worst hit — kg_query/kg_timeline answers depend on which machine you ask.

Target state: one primary palace holds the fleet's memory. Every client keeps working when the primary is unreachable (writes buffer locally, reads degrade to local), and reconciles when it returns. Access is authenticated per device, with a sane authorization policy.

1.1 Hard requirement: solitary-first, centralization strictly opt-in

This is a requirement, not a preference, and it constrains every choice below.

Centralization solves a problem specific to this usage pattern: several machines and containers (pi-devbox, opencode-devbox, native hosts) doing development and other work against a common set of artifacts. For most users of the published joakimp/pi-devbox and joakimp/opencode-devbox images it is useless — one machine, one palace, done. Evidence that this is already the norm: all three sampled opencode-devbox deployments (docker-compose-repo/{synlig,nyvaken,devbox-affection}/) contain zero mempalace references.

ID	Requirement
R1	Solitary operation stays the default and stays unchanged. With no MEMPALACE_* variables set, a devbox must behave exactly as it does today: harness → local mempalace-mcp over stdio, palace at ~/.mempalace. No extra process, no outbox, no network calls, no new failure mode, no measurable startup cost.
R2	Opt-in lives in docker-compose.yml + .env — the mechanism users already know. No opt-in via image rebuild, no baked-in defaults, no latest-central variant.
R3	Credentials only in .env (chmod 600, gitignored). Never in docker-compose.yml, never in the image, never on a command line (visible in ps), never logged. Compose passes them through with a ${VAR:-} empty default so solitary users never define them.
R4	No new required services. The primary stays in the separate standalone docker-compose.mempalace.yml project; it is never merged into the main compose file. A solitary docker compose up starts exactly what it starts today.
R5	Degrade, never fail, when mempalace is absent. The published opencode-devbox image does ship mempalace by default (Dockerfile.base:380,402 — ARG INSTALL_MEMPALACE=true, MEMPALACE_VERSION=3.6.0, installed via uv tool install), but it is a build arg precisely so it can be omitted to save ~300 MB — and a bind-mounted host config or a non-devbox client may have no mempalace either. So any wiring must stay additive and skip when the binary is missing — the probe-and-warn idiom install.sh already uses (warn + return 0, never halt).
R6	Reversible. Commenting the .env lines out returns the container to pure solitary operation, with the local palace intact and readable.

Acceptance test for R1 (must pass before Phase 2 ships): bring up a devbox with no MEMPALACE_* variables; assert the palace tool list, drawer counts and diary writes are identical to the previous image, and that no edge/outbox process exists (pgrep -f mempalace-edge → empty).

1.2 The opt-in surface

The existing convention is already the right one — extend it, do not invent a new one. pi-devbox's .env.example lines 12–23 already ship a commented MEMPALACE_REMOTE_URL / MEMPALACE_REMOTE_TOKEN pair under the heading "MemPalace memory (local by default)", and docker-compose.yml:79-83 already ships the devbox-palace volume commented out. So the opt-in ladder becomes three states derived from two variables — both existing behaviours are preserved, the third is new:

MEMPALACE_REMOTE_URL	MEMPALACE_EDGE	Behaviour	Status
unset	—	local stdio mempalace-mcp, palace at ~/.mempalace	default, today, unchanged (R1)
set	unset/0	direct remote HTTP; no local palace, no offline	today (96699f2), unchanged
set	1	mempalace-edge: local-first writes + outbox → primary + merged reads	new (Phase 2)

Volume coupling reverses under edge mode — document it prominently. Today .env.example correctly says that with MEMPALACE_REMOTE_URL set "the devbox-palace volume is then irrelevant", because the remote owns all state. Under edge mode that flips: the local palace holds the outbox and all local-first writes, so an un-persisted palace means losing un-flushed writes on container recreate. Opting into MEMPALACE_EDGE=1 therefore requires uncommenting devbox-palace:/home/developer/.mempalace.

Corollary for §4.1: mempalace-edge must not be in the path unless opted in. Registering it unconditionally (letting it decide by env at runtime) is tempting — one static config for every harness — but it violates R1 by inserting a process and a failure mode into every solitary user's setup. Selection must happen at registration time. See open question §9.6.

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2. Verified starting point (as of 2026-08-08)

Two of the three pieces already exist. This is not greenfield.

Piece	State	Evidence
Primary server	✅ Exists. mempalace serve --host --port --token --tls-cert --tls-key --read-only --allow-insecure. Bearer token compared with hmac.compare_digest, mandatory on non-loopback binds (unless --allow-insecure), TLS 1.2+ resolved before bind, Host-header pinning + Origin allowlist (anti-DNS-rebinding), 16 MiB body cap, token-free /healthz.	cli.py:cmd_serve (~1448); mcp_server.py:5205-5215, 5284-5289
Remote client	⚠️ Exists for pi only, and it is either/or. createClient() picks stdio or HTTP once at process start.	extensions/pi/mempalace.ts:629-641
Fallback + resync	❌ Absent everywhere. On remote failure the pi bridge re-handshakes the same URL, then de-registers all palace tools and runs blind.	extensions/pi/mempalace.ts:665-673
opencode client	✅ Remote is supported and already wired. opencode's published schema (https://opencode.ai/config.json, $defs.McpRemoteConfig) makes {"type":"remote","url","headers","oauth"} a first-class sibling of McpLocalConfig, headers being a free string→string map (so bearer is a convention, not a constraint). opencode-devbox already emits exactly that entry when MEMPALACE_REMOTE_URL is set. The all-type:local configs in myconfigs are a deployment fact, not a capability limit.	generate-config.py:107-118; hook at entrypoint-user.sh:117; schema $defs.McpRemoteConfig
Server compose	✅ Exists: pi-devbox/docker-compose.mempalace.yml (canonical) + a tor-ms22 derivative (docker-compose-repo/tor-ms22/pi-devbox/, df2c2ae, port 8766, uid 1000, binds the real ~/.mempalace). Not enabled.	pi-devbox CHANGELOG v1.3.0 (2026-07-02)

Stale docs warning. docker-compose.mempalace.yml, .env.example and CHANGELOG v1.3.0 all say the HTTP transport is unauthenticated and should be fronted by a reverse proxy. That was true for mempalace-mcp --transport http in the v1.3.0 era. mempalace 3.6.0's serve has token + TLS built in (upstream #1877). Fix those comments during Phase 1. Specifically: pi-devbox/.env.example:21 still advertises mempalace-mcp --transport http --host 0.0.0.0 --port 8765 as the way to serve a shared palace — replace with mempalace serve --token … --tls-cert …, and change the example URL from http://mempalace.lan:8765/mcp to https://.

Two things that sound like the feature and are not

• sync.py is not replication. It is gitignore-aware drawer deletion: "Removes drawers whose source files are now gitignored, deleted, or moved out of the project" (sync.py:1-12). See §7.2 — running it against a shared palace is a fleet-wide memory wipe.
• wal/write_log.jsonl is not a replayable WAL. _WAL_REDACT_KEYS strips content/content_preview/document/entry/entry_preview/query/text and replaces them with "[REDACTED N chars]"; all 12 references are writers, there is no reader and no replay function (wal.py:74). Reconstructing memory from it is information-theoretically impossible.

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3. Why we sync operations, not databases

Row-level / file-level replication of a palace is a trap in this codebase. Four findings, each independently disqualifying:

1. Vectors are not portable. Embeddings are computed client-side — backends/pgvector.py:6-8: "Embeddings are still produced locally by MemPalace through the core embedding wrapper before vectors are written to Postgres." Cross-architecture ONNX determinism (arm64 macOS vs x86-64 Linux, different execution providers) is not guaranteed. → Ship text + metadata, always re-embed on receipt. Cheap and safe: the raw text is always stored as the chroma document.

2. KG rows cannot be copied. triples has no UNIQUE(subject,predicate,object,valid_from) — only id is unique, and make_triple_id embeds datetime.now(). A row copy therefore duplicates every fact. But add_triple() guards at the application level (SELECT id … WHERE subject=? AND predicate=? AND object=? AND valid_to IS NULL → returns the existing id), so replaying kg_add is idempotent for open facts (knowledge_graph.py:163-178, 305-313).

3. Only one write path has deterministic IDs.

   Write path	ID recipe	Same content on 2 hosts → same ID?
   add_drawer / checkpoint	drawer_{wing}_{room}_{sha256(wing|room|content)[:24]}	YES — content-addressed, merges for free
   project/format miner	…sha256(source_file|chunk_index)	NO — absolute path (/Users/joakim/x vs /workspace/x)
   convo miner	…sha256(source_file|extract_mode|chunk_index)	NO — same reason
   diary	diary_{wing}_{YYYYmmdd_HHMMSSffffff}_{sha256(entry)[:12]}	NO (µs timestamp) — but the 12-hex suffix is a usable content dedup key
   KG triple	t_{s}_{p}_{o}_{sha256(valid_from|recorded_at)[:12]}	NO (recorded_at = now())

   (ids.py:56,71 — ID_RECIPE = "v3", length-prefixed delimited hashing.)

4. Batch dedup will not save a naive merge. dedup.py groups by source_file and only compares within a group (cosine < 0.15) → cross-host duplicates with differing paths are never compared. The mechanism that does work is write-time: tool_check_duplicate(content, threshold=0.9) queries the whole collection, and mempalace_checkpoint already runs it per item.

Conclusion: the MCP tool surface is already a small, coarse-grained, mostly-idempotent operation vocabulary. Log the intent, replay the intent. That sidesteps chroma internals, chunking, embedder drift and vector portability in one move.

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4. Design: mempalace-edge, a local MCP proxy

4.1 Shape

Do not put fallback logic in extensions/pi/mempalace.ts — opencode would need it again, and it may not support remote MCP at all (§9.1). Instead: a sidecar that is an MCP server.

pi        (mempalace.ts, stdio) ─┐
opencode  (mcp: type=local)     ─┼──►  mempalace-edge  ──HTTPS MCP──►   PRIMARY
mempalace CLI (local palace)    ─┘        │   (stdio MCP server)       mempalace serve
                                          ├─ child: mempalace-mcp       --token --tls-cert
                                          │  (local palace, always writable)
                                          └─ outbox.sqlite (durable op queue)

mempalace-edge needs zero mempalace internals — it is an MCP-to-MCP proxy. It speaks stdio down to a child mempalace-mcp and HTTPS up to the primary, reusing the RemoteMcpClient already written in 96699f2 (extensions/pi/mempalace.ts:390, vendored from pi-extensions/mcp-loader.ts — mind the MCP-STREAMABLE-HTTP-CLIENT-SYNC: v1 drift token if you copy it again).

Why this shape wins:

• One implementation for every harness. opencode's change is one line: "command": ["mempalace-edge"]. pi's is one line. The CLI is untouched.
• Tools never vanish from the tool list, so wake-up context injection keeps working offline — unlike today's fail-soft de-registration.
• Survives mempalace upgrades: coupled to the tool schema, not to chroma/HNSW.
• The remote transport is sessionless JSON-RPC today (per 96699f2's own note), so reconnect after an outage is cheap — there is no session to re-establish.

But per R1, that one-line change is conditional, not baked in. The edge binary is present in the image (it costs nothing unused) and inserted into the path only when MEMPALACE_EDGE=1:

• pi: createClient() (extensions/pi/mempalace.ts:629) already branches on env at startup — add a third branch. Zero change to the default path.

• opencode: the MCP server entry is static JSON — but the templating step already exists and already implements the first two rungs of the §1.2 ladder. rootfs/usr/local/lib/opencode-devbox/generate-config.py (run unconditionally from entrypoint-user.sh:117) registers mempalace as {"type":"remote", url, headers:{Authorization: Bearer …}} when MEMPALACE_REMOTE_URL is set, else {"type":"local","command":["mempalace-mcp"]} when the binary is on PATH, else nothing — R5-compliant already. Its own comment states it uses the "same env contract as the mempalace.ts pi extension … so one shared MemPalace can serve pi + opencode + native", i.e. the two images are deliberately kept in step. Phase 2's opencode work is therefore a third branch in an existing script, not a new mechanism.

  ⚠️ But the opt-in does not propagate to an existing container. generate-config.py never overwrites an existing config, and ~/.config/opencode is the named volume devbox-opencode-config (docker-compose.yml:64,153) — so a config generated during solitary use survives recreate, and later setting MEMPALACE_REMOTE_URL/MEMPALACE_EDGE only produces a non-loaded opencode.jsonc.proposed sidecar for manual merge (generate-config.py:203-244). Flipping the .env alone is a no-op there. Phase 1/2 docs must say: merge the sidecar, or docker volume rm the config volume, to adopt the change — and the same applies in reverse for R6 (reversibility). This asymmetry with pi — whose createClient() re-reads env every start — is the single biggest behavioural difference between the two harnesses under this RFC.

4.2 Routing policy

service.py:29,54,72 already ships the exact three-way split we need — READ_TOOLS, WRITE_TOOLS, MAINTENANCE_TOOLS ({mine, sync, reconnect}) — plus classify_tool().

Class	Primary up	Primary down
read (search, kg_query, diary_read, list_*, traverse…)	query both, merge ranked lists, dedupe by drawer id	local only, response flagged degraded: true
write (add_drawer, checkpoint, diary_write, kg_add…)	apply local and enqueue → primary	apply local, enqueue, keep working
maintenance (mine, sync, reconnect)	never proxied — local only (§5, §7.2)	local only
destructive (delete_drawer, delete_by_source, delete_tunnel…)	admin-scoped only; tombstone, never hard-delete remotely	local only

⚠️ classify_tool() must be treated as fail-closed. mempalace_kg_supersede is a real MCP tool (3 references in mcp_server.py) but is absent from WRITE_TOOLS → classify_tool() returns "unknown" for it. An edge proxy that routed "unknown" as read would silently drop supersede operations. Maintain our own tool→class table, default unknown ⇒ write, and file the upstream fix.

The merged-read trick is what makes Phase 3 optional. Both palaces return ranked results with distances; if the embedder identity matches (§7.4) the distances are comparable, so a union + re-sort + dedupe-by-id gives a correct combined result set. You get fleet-wide recall without replicating anything. Offline you simply see less.

KG reads are the exception: unioning triples is unsafe because invalidate/supersede are order-dependent. Use primary-first, local-fallback (no union) for kg_* reads, and accept that an offline KG answer is incomplete.

4.3 Outbox

Model it on daemon.py, which already implements a durable local job queue and is the closest existing prior art (token auth via ensure_token, 0600, per-palace state dir, MAX_ATTEMPTS = 3, recover_running, JOB_RETENTION_DAYS = 7). Its key primitive is worth copying verbatim:

CREATE UNIQUE INDEX IF NOT EXISTS idx_jobs_dedupe_active
  ON jobs(dedupe_key) WHERE state IN ('queued', 'running');

A TOCTOU-safe, cross-process "at most one active job per key". Our outbox rows:

Column	Purpose
op_id	sha256(origin_device, local_seq, tool_name, canonical_payload) — stable across retries, the primary's idempotency key
local_seq	Per-device monotonic counter → causal order for kg_invalidate/supersede replay
origin_device, origin_label	Provenance, stamped by edge (interim) or the primary (authoritative) — never by the agent (§7.3)
tool_name, payload_json	The MCP call to replay
state, attempts, created_at, flushed_at, error_json	Retry/audit

Flush = drain in local_seq order, stop on first hard failure (preserve ordering), exponential backoff, resume on reconnect. The primary de-dupes on op_id; add_drawer's own pre-write probe and add_triple's open-fact guard make replay safe even if op_id tracking is lost.

write_routing.py is the upstream-shaped seam for this if we ever want it in core: its WriteRoutingPolicy{DIRECT,PREFER,REQUIRE} → WriteRoutingTarget{DIRECT,DAEMON,BLOCKED} enums would gain a REMOTE target. The module says it "changes no caller defaults by itself" — i.e. it exists precisely to be extended.

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5. Not everything should be global

Per-wing replication policy, declared in edge config:

Policy	Wings	Rationale
replicated	diaries, wing_pi, checkpoints, KG, hand-authored notes	Small, curated, content-addressed → already merge-safe
local	mined code/docs (e.g. the 13,597-drawer workspace wing on this host)	Derived data, re-mineable from git, and carries exactly the path-dependent IDs that break merging (§3.3)

This shrinks the hard problem to the layer that is already safe, and it is why mine must never be remote: the primary serializes every request behind one lock (§7.5), so a bulk remote mine would stall every other agent in the fleet.

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6. Security model

The transport is largely solved; the gap is authorization, not cryptography.

6.1 Threats, in priority order

1. Memory poisoning / persistent cross-machine prompt injection — the underrated one. Palace content is injected into agent context at wake-up. A shared palace means one careless or compromised container can plant instructions that every other agent in the fleet reads as trusted memory. Mitigation: server-stamped provenance on every synced record (§7.3.2), don't auto-inject wake-up content authored by devices outside a trusted set, keep an admin-only wing for anything instruction-shaped.
2. Aggregation raises exfiltration impact. One primary holds every machine's diaries — which already quote internal hostnames, paths and token prefixes. Mitigation: per-wing ACL; don't put secrets in memory (the WAL redaction list exists for a reason); private-network-only exposure.
3. Accidental mass deletion by a client (sync, delete_by_source) — see §7.2.
4. Availability: the server is single-writer by design; one long operation blocks everyone.

6.2 Policy

Control	Decision
Network posture	Primary never internet-exposed. Bind loopback in the container; publish only onto the private overlay / existing tunnel (Pangolin/newt).
Transport	TLS via serve --tls-cert/--tls-key, or terminate TLS + mTLS in the reverse proxy (cheaper than patching Python's TLS surface).
Authentication	Per-device bearer tokens, not the one shared token. Server-side registry token → {device_id, scopes}. Store in the existing .env.age flow, 0600 on disk. Enables revoking one laptop and rotating without a fleet outage.
Authorization	Per-device read/write wing globs. Server-side refusal of mine/sync/delete_* except for an admin device. --read-only gives a free observer tier.
Provenance/audit	origin_device (+ optional origin_label) + op_id on every record, stamped server-side from the authenticated credential — a client-asserted origin is a hint, not a fact (§7.3.2); server-side append-only op log.
Recovery	Deletes as tombstones; server-side backups with backups.py retention (MEMPALACE_MAX_BACKUPS).
DoS	Keep the 16 MiB cap; add rate limiting; no remote mine.

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7. Landmines — Phase 0 runbook

Do these before any cutover. 7.1 and 7.2 cause silent data loss.

7.1 MEMPALACE_PALACE_PATH ≠ --palace (silent empty KG)

# mcp_server.py:708-711  (_palace_flag_given = bool(_args.palace), line 325)
def _resolve_kg_path() -> str:
    if _palace_flag_given:
        return os.path.join(_config.palace_path, "knowledge_graph.sqlite3")
    return DEFAULT_KG_PATH        # knowledge_graph.py:49 → ~/.mempalace/knowledge_graph.sqlite3

cmd_serve always passes --palace. So the moment you start the server, the KG becomes <palace>/knowledge_graph.sqlite3 — a different file from the live ~/.mempalace/knowledge_graph.sqlite3. The vector store looks fine and the knowledge graph is silently empty.

Four stores, three location rules:

Store	Location rule
drawers	backend-abstracted (BaseCollection)
knowledge_graph.sqlite3	HOME-anchored unless --palace flag (knowledge_graph.py:49)
hallways.json	derived from palace_path, with legacy HOME fallback (hallways.py:73,83)
known_entities.json	HOME-anchored (miner.py:701)

Action: mv all three files into the palace directory before first serve, and verify kg_stats is non-empty afterwards. Corollary: a shared pgvector/qdrant backend shares drawers and nothing else — it would leave the KG as fragmented as it is today. That is why the shared-backend option is not the answer.

7.2 Never run mempalace sync against a shared palace

It classifies drawers whose source files are absent on the running host as orphans and deletes them; _auto_detect_project_roots guesses roots from drawer metadata, so the blast radius is data-dependent rather than obvious. From a laptop that lacks the repos, it is a fleet-wide wipe. Action: edge blocks mempalace_sync from ever reaching the primary; document it; consider an upstream --refuse-shared guard.

7.3 Provenance belongs to the sync boundary — not to the agent, and not to a solitary container

Today every drawer carries exactly {wing, room, source_file, added_by, filed_at, id_recipe} (+chunk_index, parent_drawer_id); diaries add {hall, topic, type, agent, date}. added_by/agent is the agent name (pi, mcp, checkpoint) — never the machine. So in a merged store you cannot tell which host wrote a record, cannot audit, and cannot compute per-device high-water marks.

Earlier drafts of this section said "stamp it everywhere, now, because it cannot be backfilled." That was wrong on both counts. See §7.3.3.

7.3.1 What can actually be stamped (mechanics)

The metadata schema is fixed — there is no free-form field — and tools/call whitelists arguments to declared schema properties (mcp_server.py:4777, "Prevents callers from spoofing internal params like added_by/source_file"), so an extra origin_host=… is silently dropped, not rejected.

Surface	Provenance slot	Notes
add_drawer, checkpoint	added_by	The only one. Free-form (strip_lone_surrogates only, not sanitize_name, so / and @ are legal).
diary_write	none usable	⚠️ Never put a device in agent_name: :3504 does wing = f"wing_{agent_name}" → a separate wing per host, and diary_read filters {"agent": agent_name} (:3636) → diary_read("pi") then misses those entries.
kg_add	none	Only source_file/source_closet/source_drawer_id. Origin is inferable only via source_drawer_id → that drawer's added_by.

added_by is also write-only today: absent from tool_search results, surfacing only via get_drawer → _drawer_payload metadata. → Upstream asks: surface added_by in search results, and give kg_add a provenance field.

7.3.2 Who should stamp it — a ladder of trust

Provenance answers "which device asserted this?" Only something that can verify the answer should write it. Ranked by trustworthiness:

Stamper	Knows the device?	Verifiable?	Uniform?	Verdict
Agent (via skill)	No — must shell out to read env	No	No — per-call boilerplate, forgettable, improvisable	❌ Worst possible place. Rejected.
Client / mempalace-edge	Yes, from host-supplied .env	No — self-asserted	Yes — one line in a proxy	⚠️ Acceptable interim
Primary, from the authenticated credential	Yes	Yes — bound to the token	Yes, for every synced record	✅ Correct home

The decisive point: a client-asserted origin is a hint, not a fact. The primary is the only party that can bind a write to an identity it verified. And under the §4 design every write reaches the primary through an authenticated channel — including offline ones, at outbox-flush time — so the server can stamp the complete set without any client cooperation. Provenance is a property of the sync channel, not of the record's author.

Blocker for the ✅ row, verified in 3.6.0: serve takes a single shared bearer token (srv.auth_token, hmac.compare_digest, mcp_server.py:5291-5293) and the package contains zero occurrences of any device/origin concept. Server-side stamping therefore requires the per-device credentials of §6 — i.e. Phase 4, not Phase 1. Hence the phasing:

• Phase 2 (edge): edge may stamp added_by from its configured env — self-asserted, advisory only, never load-bearing for authorization or destructive scoping.
• Phase 4 (authz): per-device tokens land; the primary stamps authoritatively and the client-supplied value becomes redundant (and must be treated as untrusted input, not merely ignored).

7.3.3 Solitary containers should stamp nothing — and lose nothing by it

A pi-devbox or opencode-devbox running solitarily is a single-origin store by definition. Origin is therefore a property of the whole palace, not of each record — so it can be assigned wholesale at the moment the store stops being solitary: one --origin-device flag on the import/first-sync path attributes every record from that palace to that device.

That dissolves the "impossible to backfill" argument. Per-record stamping is only necessary once records from multiple origins are interleaved in one store, which is exactly and only the primary. So:

• Solitary devboxes: no stamping, no config, no skill instruction, no behaviour change. This is strictly more compliant with R1 than the earlier draft, which quietly asked every solitary user to carry metadata for a feature they had opted out of.
• Migration is unaffected: bulk attribution at import is more reliable than per-record stamping, because it cannot be partially applied.
• Multi-harness on one host stays solved by added_by = agent name (pi vs opencode) — that is what the field is for, and it needs no device component.
• A palace on a shared host bind-mount (as tor-ms22's compose does) is still single-device under the "host owns the palace" model, so it too imports as one origin.

The one case bulk attribution cannot fix: a palace that was already merged from several devices without stamps. Preventing that is precisely why the primary must stamp from day one of Phase 4 — it is the only store where interleaving occurs.

7.3.4 Identity fields, when a stamper does exist

For the edge (interim) and the primary (authoritative) — never for agents:

Field	Source	Rule
origin_device	uuidgen once, stored in the host's .env; later, issued with the device's token	Opaque, stable, collision-free by construction. Compared, never parsed.
origin_label	hostname, same .env	Human readability only. Never identity, uniqueness or scoping. Free to change. Optional — a hostname can leak an asset tag or username (EMB-7KJ4VR4G, HOST_SSH_USER=ECSJPER).

Why not the obvious sources: a container cannot discover its host's identity. hostname returns the container ID (f3bf2a103473) which changes on every recreate; there is no /etc/machine-id; and a baked one would be worse — identical for every container from the same image, a guaranteed collision. Hostnames are also neither unique nor stable (localhost, ubuntu, golden images, two MacBook-Pro.local), and the worse failure is not collision but rename, which silently splits one device's history in two. Hence host-supplied via .env (matching R2/R3 and the existing HOST_SSH_USER / DEVBOX_HOST_ALIAS precedent), not container-derived. Do not persist the id container-side: ~/.mempalace/device_id does not survive recreate for solitary users because devbox-palace is commented out by default (§1.2). And don't write ${HOSTNAME} in compose — bash sets but does not export it, so interpolation sees empty.

Encoding, always three segments so arity is unambiguous:

added_by = "<agent>/<label>/<device>"     e.g.  pi/tor-ms22/7f3a9c2e1b04
                                                pi/-/7f3a9c2e1b04   (label withheld)

The / is the discriminator. A value with no / (mcp, pi, checkpoint) means origin unknown — correct for the ~13.6k drawers already filed, and for every solitary palace forever.

7.3.5 Fail-closed rule for any stamper

If origin_device is unset, blank or unreadable: write no added_by override at all and let the default (mcp / checkpoint / agent name) stand. Never synthesize one. The tempting substitutes are all actively harmful, because each is confidently wrong where absence is honestly unknown:

Substitute	Damage
container hostname / ID	A new fake device per recreate — thousands of singleton identities, each looking legitimate
unknown, localhost, devbox, docker, $USER	Collides across every machine — indistinguishable from one real shared device
a guess from context	Unfalsifiable later

If origin_label alone is missing, use the literal -. If origin_device is missing, do not stamp even when the label is present — a hostname alone is exactly the colliding, mutable identity rejected above.

Note for future agents reading this RFC out of the palace: these notes are themselves a poisoning vector. Do not start hand-stamping added_by because you read this section. Provenance is client and server infrastructure; an agent's contribution to it is to leave the field alone. The mempalace skill carries a one-line guard to that effect.

7.4 Embedder identity is client-local and currently toothless

check_embedder_identity() raises DimensionMismatchError / EmbedderIdentityMismatchError, but the sidecar on this host reads {"mempalace_drawers": {"model_name": "minilm", "dimension": 0}} — and dimension: 0 means unknown and is skipped, so only the model name is compared. The sidecar lives in the client's palace dir (_sidecar.py), so with a remote backend the check is per-client and never centrally enforced. Action: the primary must reject writes from a client whose embedder identity does not match, and merged reads (§4.2) must be disabled on mismatch — comparing distances across models silently degrades recall.

7.5 Concurrency expectations

• _HTTP_REQUEST_LOCK = threading.Lock() wraps every dispatch (mcp_server.py:5115, held at 5346/5513), commented: "HTTP gives us a safer transport, not concurrent Chroma/HNSW mutation." The primary is a single-writer, one-request-at-a-time service. Size for a handful of agents.
• mine_palace_lock uses fcntl.flock(LOCK_EX|LOCK_NB) and exists because parallel HNSW inserts "can corrupt the HNSW graph" — but the lock file is HOME-derived (~/.mempalace/locks/ mine_palace_{sha256(realpath(palace))[:16]}.lock) while the key is palace-derived. Two containers with different ~/.mempalace mounts but the same palace path compute the same key on different files → no mutual exclusion.
• Therefore: reject "put the palace on a NAS/SMB share and point everyone at it." flock over NFS/SMB is unreliable, and the lock wouldn't be shared anyway. One process owning the files and serving HTTP is the supported model — which is exactly why serve exists.

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8. Phasing

Phase	Effort	Deliverable
0 — hygiene	hours	§7 runbook: move KG/hallways/entities, ban sync on shared palaces, fix stale "unauthenticated" docs (incl. pi-devbox/.env.example:21). No provenance work here — it is not backfill-critical (§7.3.3) and belongs to the stamper, not the agent
1 — primary up	hours, no code	mempalace serve --token --tls-cert on a private-net host (reuse docker-compose.mempalace.yml — keep it a separate standalone project, R4 — and mind port 8765 vs pi-studio; tor-ms22 already moved to 8766). Repoint pi clients via MEMPALACE_REMOTE_URL/MEMPALACE_REMOTE_TOKEN. opencode clients can be repointed in the same breath — remote MCP is supported and generate-config.py already emits it (§9.1, §9.6), subject to the sidecar caveat in §4.1. Shared memory today, no offline.
2 — mempalace-edge	~1 week	The actual ask: local-first writes + outbox flush + merged reads + per-wing policy. Not "fixes opencode" — opencode's transport is already fine after Phase 1; what edge adds there is offline/local-first, since generate-config.py's switch is remote or local with no failover. Ships with the §1.2 opt-in wiring (compose + .env.example + a third branch in the existing generate-config.py) and must pass the R1 acceptance test.
3 — pull replication	~1 week	DEFERRED (2026-08-08). Server-side op-log with monotonic seq → each edge a full offline replica. Only needed if a laptop must hold everything offline. Accepted trade-off: offline recall = own writes + last-reachable state.
4 — authz	days	Per-wing ACL, per-device scopes, audit log, token rotation

Phase 1 is worth doing on its own — it is pure configuration and immediately ends KG fragmentation for online clients.

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9. Open questions

1. Does opencode's MCP config support a remote/HTTP transport at all? RESOLVED 2026-08-09: YES. opencode's published JSON Schema (https://opencode.ai/config.json) defines $defs.McpRemoteConfig = {type:"remote" (enum), url (required), headers?: {string:string}, oauth?, enabled?, timeout?} as a sibling of McpLocalConfig inside Config.properties.mcp.additionalProperties.anyOf. So headers carries any bearer/API-key scheme, and set oauth: false to stop opencode probing the URL for OAuth. The earlier "every sampled entry is type:local" observation was deployment evidence being read as schema evidence — the schema settles it in one fetch. Consequence: the edge proxy is not the only option for opencode. A plain Phase 1 mempalace serve --token can be consumed directly, so nothing in the phasing depends on this question any more. What opencode still lacks is local-first writes and offline fallback — generate-config.py's switch is remote or local per container, with no failover — and that is the real Phase 2 justification for it.
2. Upstream or local? mempalace-edge needs no core changes, so it belongs in this repo (bin/ + extensions/). But origin_device stamping from the authenticated token, per-wing ACL, the kg_supersede classification fix, and a sync --refuse-shared guard all want to go upstream (github.com/MemPalace/mempalace).
3. Chunked drawers under merge. Oversized content splits into {drawer_id}_chunk_NNNNNN with parent_drawer_id, and the add-time idempotency probe checks only the last chunk id — a partially transferred chunk set may look "already present" and stay truncated. Unverified; test before trusting bulk replay.
4. migrate.py as a bootstrap tool. extract_drawers_from_sqlite() reads {id, document, metadata} straight out of chroma's SQLite (bypassing the chromadb API) and re-adds them with ids and metadata preserved and embeddings recomputed (migrate.py:326) — the right shape for a one-shot "seed the primary from an existing palace". Unverified: col.add behaviour on id collision into a non-empty target. Test before relying on it. (exporter.py is markdown-only, lossy, and has zero callers — not a transfer format. backups.py is retention pruning only.)
5. Does _HTTP_REQUEST_LOCK stay held for the duration of an MCP-triggered mine? Strongly suggested by the code shape; if yes, a remote mine makes the primary unusable for its duration (another argument for §5).
6. How does opencode-devbox learn the opt-in? RESOLVED 2026-08-09: it already does. The image ships rootfs/usr/local/lib/opencode-devbox/generate-config.py, invoked from entrypoint-user.sh:117 on every start, which auto-registers the mempalace MCP server — remote+bearer when MEMPALACE_REMOTE_URL/MEMPALACE_REMOTE_TOKEN are set, local stdio when mempalace-mcp is on PATH, nothing otherwise — documented in that repo's .env.example:38-49 and .env.shared.example:30-35. It also ships mempalace by default (see R5). So the config is templated at container start, not baked, and Phase 2 only adds a third branch. Two residual constraints replace the original unknown, and both are documented in §4.1: (a) the script never overwrites an existing config and ~/.config/opencode is a named volume, so an env flip yields only an opencode.jsonc.proposed sidecar — adopting or reverting the opt-in needs a manual merge or a volume removal; (b) it no-ops entirely unless OPENCODE_PROVIDER is set. Prefer extending this script over inventing a parallel mechanism — treat it as the reference implementation, and check it before designing any pi-devbox-side mechanism with an opencode counterpart.

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10. Evidence index

Re-verify without re-reading the package. Paths relative to /opt/uv-tools/mempalace/lib/python3.13/site-packages/mempalace/ (mempalace 3.6.0) unless noted.

Claim	Where
Server auth/TLS/read-only	cli.py:1448-1503; mcp_server.py:282-320, 5205-5215, 5284-5289
Single global request lock	mcp_server.py:5115, 5346, 5513
KG path follows --palace flag only	mcp_server.py:325, 708-711; knowledge_graph.py:49
KG DDL, no (s,p,o) uniqueness, open-fact guard	knowledge_graph.py:163-178, 305-313
ID recipes	ids.py:25, 56, 71; diary at mcp_server.py:3511-3514
Tool classification (+ kg_supersede gap)	service.py:29, 54, 72-84
Write-routing seam	write_routing.py:1-60
Outbox prior art (queue DDL, token, retries)	daemon.py (_init_db, ensure_token, MAX_ATTEMPTS)
sync is destructive pruning	sync.py:1-12
WAL redacts + has no reader	wal.py:74, _WAL_REDACT_KEYS
Client-side embeddings	backends/pgvector.py:6-8; embedding.py:6-11; _sidecar.py
Dedup scoped by source_file	dedup.py:get_source_groups
Store location rules	hallways.py:73,83; miner.py:701
Mine lock (HOME-derived file)	palace.py:1090, 1123-1128
Migrate as export primitive	migrate.py:extract_drawers_from_sqlite, :326
pi remote transport + fail-soft	mempalace-toolkit/extensions/pi/mempalace.ts:11-12, 87, 108, 390, 629-641, 665-673 (commit 96699f2)
Server compose + port history	pi-devbox/docker-compose.mempalace.yml; pi-devbox/CHANGELOG.md v1.3.0; docker-compose-repo/tor-ms22/pi-devbox/ (df2c2ae)
Existing opt-in convention (§1.2)	pi-devbox/.env.example:12-23 ("MemPalace memory (local by default)", commented MEMPALACE_REMOTE_URL/_TOKEN); pi-devbox/docker-compose.yml:79-83 (devbox-palace volume commented out)
opencode-devbox does not wire mempalace	docker-compose-repo/{synlig,nyvaken,devbox-affection}/opencode-devbox/docker-compose.yml — zero mempalace references in any

11. See also

• ARCHITECTURE.md — producer side (how the palace gets fed); §6 upstream roadmap
• extensions/pi/README.md — pi bridge internals
• SKILL.md — consumer-side protocol (search before answering, diary before exit)