diff --git a/docs/operating.md b/docs/operating.md
index 27c4e20..2759920 100644
--- a/docs/operating.md
+++ b/docs/operating.md
@@ -201,6 +201,15 @@ profile file, an oversized or malformed file, or an unreadable `defaultProfile`
 all end in `profile_invalid` before anything is launched. Only a catalog with no
 `cortex/qa-profiles.json` file at all uses the placeholder `nan` route.
 
+Neither command accepts a catalog root reached through a symlink: every path
+component must be a real directory, and `qa setup` refuses to create a missing
+tree. This is a strict policy, not a bug to route around, because the profile and
+the shadow scan have to address the same bytes the run reads. On macOS that
+includes the system temporary directory: `/tmp` is a symlink to `/private/tmp`, so
+a catalog under `/tmp/...` is refused until it is addressed through its canonical
+`/private/tmp/...` path (`cd` into it and use `pwd -P`).
+
+
 ## Walk the QA fleet end to end
 
 The showcase path (#286): from a fresh directory, install from a release, configure a
diff --git a/internal/cli/qa_test.go b/internal/cli/qa_test.go
index f7a3578..66f476e 100644
--- a/internal/cli/qa_test.go
+++ b/internal/cli/qa_test.go
@@ -310,8 +310,49 @@ func TestQARunHonorsRouteProfileFromCatalog(t *testing.T) {
 	}
 }
 
+// TestQASetupAndRunAgreeOnARelativeCatalog reproduces the issue #324 example
+// through the public CLI: setup and run both take the same non-absolute catalog
+// path from one directory, so the run must use the profile setup wrote there
+// instead of ignoring it. The catalog is a disposable copy.
+func TestQASetupAndRunAgreeOnARelativeCatalog(t *testing.T) {
+	args := roleReportFixture(t, qarole.RequirementsAnalyst)
+	cwd := must(os.Getwd())
+	if err := os.CopyFS(filepath.Join(cwd, "catalog"), os.DirFS(qaCatalogArgument(args))); err != nil {
+		t.Fatalf("disposable catalog copy = %v", err)
+	}
+
+	stdout, stderr := &bytes.Buffer{}, &bytes.Buffer{}
+	setup := []string{"qa", "setup", "--catalog", "catalog", "--provider", "nan", "--model", "glm5.3", "--effort", "high"}
+	if code := Run(context.Background(), setup, stdout, stderr, nil); code != exitOK {
+		t.Fatalf("relative qa setup exit = %d stderr = %q", code, stderr.String())
+	}
+
+	stdout.Reset()
+	stderr.Reset()
+	run := []string{"qa", "run", "--role", "requirements-analyst", "--request", "requirements.txt", "--catalog", "catalog"}
+	if code := Run(context.Background(), run, stdout, stderr, nil); code != exitOK || stdout.String() != fixtureReport+"\n" || stderr.Len() != 0 {
+		t.Fatalf("relative qa run = %d stdout %q stderr %q", code, stdout.String(), stderr.String())
+	}
+	frame := must(os.ReadFile("qa-report-frame"))
+	for _, want := range []string{"route_profile qa-fleet", "route_model glm5.3", "route_backend pi"} {
+		if !bytes.Contains(frame, []byte(want)) {
+			t.Fatalf("relative catalog run ignored the profile setup wrote: frame lost %q", want)
+		}
+	}
+}
+
+// qaSetupCatalogFixture returns a disposable catalog root that already carries
+// catalog.json: `qa setup` refuses to create the tree (#324), so a fixture that
+// expects a written profile must look like a catalog `qa run` could load.
+func qaSetupCatalogFixture(t *testing.T) string {
+	t.Helper()
+	root := must(filepath.EvalSymlinks(t.TempDir()))
+	mustOK(os.WriteFile(filepath.Join(root, "catalog.json"), []byte("{}\n"), 0o600))
+	return root
+}
+
 func TestQASetupWritesProfileForAllRoles(t *testing.T) {
-	catalog := t.TempDir()
+	catalog := qaSetupCatalogFixture(t)
 	original := qaPiResolver
 	qaPiResolver = fixturePi{must(os.Executable())}
 	t.Cleanup(func() { qaPiResolver = original })
@@ -349,8 +390,62 @@ func TestQASetupWritesProfileForAllRoles(t *testing.T) {
 	}
 }
 
+// refusingPi fails if anything asks it to resolve a runtime binary. qa setup
+// must validate the catalog root before it probes model availability (#324),
+// so a refusal at the catalog stage proves the probe never ran.
+type refusingPi struct{ calls int }
+
+func (resolver *refusingPi) Resolve(context.Context) (string, error) {
+	resolver.calls++
+	return "", fmt.Errorf("qa setup probed models before validating the catalog root")
+}
+
+// TestQASetupRefusesCatalogRootsQaRunCouldNotLoad pins the setup half of the
+// source-agreement rule (#324): setup writes the profile only into a catalog
+// root `qa run` can load, and it never creates the tree. A typo therefore fails
+// loudly instead of writing a profile no run would ever read.
+func TestQASetupRefusesCatalogRootsQaRunCouldNotLoad(t *testing.T) {
+	root := must(filepath.EvalSymlinks(t.TempDir()))
+	mustOK(os.Mkdir(filepath.Join(root, "empty"), 0o700))
+	linked := must(filepath.EvalSymlinks(t.TempDir()))
+	mustOK(os.WriteFile(filepath.Join(linked, "catalog.json"), []byte("{}\n"), 0o600))
+	mustOK(os.Symlink(linked, filepath.Join(root, "linked-catalog")))
+	t.Chdir(root)
+	for _, testCase := range []struct{ name, catalog, reason string }{
+		{name: "absent root", catalog: "typo-catalog", reason: "missing"},
+		{name: "directory without catalog.json", catalog: "empty", reason: "catalog_json_missing"},
+		{name: "symlinked root", catalog: "linked-catalog", reason: "unusable"},
+	} {
+		t.Run(testCase.name, func(t *testing.T) {
+			resolver := &refusingPi{}
+			original := qaPiResolver
+			qaPiResolver = resolver
+			t.Cleanup(func() { qaPiResolver = original })
+
+			stdout, stderr := &bytes.Buffer{}, &bytes.Buffer{}
+			args := []string{"qa", "setup", "--catalog", testCase.catalog, "--provider", "openai-codex", "--model", "gpt-5.6-terra"}
+			code := Run(context.Background(), args, stdout, stderr, nil)
+			want := "error=setup_failed\nstage=catalog expected=catalog root containing catalog.json catalog_reason=" + testCase.reason + " next_check=cortex qa --help\n"
+			if code != exitFailure || stdout.Len() != 0 || stderr.String() != want {
+				t.Fatalf("qa setup = %d stdout %q stderr %q, want %q", code, stdout.String(), stderr.String(), want)
+			}
+			if resolver.calls != 0 {
+				t.Fatalf("qa setup resolved the runtime %d times before validating the catalog root", resolver.calls)
+			}
+			if _, err := os.Stat(filepath.Join(root, testCase.catalog, "cortex")); !os.IsNotExist(err) {
+				t.Fatalf("qa setup wrote a profile tree under %q after refusing the catalog root", testCase.catalog)
+			}
+			if testCase.reason == "missing" {
+				if _, err := os.Stat(filepath.Join(root, testCase.catalog)); !os.IsNotExist(err) {
+					t.Fatalf("qa setup created %q after refusing the catalog root", testCase.catalog)
+				}
+			}
+		})
+	}
+}
+
 func TestQASetupRefusesModelsTheRuntimeDoesNotHave(t *testing.T) {
-	catalog := t.TempDir()
+	catalog := qaSetupCatalogFixture(t)
 	original := qaPiResolver
 	qaPiResolver = fixturePi{must(os.Executable())}
 	t.Cleanup(func() { qaPiResolver = original })
@@ -1022,7 +1117,7 @@ func TestQARunRejectsUnknownAndEmptyRoles(t *testing.T) {
 // for other backends already present in the profile are preserved, and an
 // unadmitted backend token is a usage error.
 func TestQASetupWritesRoutesForTheRequestedBackend(t *testing.T) {
-	catalog := t.TempDir()
+	catalog := qaSetupCatalogFixture(t)
 	original := qaPiResolver
 	qaPiResolver = fixturePi{must(os.Executable())}
 	t.Cleanup(func() { qaPiResolver = original })
diff --git a/internal/cli/qasetup.go b/internal/cli/qasetup.go
index 4a21754..6ead625 100644
--- a/internal/cli/qasetup.go
+++ b/internal/cli/qasetup.go
@@ -51,6 +51,25 @@ func runQASetup(ctx context.Context, args []string, stdout, stderr io.Writer) in
 	if _, admitted := qaroute.RuntimeFor(backend); !admitted {
 		return qaSetupUsage(stderr)
 	}
+	catalogRoot, err := filepath.Abs(catalog)
+	if err != nil {
+		writeError(stderr, "setup_failed")
+		_, _ = fmt.Fprintf(stderr, "%v\n", err)
+		return exitFailure
+	}
+	// The profile is only useful in a catalog `qa run` can load, so setup
+	// validates the existing root before it probes models or writes anything
+	// (#324). A typo is refused instead of materializing a tree no run reads.
+	if err := qapi.ValidateProfileCatalogRoot(catalogRoot); err != nil {
+		writeError(stderr, "setup_failed")
+		rootError, ok := err.(*qapi.ProfileCatalogRootError)
+		if !ok {
+			_, _ = fmt.Fprintf(stderr, "%v\n", err)
+			return exitFailure
+		}
+		_, _ = fmt.Fprintf(stderr, "stage=catalog expected=catalog root containing catalog.json catalog_reason=%s next_check=cortex qa --help\n", rootError.Reason)
+		return exitFailure
+	}
 	// The pi model table is the only surface setup can probe (issue #325):
 	// extension-free pi models. For other backends the operator's pair is
 	// their own runtime's surface, which this process cannot enumerate, so
@@ -71,13 +90,13 @@ func runQASetup(ctx context.Context, args []string, stdout, stderr io.Writer) in
 			return exitFailure
 		}
 	}
-	if err := writeQAProfile(catalog, backend, provider, model, effort); err != nil {
+	if err := writeQAProfile(catalogRoot, backend, provider, model, effort); err != nil {
 		writeError(stderr, "setup_failed")
 		_, _ = fmt.Fprintf(stderr, "%v\n", err)
 		return exitFailure
 	}
 	_, _ = fmt.Fprintf(stdout, "qa route profile written to %s (%d roles -> %s: %s/%s effort=%s)\n",
-		filepath.Join(catalog, "cortex", "qa-profiles.json"), len(qarole.Catalog()), backend, provider, model, effort)
+		filepath.Join(catalogRoot, "cortex", "qa-profiles.json"), len(qarole.Catalog()), backend, provider, model, effort)
 	return exitOK
 }
 
diff --git a/internal/qapi/profile.go b/internal/qapi/profile.go
index 7f84924..ca949e2 100644
--- a/internal/qapi/profile.go
+++ b/internal/qapi/profile.go
@@ -13,6 +13,7 @@ import (
 
 const profileDirectory = "cortex"
 const profileFilename = "qa-profiles.json"
+const profileCatalogFile = "catalog.json"
 
 type profileSource struct {
 	root, directory, file os.FileInfo
@@ -194,3 +195,31 @@ func ProfileSelection(root string) (string, []string, bool) {
 	}
 	return defaultID, ids, true
 }
+
+// ProfileCatalogRootError names why a catalog root cannot host the user-owned
+// route profile. Reason is one fixed token owned by this package.
+type ProfileCatalogRootError struct{ Reason string }
+
+func (err *ProfileCatalogRootError) Error() string {
+	return "catalog root is not usable: " + err.Reason
+}
+
+// ValidateProfileCatalogRoot reports whether root can be the catalog root qa
+// setup writes the route profile into (#324). It holds setup to the agreement
+// qa run depends on: the root must already exist, resolve without symlinks, and
+// carry catalog.json — the file qa run loads. Setup refuses instead of creating
+// the tree, because a typo would otherwise write a profile into a directory no
+// run ever reads.
+func ValidateProfileCatalogRoot(root string) error {
+	if !canonicalProfileRoot(root) {
+		if _, err := os.Lstat(root); os.IsNotExist(err) {
+			return &ProfileCatalogRootError{Reason: "missing"}
+		}
+		return &ProfileCatalogRootError{Reason: "unusable"}
+	}
+	info, err := os.Lstat(filepath.Join(root, profileCatalogFile))
+	if err != nil || info.Mode()&os.ModeSymlink != 0 || !info.Mode().IsRegular() {
+		return &ProfileCatalogRootError{Reason: "catalog_json_missing"}
+	}
+	return nil
+}