diff --git a/scripts/bash/check-prerequisites.sh b/scripts/bash/check-prerequisites.sh
index 95e7344d80..3915e7e276 100644
--- a/scripts/bash/check-prerequisites.sh
+++ b/scripts/bash/check-prerequisites.sh
@@ -111,8 +111,11 @@ if $PATHS_ONLY; then
     exit 0
 fi
 
-# Validate branch name
-check_feature_branch "$CURRENT_BRANCH" "$HAS_GIT" || exit 1
+# Validate branch name (skipped when feature.json pins an existing feature dir,
+# matching setup-plan.sh / setup-tasks.sh so the command set stays consistent)
+if ! feature_json_matches_feature_dir "$REPO_ROOT" "$FEATURE_DIR"; then
+    check_feature_branch "$CURRENT_BRANCH" "$HAS_GIT" || exit 1
+fi
 
 # Validate required directories and files
 if [[ ! -d "$FEATURE_DIR" ]]; then
diff --git a/scripts/powershell/check-prerequisites.ps1 b/scripts/powershell/check-prerequisites.ps1
index bcf3aa46c4..074712dffb 100644
--- a/scripts/powershell/check-prerequisites.ps1
+++ b/scripts/powershell/check-prerequisites.ps1
@@ -81,9 +81,12 @@ if ($PathsOnly) {
     exit 0
 }
 
-# Validate branch name
-if (-not (Test-FeatureBranch -Branch $paths.CURRENT_BRANCH -HasGit:$paths.HAS_GIT)) {
-    exit 1
+# Validate branch name (skipped when feature.json pins an existing feature dir,
+# matching setup-plan.ps1 / setup-tasks.ps1 so the command set stays consistent)
+if (-not (Test-FeatureJsonMatchesFeatureDir -RepoRoot $paths.REPO_ROOT -ActiveFeatureDir $paths.FEATURE_DIR)) {
+    if (-not (Test-FeatureBranch -Branch $paths.CURRENT_BRANCH -HasGit $paths.HAS_GIT)) {
+        exit 1
+    }
 }
 
 # Validate required directories and files
diff --git a/tests/test_check_prerequisites_feature_json.py b/tests/test_check_prerequisites_feature_json.py
new file mode 100644
index 0000000000..f1613e0936
--- /dev/null
+++ b/tests/test_check_prerequisites_feature_json.py
@@ -0,0 +1,191 @@
+"""check-prerequisites honors feature.json the same way setup-plan/-tasks do.
+
+Regression guard for the inconsistency where setup-plan.sh / setup-tasks.sh
+skipped the feature-branch check when .specify/feature.json pinned an existing
+feature directory, but check-prerequisites.{sh,ps1} did not — so half the
+spec-kit commands succeeded and half failed on the same branch.
+"""
+
+import json
+import os
+import shutil
+import subprocess
+from pathlib import Path
+
+import pytest
+
+from tests.conftest import requires_bash
+
+PROJECT_ROOT = Path(__file__).resolve().parent.parent
+COMMON_SH = PROJECT_ROOT / "scripts" / "bash" / "common.sh"
+CHECK_SH = PROJECT_ROOT / "scripts" / "bash" / "check-prerequisites.sh"
+COMMON_PS = PROJECT_ROOT / "scripts" / "powershell" / "common.ps1"
+CHECK_PS = PROJECT_ROOT / "scripts" / "powershell" / "check-prerequisites.ps1"
+
+HAS_PWSH = shutil.which("pwsh") is not None
+_POWERSHELL = shutil.which("powershell.exe") or shutil.which("powershell")
+
+
+def _install_bash_scripts(repo: Path) -> None:
+    d = repo / ".specify" / "scripts" / "bash"
+    d.mkdir(parents=True, exist_ok=True)
+    shutil.copy(COMMON_SH, d / "common.sh")
+    shutil.copy(CHECK_SH, d / "check-prerequisites.sh")
+
+
+def _install_ps_scripts(repo: Path) -> None:
+    d = repo / ".specify" / "scripts" / "powershell"
+    d.mkdir(parents=True, exist_ok=True)
+    shutil.copy(COMMON_PS, d / "common.ps1")
+    shutil.copy(CHECK_PS, d / "check-prerequisites.ps1")
+
+
+def _clean_env() -> dict[str, str]:
+    """Strip SPECIFY_* vars so each case relies purely on branch + feature.json."""
+    env = os.environ.copy()
+    for key in list(env):
+        if key.startswith("SPECIFY_"):
+            env.pop(key)
+    return env
+
+
+def _git_init(repo: Path) -> None:
+    subprocess.run(["git", "init", "-q"], cwd=repo, check=True)
+    subprocess.run(["git", "config", "user.email", "test@example.com"], cwd=repo, check=True)
+    subprocess.run(["git", "config", "user.name", "Test User"], cwd=repo, check=True)
+    subprocess.run(["git", "commit", "--allow-empty", "-m", "init", "-q"], cwd=repo, check=True)
+
+
+def _populate_feature(repo: Path, *, with_tasks: bool = False) -> Path:
+    feat = repo / "specs" / "001-tiny-notes-app"
+    feat.mkdir(parents=True, exist_ok=True)
+    (feat / "spec.md").write_text("# spec\n", encoding="utf-8")
+    (feat / "plan.md").write_text("# plan\n", encoding="utf-8")
+    if with_tasks:
+        (feat / "tasks.md").write_text("# tasks\n", encoding="utf-8")
+    return feat
+
+
+def _pin_feature_json(repo: Path, feature_directory: str = "specs/001-tiny-notes-app") -> None:
+    (repo / ".specify" / "feature.json").write_text(
+        json.dumps({"feature_directory": feature_directory}),
+        encoding="utf-8",
+    )
+
+
+@pytest.fixture
+def prereq_repo(tmp_path: Path) -> Path:
+    repo = tmp_path / "proj"
+    repo.mkdir()
+    _git_init(repo)
+    (repo / ".specify").mkdir(exist_ok=True)
+    _install_bash_scripts(repo)
+    _install_ps_scripts(repo)
+    subprocess.run(
+        ["git", "checkout", "-q", "-b", "chore/not-a-feature-branch"], cwd=repo, check=True
+    )
+    return repo
+
+
+def _run_bash(repo: Path, *args: str) -> subprocess.CompletedProcess:
+    script = repo / ".specify" / "scripts" / "bash" / "check-prerequisites.sh"
+    return subprocess.run(
+        ["bash", str(script), *args],
+        cwd=repo,
+        capture_output=True,
+        text=True,
+        check=False,
+        env=_clean_env(),
+    )
+
+
+def _run_ps(repo: Path, *args: str) -> subprocess.CompletedProcess:
+    script = repo / ".specify" / "scripts" / "powershell" / "check-prerequisites.ps1"
+    exe = "pwsh" if HAS_PWSH else _POWERSHELL
+    return subprocess.run(
+        [exe, "-NoProfile", "-File", str(script), *args],
+        cwd=repo,
+        capture_output=True,
+        text=True,
+        check=False,
+        env=_clean_env(),
+    )
+
+
+@requires_bash
+def test_bash_json_passes_custom_branch_when_feature_json_valid(prereq_repo: Path) -> None:
+    _populate_feature(prereq_repo)
+    _pin_feature_json(prereq_repo)
+    result = _run_bash(prereq_repo, "--json")
+    assert result.returncode == 0, result.stderr + result.stdout
+
+
+@requires_bash
+def test_bash_require_tasks_passes_when_feature_json_valid(prereq_repo: Path) -> None:
+    _populate_feature(prereq_repo, with_tasks=True)
+    _pin_feature_json(prereq_repo)
+    result = _run_bash(prereq_repo, "--json", "--require-tasks", "--include-tasks")
+    assert result.returncode == 0, result.stderr + result.stdout
+
+
+@requires_bash
+def test_bash_json_fails_custom_branch_without_feature_json(prereq_repo: Path) -> None:
+    _populate_feature(prereq_repo)
+    result = _run_bash(prereq_repo, "--json")
+    assert result.returncode != 0
+    assert "Not on a feature branch" in result.stderr
+
+
+@requires_bash
+def test_bash_json_enforces_branch_when_feature_json_pins_missing_dir(prereq_repo: Path) -> None:
+    # The bypass must only trigger when feature.json matches an EXISTING dir.
+    # A bogus pin must NOT bypass the branch check.
+    _populate_feature(prereq_repo)
+    _pin_feature_json(prereq_repo, feature_directory="specs/999-does-not-exist")
+    result = _run_bash(prereq_repo, "--json")
+    assert result.returncode != 0
+    assert "Not on a feature branch" in result.stderr
+
+
+@requires_bash
+def test_bash_json_enforces_branch_when_feature_json_malformed(prereq_repo: Path) -> None:
+    # Malformed feature.json must fail safe (enforce the branch check), not bypass it.
+    _populate_feature(prereq_repo)
+    (prereq_repo / ".specify" / "feature.json").write_text("{ not json", encoding="utf-8")
+    result = _run_bash(prereq_repo, "--json")
+    assert result.returncode != 0
+    assert "Not on a feature branch" in result.stderr
+
+
+@requires_bash
+def test_bash_paths_only_always_succeeds(prereq_repo: Path) -> None:
+    # --paths-only performs no validation and must succeed regardless of branch.
+    result = _run_bash(prereq_repo, "--json", "--paths-only")
+    assert result.returncode == 0, result.stderr + result.stdout
+
+
+@pytest.mark.skipif(not (HAS_PWSH or _POWERSHELL), reason="no PowerShell available")
+def test_ps_json_passes_custom_branch_when_feature_json_valid(prereq_repo: Path) -> None:
+    _populate_feature(prereq_repo)
+    _pin_feature_json(prereq_repo)
+    result = _run_ps(prereq_repo, "-Json")
+    assert result.returncode == 0, result.stderr + result.stdout
+
+
+@pytest.mark.skipif(not (HAS_PWSH or _POWERSHELL), reason="no PowerShell available")
+def test_ps_json_fails_custom_branch_without_feature_json(prereq_repo: Path) -> None:
+    _populate_feature(prereq_repo)
+    result = _run_ps(prereq_repo, "-Json")
+    assert result.returncode != 0
+    # Assert the branch check is the failure cause — not the later "feature dir
+    # not found" check, which would also exit 1 and mask a broken guard.
+    assert "Not on a feature branch" in result.stderr
+
+
+@pytest.mark.skipif(not (HAS_PWSH or _POWERSHELL), reason="no PowerShell available")
+def test_ps_json_enforces_branch_when_feature_json_pins_missing_dir(prereq_repo: Path) -> None:
+    _populate_feature(prereq_repo)
+    _pin_feature_json(prereq_repo, feature_directory="specs/999-does-not-exist")
+    result = _run_ps(prereq_repo, "-Json")
+    assert result.returncode != 0
+    assert "Not on a feature branch" in result.stderr