diff --git a/.github/workflows/local-ci.yml b/.github/workflows/local-ci.yml
index 0c5fab515dab..cbc1aeba66f8 100644
--- a/.github/workflows/local-ci.yml
+++ b/.github/workflows/local-ci.yml
@@ -30,6 +30,24 @@ jobs:
       - name: Check fork surface
         if: hashFiles('local/scripts/check_fork_surface.py') != ''
         run: python3 local/scripts/check_fork_surface.py
+      # TODO: switch to `uses: randlee/sc-lint@v1` (operation: setup, pinned
+      # released version) once sc-lint ships prefix patterns + SCB-FEATURE-001
+      # (randlee/sc-lint#603). Until then, build the PR commit from git.
+      - name: Cache sc-lint
+        id: sc-lint-cache
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/bin/sc-lint
+            ~/.cargo/bin/sc-lint-boundary
+          key: sc-lint-bc19f2b-${{ runner.os }}
+      - name: Install sc-lint
+        if: steps.sc-lint-cache.outputs.cache-hit != 'true'
+        run: cargo install --locked --git https://github.com/ehrvs/sc-lint --rev bc19f2b sc-lint sc-lint-boundary
+      - name: sc-lint boundary (fork independence)
+        if: hashFiles('codex-rs/sc-lint.toml') != ''
+        working-directory: codex-rs
+        run: sc-lint lint sc-boundary --rule-filter dependencies
 
   python:
     runs-on: ubuntu-latest
diff --git a/codex-rs/boundaries/codex-local-cli/codex-local-cli.toml b/codex-rs/boundaries/codex-local-cli/codex-local-cli.toml
new file mode 100644
index 000000000000..7ba2bbe72069
--- /dev/null
+++ b/codex-rs/boundaries/codex-local-cli/codex-local-cli.toml
@@ -0,0 +1,37 @@
+boundary_id = "BOUNDARY-CodexLocalCli"
+owner_package = "codex-local-cli"
+owner_crate_path = "codex_local_cli"
+name = "CodexLocalCli"
+
+[public]
+facade = "Homes"
+
+[implementation]
+type = "Homes"
+module = "codex_local_cli"
+visibility = "public"
+constructor = "none"
+
+[composition]
+roots = ["Homes"]
+
+[dependencies]
+allowed_dependents = []
+allowed_dependencies = ["codex-*"]
+allowed_feature_dependencies = []
+forbidden_edges = []
+
+[references]
+scope = "outside_owner_crate"
+forbidden = []
+
+[testing]
+allowed_test_double_paths = []
+forbidden_test_bypasses = []
+
+[enforcement]
+lint_rules = []
+review_gates = ["fork_independence"]
+
+[status]
+state = "concrete_landed"
diff --git a/codex-rs/boundaries/codex-local-models/codex-local-models.toml b/codex-rs/boundaries/codex-local-models/codex-local-models.toml
new file mode 100644
index 000000000000..e26975abc9f1
--- /dev/null
+++ b/codex-rs/boundaries/codex-local-models/codex-local-models.toml
@@ -0,0 +1,37 @@
+boundary_id = "BOUNDARY-CodexLocalModels"
+owner_package = "codex-local-models"
+owner_crate_path = "codex_local_models"
+name = "CodexLocalModels"
+
+[public]
+facade = "Engine"
+
+[implementation]
+type = "Engine"
+module = "codex_local_models"
+visibility = "public"
+constructor = "none"
+
+[composition]
+roots = ["Engine"]
+
+[dependencies]
+allowed_dependents = ["codex-local-cli"]
+allowed_dependencies = ["codex-http-client", "codex-login", "codex-model-provider", "codex-model-provider-info", "codex-models-manager", "codex-protocol"]
+allowed_feature_dependencies = []
+forbidden_edges = []
+
+[references]
+scope = "outside_owner_crate"
+forbidden = []
+
+[testing]
+allowed_test_double_paths = []
+forbidden_test_bypasses = []
+
+[enforcement]
+lint_rules = []
+review_gates = ["fork_independence"]
+
+[status]
+state = "concrete_landed"
diff --git a/codex-rs/boundaries/codex-local-resume/codex-local-resume.toml b/codex-rs/boundaries/codex-local-resume/codex-local-resume.toml
new file mode 100644
index 000000000000..daf1312eeffe
--- /dev/null
+++ b/codex-rs/boundaries/codex-local-resume/codex-local-resume.toml
@@ -0,0 +1,37 @@
+boundary_id = "BOUNDARY-CodexLocalResume"
+owner_package = "codex-local-resume"
+owner_crate_path = "codex_local_resume"
+name = "CodexLocalResume"
+
+[public]
+facade = "sanitize_history"
+
+[implementation]
+type = "sanitize_history"
+module = "codex_local_resume"
+visibility = "public"
+constructor = "none"
+
+[composition]
+roots = ["sanitize_history"]
+
+[dependencies]
+allowed_dependents = ["codex-local-cli"]
+allowed_dependencies = ["codex-core", "codex-protocol", "codex-tui"]
+allowed_feature_dependencies = []
+forbidden_edges = []
+
+[references]
+scope = "outside_owner_crate"
+forbidden = []
+
+[testing]
+allowed_test_double_paths = []
+forbidden_test_bypasses = []
+
+[enforcement]
+lint_rules = []
+review_gates = ["fork_independence"]
+
+[status]
+state = "concrete_landed"
diff --git a/codex-rs/boundaries/planning.toml b/codex-rs/boundaries/planning.toml
new file mode 100644
index 000000000000..7d2e086363b9
--- /dev/null
+++ b/codex-rs/boundaries/planning.toml
@@ -0,0 +1,2 @@
+[planning]
+current_sprint = "1.1"
diff --git a/codex-rs/sc-lint.toml b/codex-rs/sc-lint.toml
new file mode 100644
index 000000000000..6ed47ca44aa1
--- /dev/null
+++ b/codex-rs/sc-lint.toml
@@ -0,0 +1,9 @@
+# Fork-owned. Enforces crate/feature independence between codex-rs/local/* and
+# upstream crates (see boundaries/). Only the dependency rules run, so
+# upstream manifests are not linted.
+[tool.sc-lint]
+minimum_version = "0.4.0"
+
+[[tool.sc-lint.lint]]
+name = "fork-boundary"
+command = ["sc-lint", "lint", "sc-boundary", "--rule-filter", "dependencies"]
diff --git a/local/docs/plan-deltas.md b/local/docs/plan-deltas.md
index 1c0ddeb78af1..030056819161 100644
--- a/local/docs/plan-deltas.md
+++ b/local/docs/plan-deltas.md
@@ -3,7 +3,7 @@
 Where the build differs from the approved plan.
 
 - **GitHub home:** PixelatedMountainStream/codex, with stacked PRs on base `codex-local/main`. The Radiant-Vision-Systems fork is deferred, because org members can't create public repos.
-- **Boundary check:** sc-lint boundary records were replaced by a `cargo metadata` check in `check_fork_surface.py`. sc-lint has no wildcard mode and would need a static list of 161 crates.
+- **Boundary check:** sc-lint enforces crate and feature independence between `codex-rs/local/*` and upstream (`codex-rs/sc-lint.toml`, records in `codex-rs/boundaries/`). It relies on trailing-`*` prefix patterns and SCB-FEATURE-001 from randlee/sc-lint#603, so CI installs a pinned git revision until a release exists. `check_fork_surface.py` only checks that every `codex-local-*` crate has a record.
 - **New hook H8:** in `core/src/tools/router.rs` (splits flattened `ns.name` tool names on a registry miss).
 - **H1:** uses `include!` of upstream `cli/src/main.rs` under `cfg(codex_local)`. `codex-local-cli`'s dependencies must mirror upstream cli's.
 - **H4:** also drops the provider filter for named lookups when registered.
diff --git a/local/fork-surface.toml b/local/fork-surface.toml
index 67b8e0e55f2e..1278b5a0add0 100644
--- a/local/fork-surface.toml
+++ b/local/fork-surface.toml
@@ -11,7 +11,8 @@
 #                             the budget (e.g. Cargo.lock; verify by regeneration).
 #   ignore    list of globs   OPTIONAL extra fork-owned globs, appended to the
 #                             built-in set, which is always ignored: local/**,
-#                             codex-rs/local/**, boundaries/**, .claude/**,
+#                             codex-rs/local/**, boundaries/**,
+#                             codex-rs/boundaries/**, codex-rs/sc-lint.toml, .claude/**,
 #                             .codex/skills/**, .github/workflows/local-*.yml,
 #                             .github/workflows/upstream-sync.yml
 #   [budget]
diff --git a/local/scripts/check_fork_surface.py b/local/scripts/check_fork_surface.py
index 838f6a11325f..6ef18a5aa8b6 100755
--- a/local/scripts/check_fork_surface.py
+++ b/local/scripts/check_fork_surface.py
@@ -4,6 +4,9 @@
 Prints one JSON object {ok, upstream, files[], total_lines, violations[]} and
 exits 0 when ok, 1 on violations, 2 on a tool error (bad config, missing tag).
 The policy schema is documented at the top of local/fork-surface.toml.
+Crate/feature dependency edges are not checked here: sc-lint owns them
+(codex-rs/sc-lint.toml + codex-rs/boundaries/). This script only verifies each
+codex-local-* crate has a boundary record.
 """
 import argparse
 import json
@@ -18,6 +21,8 @@
     "codex-rs/local/**",
     "local/**",
     "boundaries/**",
+    "codex-rs/boundaries/**",
+    "codex-rs/sc-lint.toml",
     ".claude/**",
     ".codex/skills/**",
     ".github/workflows/local-*.yml",
@@ -63,35 +68,22 @@ def resolve_ref(root, tag):
     raise RuntimeError(f"upstream ref not found: {tag} (also tried upstream/{tag})")
 
 
-def local_dependency_violations(root):
-    """No crate outside codex-local-* may depend on codex-local-*, and only
-    codex-local-cli may depend on another local crate (it is the only root).
+def boundary_record_violations(root):
+    """Every codex-local-* crate under codex-rs/local/ needs a boundary record
+    directory codex-rs/boundaries/<name>/ with at least one .toml file.
 
-    sc-lint has no wildcard/default-allow mode (allowed_dependencies is
-    mandatory, so local crates could not depend on arbitrary upstream crates),
-    so this rule is enforced here, generically, with no crate lists.
+    The dependency/feature edges themselves are enforced by sc-lint
+    (codex-rs/sc-lint.toml, run in local-ci); this only guards coverage.
     """
-    ws = Path(root) / "codex-rs"
-    if not (ws / "Cargo.toml").exists():
-        return []
-    r = subprocess.run(["cargo", "metadata", "--no-deps", "--format-version", "1"],
-                       cwd=ws, capture_output=True, text=True)
-    if r.returncode:
-        raise RuntimeError("cargo metadata: " + r.stderr.strip()[-300:])
+    local = Path(root) / "codex-rs" / "local"
     out = []
-    for pkg in json.loads(r.stdout)["packages"]:
-        name = pkg["name"]
-        for dep in pkg["dependencies"]:
-            if not dep["name"].startswith("codex-local-"):
-                continue
-            if not name.startswith("codex-local-"):
-                out.append({"kind": "upstream_depends_on_local", "crate": name,
-                            "dependency": dep["name"]})
-            elif name != "codex-local-cli" and dep["name"] != name:
-                out.append({"kind": "local_not_callable_from_cli_only", "crate": name,
-                            "dependency": dep["name"]})
-            elif name == "codex-local-cli" and dep["name"] == name:
-                continue
+    for manifest in sorted(local.glob("*/Cargo.toml")):
+        name = tomllib.loads(manifest.read_text()).get("package", {}).get("name", "")
+        if not name.startswith("codex-local-"):
+            continue
+        rec = Path(root) / "codex-rs" / "boundaries" / name
+        if not any(rec.glob("*.toml")):
+            out.append({"kind": "missing_boundary_record", "crate": name})
     return out
 
 
@@ -123,7 +115,7 @@ def check(root):
         violations.append({"kind": "over_line_budget", "lines": total, "max": max_lines})
     if max_files is not None and len(files) > max_files:
         violations.append({"kind": "over_file_budget", "files": len(files), "max": max_files})
-    violations += local_dependency_violations(root)
+    violations += boundary_record_violations(root)
     return {
         "ok": not violations,
         "upstream": tag,
diff --git a/local/scripts/sync_upstream.py b/local/scripts/sync_upstream.py
index f6dd267504e2..72d73f8387fc 100755
--- a/local/scripts/sync_upstream.py
+++ b/local/scripts/sync_upstream.py
@@ -120,9 +120,11 @@ def classify(path, allow, generated):
 
 
 def unmerged(root):
-    out = git(root, "diff", "--name-only", "--diff-filter=U").stdout
+    # index stage entries are the authoritative record of unmerged paths
+    out = git(root, "ls-files", "-u", "-z").stdout
+    paths = sorted({e.split("\t", 1)[1] for e in out.split("\0") if "\t" in e})
     allow, generated = load_policy(root)
-    return [{"path": p, "kind": classify(p, allow, generated)} for p in out.splitlines() if p]
+    return [{"path": p, "kind": classify(p, allow, generated)} for p in paths]
 
 
 def conflict_result(step, root):
diff --git a/local/tests/test_sync_upstream.py b/local/tests/test_sync_upstream.py
index 4b5a9b3ab2a0..97b2ef27ffff 100644
--- a/local/tests/test_sync_upstream.py
+++ b/local/tests/test_sync_upstream.py
@@ -1,5 +1,6 @@
 import contextlib
 import io
+import os
 import json
 import subprocess
 import sys
@@ -14,8 +15,18 @@
 KEYS = {"ok", "step", "conflicts", "build_errors", "test_failures", "surface_violations", "next_action"}
 
 
-def git(cwd, *a):
-    subprocess.run(["git", "-c", "user.name=t", "-c", "user.email=t@t", *a], cwd=cwd, check=True, capture_output=True)
+HERMETIC = ["-c", "user.name=t", "-c", "user.email=t@t", "-c", "init.defaultBranch=main",
+            "-c", "commit.gpgsign=false", "-c", "tag.gpgsign=false"]
+
+
+def _env():
+    env = {k: v for k, v in os.environ.items() if not k.startswith("GIT_")}
+    env.update(GIT_CONFIG_GLOBAL=os.devnull, GIT_CONFIG_NOSYSTEM="1")
+    return env
+
+
+def git(cwd, *a, check=True):
+    return subprocess.run(["git", *HERMETIC, *a], cwd=cwd, check=check, capture_output=True, text=True, env=_env())
 
 
 def run_cli(root, *args):
@@ -78,7 +89,8 @@ def test_conflicts_clean_and_escalate(self):
         git(self.work, "add", "z.rs"); git(self.work, "commit", "-qm", "1")
         git(self.work, "checkout", "-q", "-b", "m2", "m1~1"); (self.work / "z.rs").write_text("2")
         git(self.work, "add", "z.rs"); git(self.work, "commit", "-qm", "2")
-        subprocess.run(["git", "merge", "m1"], cwd=self.work, capture_output=True)
+        git(self.work, "merge", "m1", check=False)  # expected to conflict
+        self.assertTrue(git(self.work, "ls-files", "-u").stdout.strip(), "setup produced no conflict")
         code, out = run_cli(self.work, "conflicts")
         self.assertEqual(code, 2)
         self.assertEqual(out["conflicts"], [{"path": "z.rs", "kind": "other"}])