diff --git a/.omp/extensions/fm-primary-omp.ts b/.omp/extensions/fm-primary-omp.ts
index 1f48159a202..1533d70cc42 100644
--- a/.omp/extensions/fm-primary-omp.ts
+++ b/.omp/extensions/fm-primary-omp.ts
@@ -252,7 +252,31 @@ export default function (omp: ExtensionAPI) {
 
   const deliverSessionstartNudge = (forceForNativeSwitch = false): void => {
     watch.markLoaded();
-    pendingStartupNudge = runSessionstartNudge(forceForNativeSwitch);
+    const nudge = runSessionstartNudge(forceForNativeSwitch);
+    if (!forceForNativeSwitch) {
+      pendingStartupNudge = nudge;
+      return;
+    }
+    // A native /new or /resume switch replaces the conversation while this
+    // process still owns the lock, so the watcher re-arms immediately and its
+    // first wake can start an agent-initiated turn. OMP never emits
+    // before_agent_start for such a turn, nor for a captain prompt queued into
+    // it, so a nudge staged for before_agent_start would stay parked past the
+    // new session's first turn. Append the instruction to the replacement
+    // session's context right now instead, ahead of any wake, and leave nothing
+    // staged so the next before_agent_start cannot deliver it a second time.
+    pendingStartupNudge = "";
+    if (!nudge) return;
+    omp.sendMessage(
+      {
+        customType: "firstmate-sessionstart-nudge",
+        content: nudge,
+        display: false,
+        attribution: "agent",
+        details: { kind: "session-start", runtime: "omp" },
+      },
+      { deliverAs: "nextTurn" },
+    );
   };
 
   omp.on("session_start", (_event, ctx) => {
diff --git a/docs/sessionstart-nudge.md b/docs/sessionstart-nudge.md
index 105fa3fbaa9..479ec33cff1 100644
--- a/docs/sessionstart-nudge.md
+++ b/docs/sessionstart-nudge.md
@@ -24,7 +24,7 @@ Every path exits 0, including malformed state and adapter errors, because a Clau
 | Codex | `.codex/hooks.json` anchors to the hook process working directory, verifies a Firstmate-shaped hook-bearing root, and executes the wrapper. | Native stdout context injection is supported. |
 | OpenCode | `.opencode/plugins/fm-primary-sessionstart-nudge.js` listens for `session.created`, runs once per session id, and calls `client.session.promptAsync` only when the wrapper prints a nudge. | Interactive TUI delivery is supported; headless `opencode run` is intentionally fail-open because the process can exit before the queued turn. |
 | Pi / pi-signed | `.pi/extensions/fm-primary-turnend-guard.ts` handles `session_start` reasons `startup`, `new`, and `resume`, then injects the wrapper output with `pi.sendMessage`. | The custom message reaches model context without racing an initial positional prompt. |
-| OMP | `.omp/extensions/fm-primary-omp.ts` runs the wrapper on native `session_start` and `session_switch`, then injects the result as one hidden `before_agent_start` message. A native `/new` or `/resume` switch re-injects the same typed instruction directly instead of through the wrapper, which stays silent while this session still holds the lock. | The custom message reaches model context without racing the launch prompt, and native project discovery loads the adapter without a trust prompt. |
+| OMP | `.omp/extensions/fm-primary-omp.ts` runs the wrapper on native `session_start` and injects the result as one hidden `before_agent_start` message bound to the launch prompt. A native `/new` or `/resume` switch instead appends the same typed instruction to the replacement session's context at once through `sendMessage` without starting a turn: the wrapper stays silent while this session still holds the lock, and the restored watcher's first wake can start an agent-initiated turn that never reaches `before_agent_start`. `/fork` still invokes the wrapper silently under the held lock, and OMP reloads likewise keep that wrapper invocation silent while following the native `resume` switch transport. | The custom message reaches model context without racing the launch prompt or the restored watcher's first wake, and native project discovery loads the adapter without a trust prompt. |
 | Grok | `.grok/hooks/fm-primary-sessionstart-nudge.json` registers a project `SessionStart` hook and invokes the wrapper through inline-defaulted `${GROK_WORKSPACE_ROOT:-}`. | The project hook runs when the checkout is trusted, but Grok currently discards hook stdout from model context, so this path is intentionally fail-open. |
 
 The OpenCode nudge runs only on `session.created`.
@@ -38,7 +38,8 @@ That alternative expands trust and writes outside this repository, so Firstmate
 `tests/fm-sessionstart-nudge.test.sh` proves wrapper silence for both gate signals, an unmarked linked worktree, a missing state directory, and an already-owned lock.
 It proves exact U+2063 `FIRSTMATE_OP:`-prefixed, `session-start`-typed one-line output for a plain primary and a marked linked secondmate primary.
 `tests/fm-pi-primary-live-e2e.test.sh` and `tests/fm-opencode-primary-live-e2e.test.sh` exercise native startup paths with first-message and later-message Ahoy regressions.
-`tests/fm-omp-primary-live-e2e.test.sh` covers OMP's native discovery and once-only startup delivery, including a `/new` switch and an exact-session resume launch.
+`tests/fm-omp-primary.test.sh` proves each in-process `/new` and `/resume` switch appends exactly one instruction without staging a second copy, including a second `/new` with no `before_agent_start` in between, while `/fork` stays silent under the held lock.
+`tests/fm-omp-primary-live-e2e.test.sh` covers OMP's native discovery and once-only startup delivery, including two consecutive `/new` switches whose instruction precedes each new session's first assistant turn, and an exact-session resume launch.
 `tests/fm-turnend-guard.test.sh`, `tests/fm-pi-watch-extension.test.sh`, and `tests/fm-daemon.test.sh` cover marked guard, monitoring, and away-mode delivery.
 
 [`verification/supervision.md`](verification/supervision.md#native-session-start-delivery) records the active version-scoped transport evidence.
diff --git a/docs/supervision-protocols/omp.md b/docs/supervision-protocols/omp.md
index 64be49f6df0..c78e01ce413 100644
--- a/docs/supervision-protocols/omp.md
+++ b/docs/supervision-protocols/omp.md
@@ -12,7 +12,7 @@ When this session owns supervision and away mode is not active:
 6. The extension starts `bin/fm-watch-arm.sh --restart`, keeps the child attached to the live OMP process, and owns every later successor launch.
    The tool and the fallback command return only after that child reports readiness, so a `watcher: FAILED` readiness timeout is a real failure to handle under step 11 rather than a slow success.
 7. OMP `/new`, `/resume`, `/fork`, and session reload emit `session_switch`, replace the prior extension generation, and restore the watcher without a foreground watcher command.
-   `/new` and `/resume` also inject the session-start instruction exactly once for the new conversation.
+   `/new` and `/resume` also append the session-start instruction exactly once to the new conversation, ahead of the restored watcher's first wake.
 8. After an actionable child close, the shared watcher core rechecks session-lock ownership and verifies one successor before it delivers the follow-up notification; a replacement generation receives an actionable close whose prior delivery was not yet consumed.
 9. Ordinary work, turn completion, and ordinary notification handling must not call `fm_watch_arm_omp` again because continuity is extension-owned.
 10. An unexpected child close enters bounded exponential retry, and an exhausted retry or lost session lock is surfaced as a watcher failure.
diff --git a/docs/verification/supervision.md b/docs/verification/supervision.md
index 2d9dc531e63..fa64afae168 100644
--- a/docs/verification/supervision.md
+++ b/docs/verification/supervision.md
@@ -114,6 +114,18 @@ ok - OMP omp/17.2.10 primary E2E proved watcher delivery with an intact editable
 ```
 
 The live guard observed the watcher wake in the OMP session and found the exact draft unchanged after delivery.
+The OMP 18.1.5 repeated-`/new` delivery guard ran on 2026-09-05 after the adapter began appending the replacement instruction through `sendMessage` at switch time; the guard now drives two consecutive `/new` switches and requires each new session's instruction to precede its first assistant record.
+
+```sh
+FM_OMP_PRIMARY_LIVE_E2E=1 bin/fm-test-run.sh tests/fm-omp-primary-live-e2e.test.sh
+```
+
+```text
+ok - OMP omp/18.1.5 primary E2E proved fresh no-state and ordinary native discovery, exact ownership, once-only startup, guarded watcher startup, repeated /new continuity, shutdown, resume, and away-mode delivery
+ok - OMP omp/18.1.5 primary E2E proved watcher delivery with an intact editable draft
+```
+
+Before that change the same guard failed on OMP 18.1.5 at the first `/new`: the restored watcher's first wake started an agent-initiated turn, and OMP emits `before_agent_start` neither for that turn nor for a captain prompt queued into it, so an instruction staged for `before_agent_start` never reached the replacement session.
 
 Standalone OMP executable compatibility is recorded in [runtime backend verification](runtime-backends.md#omp-lifecycle).
 
@@ -354,8 +366,8 @@ FM_OMP_PRIMARY_LIVE_E2E=1 bin/fm-test-run.sh tests/fm-omp-primary-live-e2e.test.
 not ok - OMP /new did not inject exactly one startup instruction for the new session
 ```
 
-The identical pre-port failure establishes a pre-existing OMP 18.1.5 session-start-nudge compatibility finding rather than a watcher-continuity regression.
-The provider-free adapter regression remains the current proof that its `/new` and `/resume` replacement handlers each stage one nudge while re-arming, and the live guard remains intentionally red until that separate compatibility finding is resolved.
+The identical pre-port failure established a pre-existing OMP 18.1.5 session-start-nudge compatibility finding rather than a watcher-continuity regression.
+That finding was resolved on 2026-09-05; the [native session-start delivery](#native-session-start-delivery) section records the passing repeated-`/new` guard, and `tests/fm-omp-primary.test.sh` keeps the provider-free proof that each `/new` and `/resume` replacement handler appends exactly one instruction while re-arming, including a second `/new` with no `before_agent_start` in between.
 The remaining primary harnesses are not applicable because they do not bind the shared Pi-compatible extension generation lifecycle.
 
 The once-per-generation recovery bound and immediate handling-successor poll were verified on 2026-08-21 at revision `549dd1e0ff05f96607c5e7457b4d8e3d7396bd16` with the tracked Pi extension, real watcher processes, and an isolated home.
diff --git a/tests/fm-omp-primary-live-e2e.test.sh b/tests/fm-omp-primary-live-e2e.test.sh
index 21d703e3cf8..ca337bc45a4 100755
--- a/tests/fm-omp-primary-live-e2e.test.sh
+++ b/tests/fm-omp-primary-live-e2e.test.sh
@@ -174,6 +174,28 @@ wait_pid_change() {
   return 1
 }
 
+# The replacement session's instruction must already be in context when its
+# first turn starts, whether the restored watcher's first wake or a captain
+# prompt starts that turn.
+session_nudge_precedes_first_assistant() {  # <session-file>
+  node -e '
+    const lines = require("node:fs").readFileSync(process.argv[1], "utf8").trimEnd().split("\n");
+    let nudge = -1;
+    let assistant = -1;
+    lines.forEach((line, index) => {
+      let entry;
+      try { entry = JSON.parse(line); } catch { return; }
+      if (nudge < 0 && entry.type === "custom_message" && entry.customType === "firstmate-sessionstart-nudge") nudge = index;
+      if (assistant < 0 && entry.message?.role === "assistant") assistant = index;
+    });
+    process.exit(nudge >= 0 && (assistant < 0 || nudge < assistant) ? 0 : 1);
+  ' "$1"
+}
+
+newest_session_file() {
+  find "$SESSION_DIR" -maxdepth 1 -type f -name '*.jsonl' -print | sort | tail -n 1
+}
+
 submit_omp() {
   local text=$1 bun bin
   bun=$(sed -n '3p' "$MARKER")
@@ -269,6 +291,29 @@ done
 [ "${sessions_after:-0}" -gt "$sessions_before" ] || fail "OMP /new did not create a native session"
 [ "$(grep -Rhc '"customType":"firstmate-sessionstart-nudge"' "$SESSION_DIR"/*.jsonl | awk '{s+=$1} END{print s+0}')" -eq 2 ] \
   || fail "OMP /new did not inject exactly one startup instruction for the new session"
+session_nudge_precedes_first_assistant "$(newest_session_file)" \
+  || fail "OMP /new startup instruction did not precede the new session's first assistant turn"
+
+# A second /new must deliver its own instruction even though the first
+# replacement's turn may have been started by the restored watcher rather than
+# by a captain prompt.
+sessions_before=$sessions_after
+submit_omp /new || fail "OMP second /new command was not submitted"
+third_watch_pid=$(wait_pid_change "$WATCH_LOCK" "$second_watch_pid") \
+  || fail "OMP second /new did not replace and restore the extension-owned watcher generation"
+submit_omp 'Reply exactly OMP_SECOND_NEW_READY.' || fail "second new OMP session did not accept a prompt"
+wait_text OMP_SECOND_NEW_READY || fail "second new OMP session did not complete its first turn"
+for _ in $(seq 1 240); do
+  sessions_after=$(find "$SESSION_DIR" -maxdepth 1 -type f -name '*.jsonl' | wc -l | tr -d ' ')
+  [ "$sessions_after" -gt "$sessions_before" ] && break
+  sleep 0.25
+done
+[ "${sessions_after:-0}" -gt "$sessions_before" ] || fail "OMP second /new did not create a native session"
+[ "$(grep -Rhc '"customType":"firstmate-sessionstart-nudge"' "$SESSION_DIR"/*.jsonl | awk '{s+=$1} END{print s+0}')" -eq 3 ] \
+  || fail "OMP second /new did not inject exactly one startup instruction for its new session"
+session_nudge_precedes_first_assistant "$(newest_session_file)" \
+  || fail "OMP second /new startup instruction did not precede its session's first assistant turn"
+second_watch_pid=$third_watch_pid
 
 submit_omp /exit || fail "OMP primary /exit was not submitted"
 for _ in $(seq 1 240); do
@@ -296,7 +341,7 @@ second_omp_pid=$(sed -n '2p' "$MARKER")
 [ "$second_omp_pid" = "$(cat "$LOCK")" ] || fail "OMP resume did not bind the lock to the new process"
 resume_watch_pid=$(wait_pid_change "$WATCH_LOCK" "$second_watch_pid") \
   || fail "OMP resume did not restore a live watcher generation"
-[ "$(grep -Rhc '"customType":"firstmate-sessionstart-nudge"' "$SESSION_DIR"/*.jsonl | awk '{s+=$1} END{print s+0}')" -eq 3 ] \
+[ "$(grep -Rhc '"customType":"firstmate-sessionstart-nudge"' "$SESSION_DIR"/*.jsonl | awk '{s+=$1} END{print s+0}')" -eq 4 ] \
   || fail "OMP process resume did not add exactly one fresh startup instruction"
 kill -0 "$resume_watch_pid" 2>/dev/null || fail "OMP resume watcher is not live"
 
@@ -322,7 +367,7 @@ grep -R -F 'OMP_AWAY_DELIVERY' "$SESSION_DIR"/*.jsonl >/dev/null 2>&1 \
 grep -R -F 'away-supervisor' "$SESSION_DIR"/*.jsonl >/dev/null 2>&1 \
   || fail "OMP away-mode notification lost its operational-input kind"
 wait_idle || fail "OMP $OMP_VERSION did not reach an idle boundary after away-mode delivery"
-printf 'ok - OMP %s primary E2E proved fresh no-state and ordinary native discovery, exact ownership, once-only startup, guarded watcher startup, /new continuity, shutdown, resume, and away-mode delivery\n' \
+printf 'ok - OMP %s primary E2E proved fresh no-state and ordinary native discovery, exact ownership, once-only startup, guarded watcher startup, repeated /new continuity, shutdown, resume, and away-mode delivery\n' \
   "$OMP_VERSION"
 draft="human-draft-survives-omp-watcher-wake"
 PATH="$WRAPPER_BIN:$PATH" tmux send-keys -t "$TARGET" -l "$draft"
diff --git a/tests/fm-omp-primary.test.sh b/tests/fm-omp-primary.test.sh
index 5dafa540cf7..fdc7e26a995 100755
--- a/tests/fm-omp-primary.test.sh
+++ b/tests/fm-omp-primary.test.sh
@@ -536,24 +536,49 @@ if (await handlers.get("before_agent_start")({ type: "before_agent_start" }, {})
   throw new Error("startup nudge repeated within one OMP session");
 }
 writeFileSync(`${process.env.FM_STATE_OVERRIDE}/.lock`, `${process.pid}\n`);
+// A native switch re-arms the watcher at once, and OMP starts its first wake as
+// an agent-initiated turn that never emits before_agent_start. The replacement
+// nudge therefore has to land in the replacement session context at switch time,
+// through sendMessage, and nothing may stay staged for a later before_agent_start.
+const switchNudges = () => watcherMessages.filter((entry) => entry.message.customType === "firstmate-sessionstart-nudge");
+async function expectSwitchNudge(label, expectedTotal) {
+  const nudges = switchNudges();
+  if (nudges.length !== expectedTotal) {
+    throw new Error(`${label} did not append exactly one startup instruction (${nudges.length} total): ${JSON.stringify(nudges)}`);
+  }
+  const latest = nudges[nudges.length - 1];
+  if (
+    latest.message.content !== "encoded:session-start:Run `bin/fm-session-start.sh` now, exactly once, before executing any other instructions." ||
+    latest.message.attribution !== "agent" ||
+    latest.message.display !== false ||
+    latest.options?.deliverAs !== "nextTurn" ||
+    latest.options?.triggerTurn !== undefined
+  ) {
+    throw new Error(`${label} startup instruction was not appended as hidden agent context without a turn: ${JSON.stringify(latest)}`);
+  }
+  for (const attempt of [1, 2]) {
+    if (await handlers.get("before_agent_start")({ type: "before_agent_start" }, {}) !== undefined) {
+      throw new Error(`${label} staged its startup instruction for before_agent_start too (attempt ${attempt})`);
+    }
+  }
+}
 await handlers.get("session_switch")({ type: "session_switch", reason: "new" }, extensionContext);
 await waitForWatchCount(1, "in-process OMP /new automatic watcher arm");
-const newStartup = await handlers.get("before_agent_start")({ type: "before_agent_start" }, {});
-if (newStartup?.message?.customType !== "firstmate-sessionstart-nudge" || newStartup.message.attribution !== "agent") {
-  throw new Error(`in-process OMP /new lost its once-only startup instruction: ${JSON.stringify(newStartup)}`);
-}
-if (await handlers.get("before_agent_start")({ type: "before_agent_start" }, {}) !== undefined) {
-  throw new Error("in-process OMP /new repeated its startup instruction");
-}
+await expectSwitchNudge("in-process OMP /new", 1);
+// Regression: a second /new with no before_agent_start in between must still
+// deliver its own nudge because the replacement turn was agent-initiated.
+await handlers.get("session_switch")({ type: "session_switch", reason: "new" }, extensionContext);
+await waitForWatchCount(2, "in-process OMP second /new automatic watcher arm");
+await expectSwitchNudge("in-process OMP second /new", 2);
 await handlers.get("session_switch")({ type: "session_switch", reason: "resume" }, extensionContext);
-await waitForWatchCount(2, "in-process OMP /resume automatic watcher arm");
-const resumeStartup = await handlers.get("before_agent_start")({ type: "before_agent_start" }, {});
-if (resumeStartup?.message?.customType !== "firstmate-sessionstart-nudge" || resumeStartup.message.attribution !== "agent") {
-  throw new Error(`in-process OMP /resume lost its once-only startup instruction: ${JSON.stringify(resumeStartup)}`);
-}
-if (await handlers.get("before_agent_start")({ type: "before_agent_start" }, {}) !== undefined) {
-  throw new Error("in-process OMP /resume repeated its startup instruction");
+await waitForWatchCount(3, "in-process OMP /resume automatic watcher arm");
+await expectSwitchNudge("in-process OMP /resume", 3);
+await handlers.get("session_switch")({ type: "session_switch", reason: "fork" }, extensionContext);
+await waitForWatchCount(4, "in-process OMP /fork automatic watcher arm");
+if (switchNudges().length !== 3 || await handlers.get("before_agent_start")({ type: "before_agent_start" }, {}) !== undefined) {
+  throw new Error("in-process OMP /fork delivered a startup instruction while this session still holds the lock");
 }
+watcherMessages.length = 0;
 
 const signal = new AbortController().signal;
 const stop = await handlers.get("session_stop")({