swarm: Rule 4 — engram-write is @manager-ONLY, enforced by capability

New hard invariant (Will): only the orchestrator mutates global engram state;
workers are read-only against the full engram + write only their own local
geometry. This is an AUTHORITY gate (capability), not a health gate — a worker
is STRUCTURALLY UNABLE to mutate global engram state regardless of engram health.

- containment.el: scope tokens now carry a caps set. Orchestrator token holds
  engram:write + dharma:emit (@manager-only, the VBD rule that only the manager
  mutates global state); worker token holds ONLY engram:read. Rule 4:
  containment_check_engram_write / _dharma_emit reject any caller lacking the
  capability — same scope-token mechanism as the live Rule-2 denial.
- swarm.el: swarm_engram_write is the ONLY engram write path, gated by Rule 4;
  a worker token is denied before any HTTP is issued (no mutation). The curated
  merge (commit=1) is the sole writer: the orchestrator commits approved
  geometry via its write-capable token. Workers' full-engram READ stays intact.
- reshape_surface.el: compose op_write (json_escape_string) for the commit path.
- harness: Rule-4 suite proven — worker engram-write DENIED by capability, no
  node created, violation journalled; orchestrator passes the gate as sole
  writer. 24/24 green on the :8901 clone with real cognition.

Authority gate holds independent of daemon write-health (proven with daemon
both alive and, earlier, crashed). Prod :8742 untouched.

lang/swarm/containment.el

@@ -21,8 +21,19 @@
 
 // ── Token minting ────────────────────────────────────────────────────────────
 
-// containment_coordinator_token — the token a coordinator holds. Depth 0.
-// Only a coordinator token may open a swarm.
+// CAPABILITIES. A scope token carries a `caps` set — the authority it holds.
+// This is an AUTHORITY gate, not a health gate: capability is decided at mint
+// time and cannot be acquired at runtime. Engram-WRITE (op_write/op_relate/
+// op_supersede -> POST /api/nodes, /api/edges, DELETE) and dharma_emit are
+// @manager-ONLY capabilities — exactly the VBD rule that only the orchestrator
+// mutates global state. The orchestrator's token carries them; a worker's token
+// NEVER does. A worker is therefore STRUCTURALLY UNABLE to mutate global engram
+// state, regardless of engram health.
+fn cap_orchestrator() -> String { return "engram:read,engram:write,dharma:emit,state:write" }
+fn cap_worker() -> String { return "engram:read" }
+
+// containment_coordinator_token — the token the orchestrator (@manager) holds.
+// Depth 0. Carries the engram-WRITE + dharma-emit capabilities (@manager-only).
 fn containment_coordinator_token(corr_id: String) -> String {
     let kv: [String] = el_list_empty()
     let kv = el_list_append(kv, "kind")
@@ -33,11 +44,15 @@ fn containment_coordinator_token(corr_id: String) -> String {
     let kv = el_list_append(kv, "")
     let kv = el_list_append(kv, "depth")
     let kv = el_list_append(kv, "0")
+    let kv = el_list_append(kv, "caps")
+    let kv = el_list_append(kv, cap_orchestrator())
     return json_build_object(kv)
 }
 
 // containment_worker_token — the token stamped into a worker's envelope. Depth 1.
-// A worker token is a closed boundary: holding it forbids opening/joining swarms.
+// A closed boundary: forbids opening/joining swarms AND carries ONLY the
+// engram:READ capability — no engram:write, no dharma:emit. Read-only against the
+// full engram; may write only its own local geometry (its returned result).
 fn containment_worker_token(corr_id: String, worker_id: String) -> String {
     let kv: [String] = el_list_empty()
     let kv = el_list_append(kv, "kind")
@@ -48,9 +63,16 @@ fn containment_worker_token(corr_id: String, worker_id: String) -> String {
     let kv = el_list_append(kv, worker_id)
     let kv = el_list_append(kv, "depth")
     let kv = el_list_append(kv, "1")
+    let kv = el_list_append(kv, "caps")
+    let kv = el_list_append(kv, cap_worker())
     return json_build_object(kv)
 }
 
+// containment_has_cap — does this token carry capability `cap`?
+fn containment_has_cap(token: String, cap: String) -> Bool {
+    return str_contains(json_get_string(token, "caps"), cap)
+}
+
 // ── Rule checks (return "" on allow, or a rejection reason string) ───────────
 
 // containment_check_open — may the holder of `token` OPEN a new swarm?
@@ -97,6 +119,28 @@ fn containment_check_lateral(from_token: String, to_worker_id: String) -> String
     return ""
 }
 
+// containment_check_engram_write — RULE 4: only a token carrying the
+// engram:write capability (the orchestrator's) may mutate global engram state.
+// A worker token (engram:read only) is REJECTED — the authority gate. Reuses the
+// exact scope-token mechanism as Rule 2's open-denial. Returns "" on allow, or a
+// rejection reason. This is an AUTHORITY gate: it does not consult engram health.
+fn containment_check_engram_write(token: String, op: String) -> String {
+    if containment_has_cap(token, "engram:write") {
+        return ""
+    }
+    return "CONTAINMENT rule 4: engram-write is @manager-only — a worker is read-only against the engram and may not mutate global state (op=" + op + " kind=" + json_get_string(token, "kind") + " worker=" + json_get_string(token, "worker") + " caps=" + json_get_string(token, "caps") + ")"
+}
+
+// containment_check_dharma_emit — the same @manager-only rule for dharma_emit,
+// grounding Rule 4 in VBD: global-state mutations (engram-write, dharma-emit) are
+// orchestrator-only, checked by the one capability mechanism.
+fn containment_check_dharma_emit(token: String) -> String {
+    if containment_has_cap(token, "dharma:emit") {
+        return ""
+    }
+    return "CONTAINMENT rule 4: dharma_emit is @manager-only (kind=" + json_get_string(token, "kind") + ")"
+}
+
 // ── Enforcement helpers ──────────────────────────────────────────────────────
 
 // containment_allows_open — Bool convenience over containment_check_open.
@@ -121,3 +165,17 @@ fn containment_guard_open(token: String, corr_id: String) -> String {
     worktrack_append("containment.violation", corr_id, "open", p)
     return reason
 }
+
+// containment_guard_engram_write — assert a token may mutate global engram state
+// (Rule 4). Returns "" if allowed; otherwise journals a containment.violation and
+// returns the reason. The write path MUST abort on a non-empty return.
+fn containment_guard_engram_write(token: String, corr_id: String, op: String) -> String {
+    let reason: String = containment_check_engram_write(token, op)
+    if str_eq(reason, "") {
+        return ""
+    }
+    let p0: String = json_set_str("{}", "reason", reason)
+    let p1: String = json_set_str(p0, "op", op)
+    worktrack_append("containment.violation", corr_id, "engram-write", p1)
+    return reason
+}

lang/swarm/reshape_surface.el

@@ -64,6 +64,34 @@ fn op_attend(node: String, observer: String) -> String {
     return http_post_json(engram_url() + "/api/attend", body)
 }
 
+fn identity_typed(t: String) -> Bool {
+    if str_eq(t, "self") { return true }
+    if str_eq(t, "values") { return true }
+    return false
+}
+fn type_to_node_type(t: String) -> String {
+    if str_eq(t, "knowledge") { return "Knowledge" }
+    if str_eq(t, "artifact") { return "Artifact" }
+    if str_eq(t, "backlog") { return "WorkItem" }
+    if str_eq(t, "process") { return "Process" }
+    if str_eq(t, "state") { return "InternalStateEvent" }
+    return "Memory"
+}
+
+// write — add a node (POST /api/nodes). Identity types refused. This is a
+// global-engram MUTATION — @manager-only (Rule 4); never called on a worker path.
+// (Reshape's op_write, with json_escape -> the available json_escape_string.)
+fn op_write(content: String, typ: String, importance: Float) -> String {
+    if str_eq(content, "") { return "{\"error\":\"write: content required\"}" }
+    if identity_typed(typ) {
+        return "{\"error\":\"write type=" + typ + " is write-protected -> intentional-cultivation\"}"
+    }
+    let body: String = "{\"_auth\":\"" + engram_key() + "\",\"content\":\"" + json_escape_string(content)
+        + "\",\"node_type\":\"" + type_to_node_type(typ) + "\",\"tier\":\"Working\",\"importance\":"
+        + float_to_str(importance) + "}"
+    return http_post_json(engram_url() + "/api/nodes", body)
+}
+
 // learn — the reflexive correspondence-beat: calibrate the steering-prior.
 // (POST — needs a write-healthy clone.)
 fn op_learn(seeds: String, faculty: String) -> String {

lang/swarm/swarm.el

@@ -300,6 +300,28 @@ fn swarm_converge(strategy: String, results: [String]) -> String {
     return swarm_converge_collect(results)
 }
 
+// ── the ONLY global-engram write path (Rule 4, @manager-only) ────────────────
+//
+// Every engram mutation flows through here and is gated by the caller's token
+// capability. Only the orchestrator's token carries engram:write, so a worker
+// (engram:read only) calling this is DENIED by capability before any HTTP is
+// issued — structurally unable to mutate global engram state, regardless of
+// engram health. This is the curated-merge write: the orchestrator committing
+// the geometry it approved. Workers never reach a successful branch here.
+fn swarm_engram_write(token: String, corr_id: String, content: String, typ: String, importance: Float) -> String {
+    let deny: String = containment_guard_engram_write(token, corr_id, "engram.write")
+    if str_eq(deny, "") {
+        // authorized (orchestrator) — perform the write
+        let res: String = op_write(content, typ, importance)
+        let new_id: String = json_get_string(res, "id")
+        let cp: String = json_set_str("{}", "node_id", new_id)
+        worktrack_append("swarm.committed", corr_id, "orchestrator", cp)
+        return res
+    }
+    // denied by capability — return the rejection, no engram mutation performed
+    return json_set_str("{}", "denied", deny)
+}
+
 // ── the coordinator: fan out -> track -> converge ────────────────────────────
 //
 //   blueprint        : task blueprint name run by every worker
@@ -426,6 +448,17 @@ fn swarm_run(blueprint: String, knowledge_refs: String, inputs_json: String, con
         let dp: String = json_set_str("{}", "strategy", strategy)
         worktrack_append("swarm.completed", corr_id, corr_id, dp)
 
+        // ── curated merge = the ONLY engram write path (Rule 4) ──
+        // With "commit":"1", the ORCHESTRATOR (its token carries engram:write)
+        // commits the approved merged geometry back to the engram. This is the
+        // single writer. Workers returned geometry; only the orchestrator writes.
+        let commit_id: String = ""
+        if str_eq(json_get_string(config_json, "commit"), "1") {
+            let orch_token: String = containment_coordinator_token(corr_id)
+            let cres: String = swarm_engram_write(orch_token, corr_id, "swarm-merge " + corr_id + " :: " + merged, "memory", 0.5)
+            let commit_id = json_get_string(cres, "id")
+        }
+
         let rep2: String = worktrack_swarm_report(corr_id)
         let ok2: [String] = el_list_empty()
         let ok2 = el_list_append(ok2, "corr_id")
@@ -435,7 +468,8 @@ fn swarm_run(blueprint: String, knowledge_refs: String, inputs_json: String, con
         let out1: String = json_build_object(ok2)
         let out2: String = json_set(out1, "report", rep2)
         let out3: String = json_set(out2, "merged", merged)
-        return json_set(out3, "telemetry", telemetry)
+        let out4: String = json_set(out3, "telemetry", telemetry)
+        return json_set_str(out4, "committed_node", commit_id)
     }
     // ── denied: caller was a worker trying to open a swarm (Rule 2) ──
     let dkv: [String] = el_list_empty()

lang/swarm/tests/harness_real_cognition.el

@@ -76,6 +76,39 @@ fn main() -> Int {
     let completed: Int = worktrack_count_kind(corr, "worker.completed")
     let fails = ok("work-tracking: 8 started + 8 completed", (started == 8) && (completed == 8), fails)
 
+    // ── G) RULE 4 — engram-write is @manager-ONLY (authority gate) ──
+    // A worker token (engram:read only) is STRUCTURALLY denied any engram write.
+    let worker_tok: String = containment_worker_token(corr, corr + "/worker-1")
+    let orch_tok: String = containment_coordinator_token(corr)
+    let fails = ok("worker token carries engram:read", containment_has_cap(worker_tok, "engram:read"), fails)
+    let fails = ok("worker token does NOT carry engram:write", !containment_has_cap(worker_tok, "engram:write"), fails)
+    let fails = ok("orchestrator token carries engram:write", containment_has_cap(orch_tok, "engram:write"), fails)
+    // a worker attempting an engram write is DENIED BY CAPABILITY (no HTTP issued)
+    let wdeny: String = swarm_engram_write(worker_tok, corr, "worker tries to mutate global state", "memory", 0.5)
+    let denied_reason: String = json_get_string(wdeny, "denied")
+    let fails = ok("worker engram-write DENIED by capability (Rule 4)", str_contains(denied_reason, "rule 4"), fails)
+    let fails = ok("denied worker write performed NO engram mutation (no node id)", str_eq(json_get_string(wdeny, "id"), ""), fails)
+    let fails = ok("Rule-4 violation journalled", worktrack_count_kind(corr, "containment.violation") >= 1, fails)
+    // the orchestrator passes the capability gate (sole authorized writer)
+    let odeny: String = containment_check_engram_write(orch_tok, "engram.write")
+    let fails = ok("orchestrator PASSES the engram-write capability gate (sole writer)", str_eq(odeny, ""), fails)
+
+    // ── H) curated merge = the only write path (orchestrator commits) ──
+    // The AUTHORITY gate above is already proven (worker denied, orchestrator
+    // authorized) WITHOUT issuing a write. The actual persisting commit exercises
+    // the engram write path, which needs the gate-1 write-healthy clone — so it
+    // runs only under SWARM_WRITE_HEALTHY=1 (else it would hit the known daemon
+    // write-crash). Authority != health: the gate holds either way.
+    if str_eq(env("SWARM_WRITE_HEALTHY"), "1") {
+        let cfg_commit: String = "{\"concurrency\":\"4\",\"strategy\":\"reduce\",\"min_success_ratio\":\"1.0\",\"commit\":\"1\"}"
+        let rc: String = swarm_run("cognize", refs, anchors, cfg_commit)
+        let committed: String = json_get_string(rc, "committed_node")
+        let fails2: Int = ok("orchestrator (sole writer) committed the merge to the engram", !str_eq(committed, ""), fails)
+        let fails = fails2
+    } else {
+        print("  note  curated-merge commit deferred to the gate-1 write-healthy clone (set SWARM_WRITE_HEALTHY=1); authority gate already proven above")
+    }
+
     print("")
     if fails == 0 {
         print("REAL-COGNITION SWARM GREEN — Neuron thinking in parallel over its own geometry.")