diff --git a/next/tests/http_publish_fold.sh b/next/tests/http_publish_fold.sh
new file mode 100755
index 00000000..9391f92b
--- /dev/null
+++ b/next/tests/http_publish_fold.sh
@@ -0,0 +1,133 @@
+#!/usr/bin/env bash
+# next/tests/http_publish_fold.sh — Step 9-pre-fold integration.
+#
+# Proves the full POST → publish → broadcast → projection-fold
+# chain through HTTP without a real TCP socket. The kernel
+# orchestrator threads :projections into the publish Context,
+# so outbox:publish broadcasts the signed activity to every
+# registered projection process and each fold runs.
+#
+# Step 9a/b smoke tests will exercise the same path via curl
+# once Step 8b-start lights up actual TCP. 10 cases.
+
+set -uo pipefail
+cd "$(git rev-parse --show-toplevel)"
+
+SX_SERVER="${SX_SERVER:-hosts/ocaml/_build/default/bin/sx_server.exe}"
+if [ ! -x "$SX_SERVER" ]; then
+  SX_SERVER="/root/rose-ash/hosts/ocaml/_build/default/bin/sx_server.exe"
+fi
+if [ ! -x "$SX_SERVER" ]; then
+  echo "ERROR: sx_server.exe not found." >&2
+  exit 1
+fi
+
+VERBOSE="${1:-}"
+PASS=0; FAIL=0; ERRORS=""
+TMPFILE=$(mktemp); trap "rm -f $TMPFILE" EXIT
+
+PRELUDE='KM = <<1,2,3,4>>, KS = [{key_id,k1},{algorithm,ed25519},{value,KM}], AS = [{public_keys,[[{id,k1},{created,0},{value,KM}]]}], projection:start_link(p_count, 0, fun (_A, S) -> S + 1 end), projection:start_link(p_collect, [], fun (A, S) -> [A | S] end), nx_kernel:start_link(alice, KS, AS), nx_kernel:with_projections([p_count, p_collect]), Token = <<102,111,111>>, AuthKey = <<97,117,116,104,111,114,105,122,97,116,105,111,110>>, AuthVal = <<66,101,97,114,101,114,32,102,111,111>>, Cfg = [{publish_token, Token}], BuildReq = fun (B) -> [{method, <<80,79,83,84>>}, {path, http_server:activity_path()}, {headers, [{AuthKey, AuthVal}]}, {body, B}] end,'
+
+cat > "$TMPFILE" <<EPOCHS
+(epoch 1)
+(load "lib/erlang/tokenizer.sx")
+(load "lib/erlang/parser.sx")
+(load "lib/erlang/parser-core.sx")
+(load "lib/erlang/parser-expr.sx")
+(load "lib/erlang/parser-module.sx")
+(load "lib/erlang/transpile.sx")
+(load "lib/erlang/runtime.sx")
+(load "lib/erlang/vm/dispatcher.sx")
+(epoch 2)
+(eval "(er-load-gen-server!)")
+(epoch 3)
+(eval "(get (erlang-load-module (file-read \"next/kernel/envelope.erl\")) :name)")
+(epoch 4)
+(eval "(get (erlang-load-module (file-read \"next/kernel/log.erl\")) :name)")
+(epoch 5)
+(eval "(get (erlang-load-module (file-read \"next/kernel/pipeline.erl\")) :name)")
+(epoch 6)
+(eval "(get (erlang-load-module (file-read \"next/kernel/projection.erl\")) :name)")
+(epoch 7)
+(eval "(get (erlang-load-module (file-read \"next/kernel/outbox.erl\")) :name)")
+(epoch 8)
+(eval "(get (erlang-load-module (file-read \"next/kernel/nx_kernel.erl\")) :name)")
+(epoch 9)
+(eval "(get (erlang-load-module (file-read \"next/kernel/http_server.erl\")) :name)")
+
+;; Single authorized POST advances both projection counters
+(epoch 10)
+(eval "(erlang-eval-ast \"${PRELUDE} http_server:route(BuildReq(<<104,105>>), Cfg), projection:query(p_count)\")")
+
+(epoch 11)
+(eval "(erlang-eval-ast \"${PRELUDE} http_server:route(BuildReq(<<104,105>>), Cfg), length(projection:query(p_collect))\")")
+
+;; Three POSTs -> both projections at 3
+(epoch 12)
+(eval "(get (erlang-eval-ast \"${PRELUDE} http_server:route(BuildReq(<<104,105>>), Cfg), http_server:route(BuildReq(<<104,105>>), Cfg), http_server:route(BuildReq(<<104,105>>), Cfg), {projection:query(p_count), length(projection:query(p_collect))} =:= {3, 3}\") :name)")
+
+;; Log tip and projection counter agree
+(epoch 13)
+(eval "(get (erlang-eval-ast \"${PRELUDE} http_server:route(BuildReq(<<104,105>>), Cfg), http_server:route(BuildReq(<<104,105>>), Cfg), {nx_kernel:log_tip(), projection:query(p_count)} =:= {2, 2}\") :name)")
+
+;; Unauthorized POST does NOT advance projection state
+(epoch 14)
+(eval "(erlang-eval-ast \"${PRELUDE} BadAuth = <<66,101,97,114,101,114,32,98,97,100>>, BadReq = [{method, <<80,79,83,84>>}, {path, http_server:activity_path()}, {headers, [{AuthKey, BadAuth}]}, {body, <<104,105>>}], http_server:route(BadReq, Cfg), projection:query(p_count)\")")
+
+;; Sig-failed POST does NOT advance projection state (kernel rejects)
+(epoch 15)
+(eval "(erlang-eval-ast \"OtherKM = <<9,9,9,9>>, BadKS = [{key_id,k1},{algorithm,ed25519},{value,OtherKM}], AS = [{public_keys,[[{id,k1},{created,0},{value,<<1,2,3,4>>}]]}], projection:start_link(p_count, 0, fun (_A, S) -> S + 1 end), nx_kernel:start_link(alice, BadKS, AS), nx_kernel:with_projections([p_count]), Token = <<102,111,111>>, AuthKey = <<97,117,116,104,111,114,105,122,97,116,105,111,110>>, AuthVal = <<66,101,97,114,101,114,32,102,111,111>>, Cfg = [{publish_token, Token}], Req = [{method, <<80,79,83,84>>}, {path, http_server:activity_path()}, {headers, [{AuthKey, AuthVal}]}, {body, <<>>}], http_server:route(Req, Cfg), projection:query(p_count)\")")
+
+;; The body posted is what the projection sees inside the activity's :object
+(epoch 16)
+(eval "(get (erlang-eval-ast \"${PRELUDE} http_server:route(BuildReq(<<120,121,122>>), Cfg), [Act] = projection:query(p_collect), case envelope:get_field(object, Act) of {ok, <<120,121,122>>} -> ok; _ -> bad end\") :name)")
+
+;; Three POSTs -> log entries match (round-trip via the kernel log)
+(epoch 17)
+(eval "(erlang-eval-ast \"${PRELUDE} http_server:route(BuildReq(<<104,105>>), Cfg), http_server:route(BuildReq(<<104,105>>), Cfg), http_server:route(BuildReq(<<104,105>>), Cfg), length(log:entries(nx_kernel:log_state(nx_kernel:query())))\")")
+
+;; Single POST: projection seq number proves fold ran (state changed)
+(epoch 18)
+(eval "(get (erlang-eval-ast \"${PRELUDE} http_server:route(BuildReq(<<104,105>>), Cfg), projection:query(p_count) =/= 0\") :name)")
+EPOCHS
+
+OUTPUT=$(timeout 300 "$SX_SERVER" < "$TMPFILE" 2>/dev/null)
+
+check() {
+  local epoch="$1" desc="$2" expected="$3"
+  local actual
+  actual=$(echo "$OUTPUT" | awk -v e="$epoch" '
+    $0 ~ "^\\(ok-len " e " " { getline; print; exit }
+    $0 ~ "^\\(ok " e " "     { print; exit }
+    $0 ~ "^\\(error " e " "  { print; exit }
+  ')
+  [ -z "$actual" ] && actual="<no output for epoch $epoch>"
+  if echo "$actual" | grep -qF -- "$expected"; then
+    PASS=$((PASS+1))
+    [ "$VERBOSE" = "-v" ] && echo "  ok $desc"
+  else
+    FAIL=$((FAIL+1))
+    ERRORS+="  FAIL [$desc] (epoch $epoch) expected: $expected | actual: $actual
+"
+  fi
+}
+
+check  9  "http_server loaded"                "http_server"
+check 10  "POST -> p_count = 1"               "1"
+check 11  "POST -> p_collect length = 1"      "1"
+check 12  "three POSTs -> both at 3"          "true"
+check 13  "log_tip == p_count"                "true"
+check 14  "unauthorized POST no fold"         "0"
+check 15  "sig failure no fold"               "0"
+check 16  "projection sees body as :object"   "ok"
+check 17  "log entries = 3 after 3 POSTs"     "3"
+check 18  "single POST changes proj state"    "true"
+
+TOTAL=$((PASS+FAIL))
+if [ $FAIL -eq 0 ]; then
+  echo "ok $PASS/$TOTAL next/tests/http_publish_fold.sh passed"
+else
+  echo "FAIL $PASS/$TOTAL passed, $FAIL failed:"
+  echo "$ERRORS"
+fi
+[ $FAIL -eq 0 ]
diff --git a/plans/fed-sx-milestone-1.md b/plans/fed-sx-milestone-1.md
index e03524bc..c6c132be 100644
--- a/plans/fed-sx-milestone-1.md
+++ b/plans/fed-sx-milestone-1.md
@@ -571,6 +571,11 @@ Auth on `POST /activity`: bearer token from env var `NEXT_PUBLISH_TOKEN`.
 
 ## Step 9 — Smoke tests
 
+**Sub-deliverables:**
+- [x] **9-pre-fold** — In-process end-to-end test of the HTTP → publish → broadcast → projection-fold chain. Proves the full vertical works without a real TCP socket. `next/tests/http_publish_fold.sh` (10 cases). Step 9a/b proper need TCP (Step 8b-start).
+- [ ] **9a** — Pin smoke test (TCP-driven, curl) — needs Step 8b-start + Define\* SX-source eval.
+- [ ] **9b** — Reactive smoke test (TCP-driven, curl) — needs DefineSubscription / DefineTrigger eval.
+
 **The proof points.** Two end-to-end smoke tests demonstrate, between them, that
 fed-sx is genuinely a substrate for distributed reactive applications expressed
 as data — not a system you extend by writing kernel code.
@@ -991,6 +996,7 @@ A few things still under-specified; resolve as work begins.
 Newest first. One line per sub-deliverable commit. Erlang conformance gate
 (`bash lib/erlang/conformance.sh`) must remain 729/729 on every entry.
 
+- **2026-05-28** — Step 9-pre-fold: in-process integration test proving the full POST → publish → broadcast → projection-fold chain. With `projection:start_link` + `nx_kernel:start_link` + `nx_kernel:with_projections([p_count, p_collect])`, three authorized POST `/activity` calls advance both projections to 3 — and the kernel's log to 3 entries — and the projection's collected activity carries the POST body as `:object`. Unauthorized or sig-failed POSTs leave projection state unchanged. Step 9a/b proper (curl-driven smoke tests) wait on Step 8b-start (TCP) + Define\* SX-source eval bridge, but the structural chain is already verified end-to-end. `next/tests/http_publish_fold.sh` 10/10. Erlang conformance 729/729. Step 9 split into 9-pre-fold (done) + 9a + 9b.
 - **2026-05-28** — Step 8c-post-publish-http: POST `/activity` handler now bridges into `nx_kernel:publish/1` when the kernel gen_server is registered (`erlang:whereis(nx_kernel) =/= undefined`). On success the response carries the canonical CID via `cid_response/1`; on pipeline failure the response is 422 via `validation_failed_response/0`. When the kernel isn't registered, the handler falls through to the existing 200 stub — preserves backwards compatibility for the auth-only tests in `http_post_activity.sh`. Distinct POSTs produce distinct CIDs (next_published counter in nx_kernel state). Unauthorized POSTs never reach the kernel — log tip stays at 0. `next/tests/http_publish.sh` 10/10. The POST `/activity` → publish → fold loop is now functional end-to-end through the kernel. Erlang conformance 729/729.
 - **2026-05-28** — Step 8c-post-publish-srv: `nx_kernel.erl` extended with gen_server callbacks + named-process API. `start_link/3(ActorId, KeySpec, ActorState)` spawns the worker and registers under the literal `nx_kernel` atom; `publish/1(Request)` calls into `handle_call({publish, Request}, ...)` which delegates to the pure `publish/2` and reflects the new state back into the server. `query/0` returns the full state proplist; `log_tip/0` is a direct accessor; `with_projections/1` mutates the projections list. Same port quirks as Step 5b/7b documented (raw Pid return, no `?MODULE`, processes don't persist across separate `erlang-eval-ast` calls — tests inline start_link with operations). `next/tests/nx_kernel_server.sh` 11/11. Erlang conformance 729/729.
 - **2026-05-28** — Step 8c-post-publish-pure: `next/kernel/nx_kernel.erl` — pure-functional kernel orchestrator that wraps `outbox:publish/2` with a long-lived runtime state. `new/3(ActorId, KeySpec, ActorState)` initialises state with an empty log + monotonic `:next_published` counter. `publish/2(Request, State)` builds the publish Context from state, calls outbox:publish, and on success advances `:log` and increments `:next_published`. The counter solves the "same Request published twice" replay collision — each call gets a distinct `:published` timestamp, so the canonical-bytes CID differs and stage_replay doesn't halt. On failure (e.g. bad key), state is returned unchanged. Step 8c-post-publish split into pure (done) + srv (gen_server wrapper) sub-deliverables. `next/tests/nx_kernel_pure.sh` 12/12. Erlang conformance 729/729.