diff --git a/agent/codex/codex.go b/agent/codex/codex.go
index d7cec6f40..7d7087cdb 100644
--- a/agent/codex/codex.go
+++ b/agent/codex/codex.go
@@ -339,6 +339,7 @@ func (a *Agent) StartSession(ctx context.Context, sessionID string) (core.AgentS
 	codexHome := a.codexHome
 	cliBin := a.cliBin
 	cliExtraArgs := a.cliExtraArgs
+	workDir := a.workDir
 	extraEnv := a.providerEnvLocked()
 	extraEnv = append(extraEnv, a.sessionEnv...)
 	var baseURL string
@@ -361,13 +362,13 @@ func (a *Agent) StartSession(ctx context.Context, sessionID string) (core.AgentS
 	}
 
 	if backend == "app_server" {
-		return newAppServerSession(ctx, appServerURL, a.workDir, model, reasoningEffort, mode, sessionID, baseURL, provName, extraEnv, codexHome)
+		return newAppServerSession(ctx, appServerURL, workDir, model, reasoningEffort, mode, sessionID, baseURL, provName, extraEnv, codexHome)
 	}
 	if codexHome != "" {
 		extraEnv = append(extraEnv, "CODEX_HOME="+codexHome)
 	}
 
-	return newCodexSession(ctx, cliBin, cliExtraArgs, a.workDir, model, reasoningEffort, mode, sessionID, baseURL, extraEnv, provName)
+	return newCodexSession(ctx, cliBin, cliExtraArgs, workDir, model, reasoningEffort, mode, sessionID, baseURL, extraEnv, provName)
 }
 
 func (a *Agent) ListSessions(_ context.Context) ([]core.AgentSessionInfo, error) {
@@ -438,11 +439,15 @@ func (a *Agent) WorkspaceAgentOptions() map[string]any {
 // ── SkillProvider implementation ──────────────────────────────
 
 func (a *Agent) SkillDirs() []string {
-	absDir, err := filepath.Abs(a.workDir)
+	a.mu.RLock()
+	workDir := a.workDir
+	codexHome := a.codexHome
+	a.mu.RUnlock()
+	absDir, err := filepath.Abs(workDir)
 	if err != nil {
-		absDir = a.workDir
+		absDir = workDir
 	}
-	return codexSkillDirs(absDir, a.codexHome)
+	return codexSkillDirs(absDir, codexHome)
 }
 
 // ── ContextCompressor implementation ──────────────────────────
diff --git a/agent/codex/skilldirs_test.go b/agent/codex/skilldirs_test.go
index 28c635f09..418adf608 100644
--- a/agent/codex/skilldirs_test.go
+++ b/agent/codex/skilldirs_test.go
@@ -4,6 +4,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"sync"
 	"testing"
 )
 
@@ -88,3 +89,33 @@ func setTestHome(t *testing.T, home string) {
 		t.Setenv("HOMEPATH", "")
 	}
 }
+
+// TestSkillDirs_RaceFreeAgainstSetWorkDir pins the bug where SkillDirs
+// read a.workDir and a.codexHome without holding a.mu, while
+// SetWorkDir writes a.workDir under the lock. Run with -race to detect
+// the data race; with the production fix the test stays clean.
+func TestSkillDirs_RaceFreeAgainstSetWorkDir(t *testing.T) {
+	tmp := t.TempDir()
+	a := &Agent{workDir: tmp, codexHome: filepath.Join(tmp, "codex")}
+
+	var wg sync.WaitGroup
+	for i := 0; i < 30; i++ {
+		wg.Add(1)
+		go func(i int) {
+			defer wg.Done()
+			if i%2 == 0 {
+				a.SetWorkDir(filepath.Join(tmp, "a"))
+			} else {
+				a.SetWorkDir(filepath.Join(tmp, "b"))
+			}
+		}(i)
+	}
+	for i := 0; i < 30; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			_ = a.SkillDirs()
+		}()
+	}
+	wg.Wait()
+}