engram: intake realizes a signal into a manifold, it does not assume a node

There is no write node. What arrives at /api/write is a SIGNAL; a node is an
OUTPUT of realization, never an INPUT to it. route_write asserted otherwise in
one line:

    let manifold: String = "[" + body + "]"   // the body IS a valid manifold node object

A request body is not a manifold, and that assertion is the whole defect. It is
why every written signal landed as one flat node with zero edges, measured on a
clone: {"inserted":1,"nodes_added":1,"edges_added":0} and GET /api/neighbors on
the new id returning [].

PR #155 corrected transduce(signal, modality) to return a Manifold — components
plus relations — but touched only ingest, the runtime and its tests. Nothing
downstream called it: grep 'transduce|realize|Manifold|decompos' over
engram/src/server.el returned exactly one line, a comment. The primitive was
fixed and the engram's entire HTTP surface never reached for it.

This wires the intake seam to the primitive that already exists. It decomposes
nothing itself and must never: transduce dispatches through the dlsym realizer
registry, so adding a modality is registering a realizer, not editing this file
and not patching the runtime. intake_signal only carries what the primitive
returns into the store — components become nodes carrying their OWN geometry
via node_attach_geometry, relations become edges at the weight the realizer
stated, and manifold_member still wires the set into one connected sub-graph
exactly as insert_manifold_json already did.

Built general rather than special-cased: five of the six intake doors (write,
supersede, nodes, knowledge/capture, state-events) are the same hand-written
"content -> engram_node_full -> one flat node", differing only in the
node_type/tier/tags they hardcode. Those are parameters here so each door can
move onto this one function. Only /api/write rides it in this pass.

When no organ is registered the signal is stored flat exactly as before, but
the response now says so ("realized":false,"organ":false,"components":0).
Silent flattening was the real defect — a caller could not tell "nothing
decomposed me" from "I decomposed into one component". el_runtime.c draws the
same line between an absent organ and a broken one, for the same reason.

No realizer is authored here and none is registered, so production behaviour is
unchanged. The mechanism is what landed.

engram/src/server.el

@@ -1469,9 +1469,16 @@ fn route_guide_summon(method: String, path: String, body: String) -> String {
 //
 // The SINGLE NODE is the DEGENERATE n=1 case of this SAME operation — not a
 // separate CRUD path:
-//   write(content)     = reframe(region=∅,    manifold=[1 node])   (route_write)
+//   write(signal)      = realize(signal) → reframe(region=∅,    manifold)  (route_write)
 //   supersede(id,new)  = reframe(region={id}, manifold=[1 node])   (route_supersede)
 //   relate(a,b,rel)    = the rebind sub-op in isolation (route_create_edge)
+//
+// CORRECTED 2026-08-16: write was documented above as
+// "reframe(region=∅, manifold=[1 node])", and the "[1 node]" was not the design
+// — it was the DEFECT. A node is an OUTPUT of realization, never an INPUT to
+// it. What arrives at an intake route is a SIGNAL, and how many nodes it
+// becomes is for the realizer to say, not for the route to assume. See
+// "INTAKE" below.
 // The ONLY anti-pattern is decomposing a region-scale change into a LOOP of
 // independent top-level per-node updates. Here the region is the unit: one
 // isolate, one atomic set-replace, one persist, one verify — iterating members
@@ -1686,6 +1693,174 @@ fn reframe_core(region: [String], manifold: String, reason: String, do_rebind: I
         ",\"keystones_protected\":true}"
 }
 
+// ═══════════════════════════════════════════════════════════════════════════
+// INTAKE — the ONE door: signal → realization → manifold → store.
+//
+// THERE IS NO WRITE NODE. What arrives at an intake route is a SIGNAL. A node
+// is an OUTPUT of realization, never an INPUT to it. route_write used to say:
+//
+//     let manifold: String = "[" + body + "]"   // the body IS a valid manifold node object
+//
+// and hand that to reframe_core. That is not a manifold — it is the request
+// body wearing the word, and the comment stated the wrong assumption out loud.
+// It is why a compound signal landed as ONE flat node with ZERO edges. Measured
+// before this change, on a cp -Rc clone:
+//   POST /api/write {"type":"memory","content":"A cathedral is stone holding a
+//                    shape that stone alone would not hold."}
+//   → {"ok":true,"inserted":1,"nodes_added":1,"edges_added":0,...}
+//   GET /api/neighbors/<new id> → []      (read back out, not taken on trust)
+//
+// NOTHING IS DECOMPOSED HERE, AND NOTHING MAY EVER BE. transduce(signal,
+// modality) IS the realization primitive (el_runtime.c: "Manifold",
+// "Realizers + transduce"). It dispatches through the dlsym realizer registry,
+// so ADDING A MODALITY IS REGISTERING A REALIZER — never an edit to this file,
+// and never a patch to the runtime. This function only carries what the
+// primitive returns into the store, which is the one thing the engram's HTTP
+// surface has never done: `grep -n 'transduce\|realize\|Manifold\|decompos'
+// engram/src/server.el` returned exactly one line before this change, a comment.
+//
+// GENERAL BY CONSTRUCTION, NOT SPECIAL-CASED TO route_write. Five of the six
+// intake doors (write, supersede, nodes, neuron/knowledge/capture,
+// neuron/state-events) are the same hand-written "content string →
+// engram_node_full → one flat node", differing ONLY in the node_type / tier /
+// tags they hardcode. Those are parameters here, so each door can be moved onto
+// this one function as it is transitioned. Only /api/write rides it in this
+// pass; the rest are listed as remaining work.
+//
+// WHEN THERE IS NO ORGAN the signal is stored flat exactly as before, and the
+// response SAYS SO ("realized":false, "organ":false). Silent flattening is the
+// actual defect — a caller could not distinguish "nothing decomposed me" from
+// "I decomposed into one component". el_runtime.c draws the same line at
+// registration time, between an absent organ and a broken one, for the same
+// reason: those two must not look alike.
+// ═══════════════════════════════════════════════════════════════════════════
+
+// Resolve a component KEY to the node id it was inserted as. Components are
+// addressed BY KEY, never by index (el_runtime.c, "Manifold"), because the key
+// is what survives persistence — so relations are resolved by key too.
+fn key_to_id(keys: [String], ids: [String], key: String) -> String {
+    let n: Int = el_list_len(keys)
+    let i: Int = 0
+    while i < n {
+        if str_eq(el_list_get(keys, i), key) { return el_list_get(ids, i) }
+        i = i + 1
+    }
+    return ""
+}
+
+fn intake_signal(signal: String, modality: String, region: [String],
+                 nt_in: String, tier_in: String, tags: String,
+                 reason: String, do_rebind: Int) -> String {
+    let n_before: Int = engram_node_count()
+    let e_before: Int = engram_edge_count()
+    let region_n: Int = el_list_len(region)
+    let tomb: String = if region_n > 0 { supersede_set(region, reason) } else { "" }
+
+    // Identity can never be minted through intake — the same rule
+    // insert_manifold_json holds, applied at the one door instead of per-route.
+    let nt: String = if str_eq(nt_in, "") { "Memory" } else { nt_in }
+    if str_eq(nt, "self") { nt = "Memory" }
+    if str_eq(nt, "values") { nt = "Memory" }
+    let tier: String = if str_eq(tier_in, "") { "Working" } else { tier_in }
+
+    let has_organ: Int = realizer_has(modality)
+    let new_ids: [String] = el_list_empty()
+    let keys: [String] = el_list_empty()
+    let ncomp: Int = 0
+    let nrel: Int = 0
+    let realized: Int = 0
+
+    if has_organ > 0 {
+        let m: Manifold = transduce(signal, modality)
+        // A realizer that returns a bare Geometry transduces NOTHING by design
+        // (el_runtime.c) — manifold_is() is the check, so a fingerprinting organ
+        // is not silently mistaken for a decomposing one.
+        if manifold_is(m) > 0 {
+            realized = 1
+            ncomp = manifold_size(m)
+            let i: Int = 0
+            let prev: String = ""
+            while i < ncomp {
+                let key: String = manifold_key(m, i)
+                let role: String = manifold_role(m, i)
+                // The component's OWN geometry, at its own width — this is the
+                // whole point of a manifold over a fingerprint, and it is why
+                // node_attach_geometry is used rather than re-embedding the
+                // component's name as text.
+                let g: Geometry = manifold_geometry(m, i)
+                let ctags: String = "[\"component\",\"role:" + role + "\",\"modality:" + modality + "\"]"
+                let cid: String = engram_node_full(key, nt, key, 0.5, 0.5, 0.9, tier, ctags)
+                let landed: Int = node_attach_geometry(cid, g)
+                let freed: Int = geometry_free(g)
+                new_ids = el_list_append(new_ids, cid)
+                keys = el_list_append(keys, key)
+                // PRESERVED CONTRACT: manifold_member wires the inserted set
+                // into one connected sub-graph, exactly as insert_manifold_json
+                // already did. Not reinvented — reused.
+                if !str_eq(prev, "") { engram_connect(prev, cid, 0.6, "manifold_member") }
+                prev = cid
+                i = i + 1
+            }
+            // THE RELATIONS ARE THE CONTENT. Relation weight IS the grounding
+            // (correspondence-and-censorship §1) — it arrives on the edge from
+            // the realizer and nothing here computes or second-guesses it.
+            nrel = manifold_rel_count(m)
+            let j: Int = 0
+            while j < nrel {
+                let fk: String = manifold_rel_from(m, j)
+                let rn: String = manifold_rel_name(m, j)
+                let tk: String = manifold_rel_to(m, j)
+                let w: Float = manifold_rel_weight(m, j)
+                let fid: String = key_to_id(keys, new_ids, fk)
+                let tid: String = key_to_id(keys, new_ids, tk)
+                if !str_eq(fid, "") {
+                    if !str_eq(tid, "") {
+                        engram_connect(fid, tid, w, rn)
+                    }
+                }
+                j = j + 1
+            }
+            let mfreed: Int = manifold_free(m)
+        }
+    }
+
+    // NO ORGAN: store the signal flat, as before — but say so. This is the
+    // pre-existing behaviour preserved verbatim, not a new fallback path.
+    if realized == 0 {
+        let label: String = str_slice(signal, 0, 60)
+        let fid: String = engram_node_full(signal, nt, label, 0.5, 0.5, 0.9, tier, tags)
+        new_ids = el_list_append(new_ids, fid)
+    }
+
+    let inserted: Int = el_list_len(new_ids)
+    let bound: Int = if do_rebind > 0 { rebind_cosine(new_ids, tomb) } else { 0 }
+    let saved: Int = persist_canonical()
+    let new_csv: String = ""
+    let k: Int = 0
+    while k < inserted {
+        let sep: String = if k == 0 { "" } else { "," }
+        new_csv = new_csv + sep + "\"" + el_list_get(new_ids, k) + "\""
+        k = k + 1
+    }
+    let realized_s: String = if realized > 0 { "true" } else { "false" }
+    let organ_s: String = if has_organ > 0 { "true" } else { "false" }
+    return "{\"ok\":true,\"region_superseded\":" + int_to_str(region_n) +
+        ",\"tombstone_id\":\"" + tomb + "\"" +
+        ",\"inserted\":" + int_to_str(inserted) +
+        ",\"new_ids\":[" + new_csv + "]" +
+        ",\"edges_rebound\":" + int_to_str(bound) +
+        ",\"realized\":" + realized_s +
+        ",\"modality\":\"" + modality + "\"" +
+        ",\"organ\":" + organ_s +
+        ",\"components\":" + int_to_str(ncomp) +
+        ",\"relations\":" + int_to_str(nrel) +
+        ",\"nodes_added\":" + int_to_str(engram_node_count() - n_before) +
+        ",\"edges_added\":" + int_to_str(engram_edge_count() - e_before) +
+        ",\"node_count\":" + int_to_str(engram_node_count()) +
+        ",\"edge_count\":" + int_to_str(engram_edge_count()) +
+        ",\"keystones_protected\":true}"
+}
+
 // POST /api/reframe — the universal set-based mutation.
 // Body: {vantage?, region_ids?(csv), k?, expand?, manifold(json array), reason?, rebind?}
 // region_ids (explicit) wins; else cosine-isolate around vantage.
@@ -1722,18 +1897,32 @@ fn route_reframe(method: String, path: String, body: String) -> String {
     return reframe_core(region, manifold, reason, do_rebind)
 }
 
-// write — DEGENERATE n=1 of reframe: region=∅, manifold=[1 node]. The SAME
-// reframe_core path. rebind off so the pure-add matches plain node creation.
-// POST /api/write  {content, node_type?, tier?, tags?}
+// write — INTAKE OF A SIGNAL. Not "reframe with a manifold of one node": the
+// route no longer decides how many nodes the signal is. It hands the signal to
+// the realization primitive and stores whatever manifold comes back.
+//
+// The line this replaces was:
+//     let manifold: String = "[" + body + "]"   // the body IS a valid manifold node object
+// which asserted that a request body is a manifold. It is not, and that single
+// assertion is the whole measured defect (1 node, 0 edges, [] neighbors).
+//
+// rebind stays off so a pure add still matches plain node creation.
+// POST /api/write  {content, modality?, node_type?, tier?, tags?}
 fn route_write(method: String, path: String, body: String) -> String {
     let content: String = json_get_string(body, "content")
     if str_eq(content, "") { return err_json("write: content required") }
     let nt: String = json_get_string(body, "node_type")
     if str_eq(nt, "self") { return err_json("write: identity is write-protected") }
     if str_eq(nt, "values") { return err_json("write: identity is write-protected") }
+    // The modality names which organ to sense with. It is data, never a branch:
+    // a new modality is a realizer_register call somewhere else in the program,
+    // not another endpoint and not another case here.
+    let mod_raw: String = json_get_string(body, "modality")
+    let modality: String = if str_eq(mod_raw, "") { "text" } else { mod_raw }
+    let tier: String = json_get_string(body, "tier")
+    let tags: String = json_get_raw(body, "tags")
     let empty: [String] = el_list_empty()
-    let manifold: String = "[" + body + "]"   // the body IS a valid manifold node object
-    return reframe_core(empty, manifold, "write", 0)
+    return intake_signal(content, modality, empty, nt, tier, tags, "write", 0)
 }
 
 // supersede — DEGENERATE n=1 of reframe: region={id}, manifold=[1 node]. The