diff --git a/backend/apps/agents/browser/browser_agent.py b/backend/apps/agents/browser/browser_agent.py
index 38398f4c..94a9df82 100644
--- a/backend/apps/agents/browser/browser_agent.py
+++ b/backend/apps/agents/browser/browser_agent.py
@@ -321,6 +321,28 @@ async def execute_browser_tool(
     return result
 
 
+async def p_learn_write_recipe(execute_tool, browser_id: str, tab_id: str, current_url: str, payload: str) -> None:
+    """After a receipt-VERIFIED DOM write, distill the site's own write route into a replayable
+    recipe so the NEXT write on this host can skip the DOM (the repeated-write tier). Inline +
+    bounded (the card is still alive here; a fire-and-forget task would race the finish teardown)
+    and fully fail-open: no routes / no payload leaf / any error just means no recipe learned, and
+    the DOM path stays the default. Gated OFF until soaked (OSW_WRITE_RECIPES=1)."""
+    if os.environ.get("OSW_WRITE_RECIPES", "0") == "0":
+        return
+    try:
+        from backend.apps.agents.browser import browser_write_recipes, browser_skills
+        host = browser_skills.host_of(current_url or "")
+        if not host or len(payload or "") < 4:
+            return
+        listed = await asyncio.wait_for(
+            execute_tool("BrowserListRoutes", {"writes": True}, browser_id, tab_id), timeout=4.0)
+        routes = listed.get("routes") if isinstance(listed, dict) else None
+        if routes and browser_write_recipes.learn_recipe(host, payload, routes):
+            logger.info(f"[write-recipe] learned a replayable {host} write from a verified DOM send")
+    except Exception:
+        pass
+
+
 def p_extract_domain(url: str) -> str | None:
     """Extract the apex domain from a URL (acme-corp.notion.so → notion.so).
     Returns None for non-http URLs."""
@@ -1414,6 +1436,7 @@ async def run_browser_agent(
                 done_called = True
                 done_success = True
                 p_aux_c, p_aux_m = await p_get_aux_client()
+                await p_learn_write_recipe(execute_browser_tool, browser_id, tab_id, current_url, p_script["payload"])
                 done_message = (await compose_send_confirmation(p_aux_c, p_aux_m, task, p_script["payload"])
                                 or f'Done, I sent "{p_script["payload"]}" for you.')
             else:
@@ -2163,6 +2186,7 @@ async def run_browser_agent(
                                 done_called = True
                                 done_success = True
                                 p_payload = browser_batch_replay.send_payload_from_log(action_log, task)
+                                await p_learn_write_recipe(execute_browser_tool, browser_id, tab_id, current_url, p_payload)
                                 p_aux_c, p_aux_m = await p_get_aux_client()
                                 p_nice = (await compose_send_confirmation(p_aux_c, p_aux_m, task, p_payload)
                                           if p_payload else "")
@@ -2256,6 +2280,7 @@ async def run_browser_agent(
                             if p_cs.get("sent"):
                                 done_called = True
                                 done_success = True
+                                await p_learn_write_recipe(execute_browser_tool, browser_id, tab_id, current_url, composer_committed_payload)
                                 p_aux_c, p_aux_m = await p_get_aux_client()
                                 done_message = (await compose_send_confirmation(
                                     p_aux_c, p_aux_m, task, composer_committed_payload)
diff --git a/backend/apps/agents/browser/browser_write_recipes.py b/backend/apps/agents/browser/browser_write_recipes.py
new file mode 100644
index 00000000..ca2c8856
--- /dev/null
+++ b/backend/apps/agents/browser/browser_write_recipes.py
@@ -0,0 +1,232 @@
+"""Learn-on-first-write, replay-on-repeat: the repeated-write half of the API-first tier.
+
+The first write on a site is unavoidably a DOM drive (a route can only be captured after the
+site's own UI fires it, proven live in the V.8 X soak). But the moment a DOM write SUCCEEDS with
+a verified receipt, the mutating route the page fired is a complete recipe: method + URL (with
+its live queryId) + body, with the user's payload sitting in one JSON leaf. This module persists
+that recipe with the payload slot replaced by a sentinel, and replays it with a NEW payload on
+the next write to the same site, skipping the DOM entirely.
+
+SAFETY (documented in SECURITY.md):
+- A recipe is learned ONLY from a receipt-verified successful write the user's own task performed,
+  so its provenance satisfies the captured-route wall (the site's UI genuinely fired it); replay
+  seeds route_write's captured set from the recipe itself.
+- Secret-shaped string leaves in the stored body are redacted at learn time (payload slot
+  excepted); cookies/headers are never stored (route_write borrows them live per call).
+- Same-origin + OSW_ROUTE_WRITE flag + typed fail-open outcomes all still apply at replay.
+- Staleness self-heals: a recipe that misses MAX_MISSES times is dropped, and the next
+  successful DOM write learns a fresh one (queryId rotation just re-learns).
+"""
+
+import json
+import logging
+import os
+import re
+import time
+from typing import Any, Dict, List, Optional
+
+from pydantic import BaseModel, ConfigDict
+from typeguard import typechecked
+
+logger = logging.getLogger(__name__)
+
+SENTINEL = "__OSW_PAYLOAD__"
+P_MIN_PAYLOAD_CHARS = 4
+P_MAX_BODY_CHARS = 32768
+MAX_MISSES = 3
+P_MAX_RECIPES_ON_DISK = 200
+
+# Same secret heuristics as the electron capture (cdp-routes.js), ported so a token-shaped
+# body value can never be persisted; over-redacting is the safe direction.
+P_TOKEN_PREFIX = re.compile(r"^(sk-|ghp_|gho_|pk_|xox[bap]-|AIza|eyJ|Bearer )")
+
+
+@typechecked
+def looks_secret_value(v: str) -> bool:
+    if not v:
+        return False
+    if P_TOKEN_PREFIX.match(v):
+        return True
+    return len(v) >= 20 and bool(re.search(r"[A-Za-z]", v)) and bool(re.search(r"[0-9]", v)) and not re.search(r"\s", v)
+
+
+class WriteRecipe(BaseModel):
+    """One site's proven write call, payload slot replaced by the sentinel."""
+
+    model_config = ConfigDict(validate_assignment=True)
+
+    host: str
+    method: str
+    url_template: str
+    url: str
+    body_template: str
+    payload_path: str
+    learned_at: float
+    wins: int = 0
+    misses: int = 0
+
+
+@typechecked
+def p_dir() -> str:
+    from backend.config.paths import DATA_ROOT
+    d = os.path.join(DATA_ROOT, "browser_write_recipes")
+    os.makedirs(d, mode=0o700, exist_ok=True)
+    return d
+
+
+@typechecked
+def p_path(host: str) -> str:
+    safe = re.sub(r"[^a-z0-9.-]", "_", host.lower())
+    return os.path.join(p_dir(), f"{safe}.json")
+
+
+@typechecked
+def recipe_for(host: str) -> Optional[WriteRecipe]:
+    """The persisted recipe for this host, or None. Corrupt files read as None (fail-open)."""
+    try:
+        with open(p_path(host)) as f:
+            return WriteRecipe(**json.load(f))
+    except Exception:
+        return None
+
+
+@typechecked
+def save_recipe(recipe: WriteRecipe) -> None:
+    """Atomic write, browser_skills pattern; cap the directory so it can't grow unbounded."""
+    try:
+        d = p_dir()
+        entries = sorted(os.listdir(d), key=lambda f: os.path.getmtime(os.path.join(d, f)))
+        while len(entries) >= P_MAX_RECIPES_ON_DISK:
+            os.remove(os.path.join(d, entries.pop(0)))
+        tmp = p_path(recipe.host) + ".tmp"
+        with open(tmp, "w") as f:
+            json.dump(recipe.model_dump(mode="json"), f)
+        os.replace(tmp, p_path(recipe.host))
+    except Exception as e:
+        logger.info(f"[write-recipe] save failed for {recipe.host}: {e}")
+
+
+@typechecked
+def drop_recipe(host: str) -> None:
+    try:
+        os.remove(p_path(host))
+    except OSError:
+        pass
+
+
+@typechecked
+def p_find_payload_leaf(obj: Any, payload: str, path: str = "$") -> Optional[str]:
+    """JSON path of the leaf whose string value EQUALS the payload (exact, not substring:
+    a substring hit means the site wrapped it and blind substitution would corrupt)."""
+    if isinstance(obj, str):
+        return path if obj == payload else None
+    if isinstance(obj, dict):
+        for k, v in obj.items():
+            hit = p_find_payload_leaf(v, payload, f"{path}.{k}")
+            if hit:
+                return hit
+        return None
+    if isinstance(obj, list):
+        for i, v in enumerate(obj):
+            hit = p_find_payload_leaf(v, payload, f"{path}[{i}]")
+            if hit:
+                return hit
+    return None
+
+
+@typechecked
+def p_transform_leaves(obj: Any, payload: str) -> Any:
+    """Copy with the payload leaf swapped for the sentinel and secret-shaped strings redacted."""
+    if isinstance(obj, str):
+        if obj == payload:
+            return SENTINEL
+        return "<redacted>" if looks_secret_value(obj) else obj
+    if isinstance(obj, dict):
+        return {k: p_transform_leaves(v, payload) for k, v in obj.items()}
+    if isinstance(obj, list):
+        return [p_transform_leaves(v, payload) for v in obj]
+    return obj
+
+
+@typechecked
+def learn_recipe(host: str, payload: str, routes: List[Dict[str, Any]]) -> Optional[WriteRecipe]:
+    """Distill a recipe from the captured mutating routes of a JUST-verified write. Returns the
+    saved recipe, or None when no route's body carries the payload as an exact string leaf
+    (then there is nothing provably replayable, so nothing is stored)."""
+    if len(payload or "") < P_MIN_PAYLOAD_CHARS:
+        return None
+    for r in routes:
+        body = str(r.get("lastBody") or "")
+        method = str(r.get("method") or "").upper()
+        if not body or len(body) > P_MAX_BODY_CHARS or method in ("GET", "HEAD"):
+            continue
+        try:
+            parsed = json.loads(body)
+        except (json.JSONDecodeError, ValueError):
+            continue
+        slot = p_find_payload_leaf(parsed, payload)
+        if not slot:
+            continue
+        recipe = WriteRecipe(
+            host=host, method=method,
+            url_template=str(r.get("template") or ""),
+            url=str(r.get("example") or r.get("template") or ""),
+            body_template=json.dumps(p_transform_leaves(parsed, payload)),
+            payload_path=slot, learned_at=time.time(),
+        )
+        save_recipe(recipe)
+        logger.info(f"[write-recipe] learned {host} {method} {recipe.url_template[:80]} slot={slot}")
+        return recipe
+    return None
+
+
+@typechecked
+def build_body(recipe: WriteRecipe, payload: str) -> Optional[Dict[str, Any]]:
+    """The recipe body with the NEW payload in the slot; None when the template holds no
+    sentinel (corrupt or hand-edited = do not replay) or redacted leaves the site requires."""
+    if SENTINEL not in recipe.body_template:
+        return None
+    try:
+        parsed = json.loads(recipe.body_template)
+    except (json.JSONDecodeError, ValueError):
+        return None
+
+    def p_sub(obj: Any) -> Any:
+        if isinstance(obj, str):
+            return payload if obj == SENTINEL else obj
+        if isinstance(obj, dict):
+            return {k: p_sub(v) for k, v in obj.items()}
+        if isinstance(obj, list):
+            return [p_sub(v) for v in obj]
+        return obj
+
+    out = p_sub(parsed)
+    return out if isinstance(out, dict) else None
+
+
+@typechecked
+async def replay_recipe(recipe: WriteRecipe, payload: str, origin: str) -> Dict[str, Any]:
+    """Replay the recipe with a new payload via route_write (same-origin + flag + live-borrowed
+    cookies all enforced there). The recipe IS the captured provenance: it was learned from a
+    route the site's UI fired during a receipt-verified write, so it seeds the captured set.
+    Returns {ok, receipt|error}; a miss bumps the staleness counter and MAX_MISSES drops it."""
+    from backend.apps.agents.browser import route_write
+    body = build_body(recipe, payload)
+    if body is None:
+        drop_recipe(recipe.host)
+        return {"ok": False, "error": "recipe template unusable; dropped"}
+    captured = [route_write.CapturedRoute(method=recipe.method, template=recipe.url_template)]
+    import asyncio
+    out = await asyncio.to_thread(
+        route_write.replay_write, recipe.method, recipe.url, body, origin, captured)
+    if out.ok:
+        recipe.wins += 1
+        save_recipe(recipe)
+        return {"ok": True, "receipt": out.receipt, "latency_ms": out.latency_ms}
+    recipe.misses += 1
+    if recipe.misses >= MAX_MISSES:
+        drop_recipe(recipe.host)
+        logger.info(f"[write-recipe] {recipe.host} dropped after {recipe.misses} misses (stale; next DOM win re-learns)")
+    else:
+        save_recipe(recipe)
+    return {"ok": False, "error": out.error}
diff --git a/backend/tests/test_browser_write_recipes.py b/backend/tests/test_browser_write_recipes.py
new file mode 100644
index 00000000..f76e970e
--- /dev/null
+++ b/backend/tests/test_browser_write_recipes.py
@@ -0,0 +1,97 @@
+"""Unit tests for the learn-on-first-write / replay-on-repeat recipe module.
+Network mocked at route_write.issue_request; disk redirected to tmp_path."""
+
+import json
+from typing import Any, Dict
+
+import pytest
+
+from backend.apps.agents.browser import browser_write_recipes as wr
+from backend.apps.agents.browser import route_write
+
+
+@pytest.fixture(autouse=True)
+def recipes_tmp(tmp_path, monkeypatch):
+    monkeypatch.setattr(wr, "p_dir", lambda: str(tmp_path))
+
+
+P_X_BODY = {
+    "variables": {"tweet_text": "hello from the test", "dark_request": False,
+                  "media": {"media_entities": [], "possibly_sensitive": False}},
+    "features": {"tweetypie_unmention_optimization_enabled": True, "longform_notetweets_consumption_enabled": True},
+    "queryId": "AbCdEf123456",
+}
+
+
+def p_routes(body: Dict[str, Any]) -> list:
+    return [
+        {"method": "GET", "template": "https://x.com/i/api/graphql/{id}/HomeTimeline", "example": "", "lastBody": ""},
+        {"method": "POST", "template": "https://x.com/i/api/graphql/{id}/CreateTweet",
+         "example": "https://x.com/i/api/graphql/AbCdEf123456/CreateTweet", "lastBody": json.dumps(body)},
+    ]
+
+
+def test_learn_finds_payload_slot_and_saves():
+    r = wr.learn_recipe("x.com", "hello from the test", p_routes(P_X_BODY))
+    assert r is not None
+    assert r.payload_path == "$.variables.tweet_text"
+    assert wr.SENTINEL in r.body_template
+    assert "hello from the test" not in r.body_template
+    assert wr.recipe_for("x.com") is not None
+
+
+def test_learn_refuses_substring_and_short_payloads():
+    body = {"variables": {"tweet_text": "prefix hello from the test suffix"}}
+    assert wr.learn_recipe("x.com", "hello from the test", p_routes(body)) is None
+    assert wr.learn_recipe("x.com", "hi", p_routes(P_X_BODY)) is None
+
+
+def test_learn_redacts_secret_leaves_but_keeps_structure():
+    body = {"variables": {"tweet_text": "hello from the test"}, "csrfish": "a1B2c3D4e5F6g7H8i9J0kk"}
+    r = wr.learn_recipe("x.com", "hello from the test", p_routes(body))
+    parsed = json.loads(r.body_template)
+    assert parsed["csrfish"] == "<redacted>"
+    assert parsed["variables"]["tweet_text"] == wr.SENTINEL
+
+
+def test_build_body_substitutes_new_payload_only():
+    r = wr.learn_recipe("x.com", "hello from the test", p_routes(P_X_BODY))
+    body = wr.build_body(r, "a brand new tweet")
+    assert body["variables"]["tweet_text"] == "a brand new tweet"
+    assert body["queryId"] == "AbCdEf123456"
+    r.body_template = json.dumps({"variables": {"tweet_text": "no sentinel here"}})
+    assert wr.build_body(r, "x") is None
+
+
+@pytest.mark.asyncio
+async def test_replay_ok_bumps_wins_and_returns_receipt(monkeypatch):
+    monkeypatch.setenv("OSW_ROUTE_WRITE", "1")
+    r = wr.learn_recipe("x.com", "hello from the test", p_routes(P_X_BODY))
+    monkeypatch.setattr(route_write, "get_session", lambda d: ("auth=1; ct0=abc", "UA"))
+    monkeypatch.setattr(route_write, "issue_request",
+                        lambda m, u, b, h: (200, json.dumps({"data": {"rest_id": "999"}})))
+    out = await wr.replay_recipe(r, "new text", "https://x.com")
+    assert out["ok"] is True and out["receipt"] == "999"
+    assert wr.recipe_for("x.com").wins == 1
+
+
+@pytest.mark.asyncio
+async def test_replay_miss_bumps_and_drops_after_cap(monkeypatch):
+    monkeypatch.setenv("OSW_ROUTE_WRITE", "1")
+    wr.learn_recipe("x.com", "hello from the test", p_routes(P_X_BODY))
+    monkeypatch.setattr(route_write, "get_session", lambda d: ("auth=1", "UA"))
+    monkeypatch.setattr(route_write, "issue_request", lambda m, u, b, h: (404, "gone"))
+    for i in range(wr.MAX_MISSES):
+        r = wr.recipe_for("x.com")
+        assert r is not None, f"recipe gone before miss {i + 1}"
+        out = await wr.replay_recipe(r, "t", "https://x.com")
+        assert out["ok"] is False
+    assert wr.recipe_for("x.com") is None  # stale recipe self-evicted
+
+
+@pytest.mark.asyncio
+async def test_replay_respects_flag_off(monkeypatch):
+    monkeypatch.delenv("OSW_ROUTE_WRITE", raising=False)
+    r = wr.learn_recipe("x.com", "hello from the test", p_routes(P_X_BODY))
+    out = await wr.replay_recipe(r, "t", "https://x.com")
+    assert out["ok"] is False and "disarmed" in out["error"]
diff --git a/electron/cdp-routes.js b/electron/cdp-routes.js
index ada451ab..96c77e81 100644
--- a/electron/cdp-routes.js
+++ b/electron/cdp-routes.js
@@ -95,9 +95,32 @@ function routeKey(method, template) {
   return String(method || 'GET').toUpperCase() + ' ' + template;
 }
 
+// The mutating body WITH values, but secret-shaped string leaves redacted (belt; the backend
+// recipe learner redacts again). Only JSON, capped: a write recipe needs the real body (the user's
+// payload sits in one leaf), which bodyShape (types only) can't provide. Non-JSON / oversized = null.
+const MAX_BODY_CHARS = 65536;
+
+function redactBodyValues(postData) {
+  if (!postData || postData.length > MAX_BODY_CHARS) return null;
+  try {
+    const walk = (v) =>
+      typeof v === 'string'
+        ? (looksSecretValue(v) ? '<redacted>' : v)
+        : Array.isArray(v)
+          ? v.map(walk)
+          : v && typeof v === 'object'
+            ? Object.fromEntries(Object.keys(v).map((k) => [k, walk(v[k])]))
+            : v;
+    return JSON.stringify(walk(JSON.parse(postData)));
+  } catch {
+    return null;
+  }
+}
+
 function makeRouteEntry(request, resourceType) {
   const method = String(request.method || 'GET').toUpperCase();
   const template = templateUrl(request.url);
+  const safe = isSafeMethod(method);
   return {
     method,
     template,
@@ -105,7 +128,9 @@ function makeRouteEntry(request, resourceType) {
     resourceType,
     headers: redactHeaders(request.headers),
     bodyShape: bodyShape(request.postData),
-    safe: isSafeMethod(method),
+    // Only mutating routes carry a replayable body; a GET's body (if any) is never a write recipe.
+    lastBody: safe ? null : redactBodyValues(request.postData),
+    safe,
     hits: 1,
     lastSeen: Date.now(),
   };
@@ -123,6 +148,9 @@ function recordRoute(routesMap, request, resourceType, now = Date.now()) {
   if (existing) {
     existing.hits += 1;
     existing.lastSeen = now;
+    // Refresh the body so a later replay learns from the FRESHEST call (queryId/token rotation
+    // lives in the URL/headers, but a stale body could hold an old nonce); keep the latest.
+    if (entry.lastBody) existing.lastBody = entry.lastBody;
   } else {
     routesMap.set(key, entry);
     if (routesMap.size > MAX_ROUTES_PER_WC) {
diff --git a/electron/cdp-routes.test.js b/electron/cdp-routes.test.js
index 2c3362e4..56bbe621 100644
--- a/electron/cdp-routes.test.js
+++ b/electron/cdp-routes.test.js
@@ -136,3 +136,30 @@ test('makeRouteEntry carries a redacted example url', () => {
   assert.ok(e.example.includes('redacted'));
   assert.ok(!e.example.includes('secretAbc123Long'));
 });
+
+test('makeRouteEntry: mutating route keeps a body, GET does not, secrets redacted', () => {
+  const post = R.makeRouteEntry({
+    method: 'POST',
+    url: 'https://x.com/i/api/graphql/AbC123/CreateTweet',
+    headers: { 'x-csrf-token': 'ct0secret' },
+    postData: JSON.stringify({ variables: { tweet_text: 'hello world' }, authToken: 'aB3xK9mQ2pL7wR4tY8nZ' }),
+  }, 'Fetch');
+  assert.equal(post.safe, false);
+  const body = JSON.parse(post.lastBody);
+  assert.equal(body.variables.tweet_text, 'hello world');      // payload survives
+  assert.equal(body.authToken, '<redacted>');                  // secret leaf redacted
+  assert.equal(post.headers['x-csrf-token'], '<redacted>');    // header redacted
+
+  const get = R.makeRouteEntry({ method: 'GET', url: 'https://x.com/i/api/graphql/AbC123/Home', headers: {}, postData: '' }, 'XHR');
+  assert.equal(get.lastBody, null);                            // no body on a safe route
+});
+
+test('recordRoute: repeat write refreshes lastBody to the freshest call', () => {
+  const m = new Map();
+  const mk = (text) => ({ method: 'POST', url: 'https://x.com/i/api/graphql/AbC/CreateTweet', headers: {}, postData: JSON.stringify({ variables: { tweet_text: text } }) });
+  R.recordRoute(m, mk('first'), 'Fetch');
+  R.recordRoute(m, mk('second'), 'Fetch');
+  const entry = [...m.values()][0];
+  assert.equal(entry.hits, 2);
+  assert.equal(JSON.parse(entry.lastBody).variables.tweet_text, 'second');
+});