diff --git a/internal/agent/loop.go b/internal/agent/loop.go
index e462d9da..077863fc 100644
--- a/internal/agent/loop.go
+++ b/internal/agent/loop.go
@@ -83,6 +83,9 @@ func (l *Loop) runLoop(ctx context.Context, req RunRequest) (*RunResult, error)
 	if l.sandboxCfg != nil {
 		ctx = tools.WithSandboxConfig(ctx, l.sandboxCfg)
 	}
+	if l.shellDenyGroups != nil {
+		ctx = store.WithShellDenyGroups(ctx, l.shellDenyGroups)
+	}
 
 	// Workspace scope propagation (delegation origin → workspace tools).
 	if req.WorkspaceChannel != "" {
diff --git a/internal/agent/loop_history.go b/internal/agent/loop_history.go
index 82fd963d..6805d1d0 100644
--- a/internal/agent/loop_history.go
+++ b/internal/agent/loop_history.go
@@ -194,6 +194,7 @@ func (l *Loop) buildMessages(ctx context.Context, history []providers.Message, s
 		SandboxEnabled:         l.sandboxEnabled,
 		SandboxContainerDir:    l.sandboxContainerDir,
 		SandboxWorkspaceAccess: l.sandboxWorkspaceAccess,
+		ShellDenyGroups:        l.shellDenyGroups,
 		SelfEvolve:             l.selfEvolve,
 		CredentialCLIContext:   l.buildCredentialCLIContext(ctx),
 		IsBootstrap:            hadBootstrap && l.agentType != "predefined",
diff --git a/internal/agent/loop_types.go b/internal/agent/loop_types.go
index 41224eb8..8a587a26 100644
--- a/internal/agent/loop_types.go
+++ b/internal/agent/loop_types.go
@@ -91,6 +91,9 @@ type Loop struct {
 	sandboxContainerDir    string
 	sandboxWorkspaceAccess string
 
+	// Shell deny group overrides from agent other_config (nil = all defaults)
+	shellDenyGroups map[string]bool
+
 	// Event callback for broadcasting agent events (run.started, chunk, tool.call, etc.)
 	onEvent func(event AgentEvent)
 
@@ -200,6 +203,9 @@ type LoopConfig struct {
 	SandboxContainerDir    string // e.g. "/workspace"
 	SandboxWorkspaceAccess string // "none", "ro", "rw"
 
+	// Shell deny group overrides (nil = all defaults)
+	ShellDenyGroups map[string]bool
+
 	// Agent UUID for context propagation to tools
 	AgentUUID uuid.UUID
 	AgentType string // "open" or "predefined"
@@ -319,6 +325,7 @@ func NewLoop(cfg LoopConfig) *Loop {
 		sandboxEnabled:         cfg.SandboxEnabled,
 		sandboxContainerDir:    cfg.SandboxContainerDir,
 		sandboxWorkspaceAccess: cfg.SandboxWorkspaceAccess,
+		shellDenyGroups:        cfg.ShellDenyGroups,
 		traceCollector:         cfg.TraceCollector,
 		inputGuard:             guard,
 		injectionAction:        action,
diff --git a/internal/agent/resolver.go b/internal/agent/resolver.go
index 651c3eb7..7789e394 100644
--- a/internal/agent/resolver.go
+++ b/internal/agent/resolver.go
@@ -348,6 +348,7 @@ func NewManagedResolver(deps ResolverDeps) ResolverFunc {
 			SkillEvolve:            ag.AgentType == "predefined" && ag.ParseSkillEvolve(),
 			SkillNudgeInterval:     ag.ParseSkillNudgeInterval(),
 			WorkspaceSharing:       ag.ParseWorkspaceSharing(),
+			ShellDenyGroups:        ag.ParseShellDenyGroups(),
 			GroupWriterCache:       deps.GroupWriterCache,
 			TeamStore:              deps.TeamStore,
 			SecureCLIStore:         deps.SecureCLIStore,
diff --git a/internal/store/agent_store.go b/internal/store/agent_store.go
index 605e1858..74ebb38d 100644
--- a/internal/store/agent_store.go
+++ b/internal/store/agent_store.go
@@ -232,6 +232,21 @@ func (a *AgentData) ParseWorkspaceSharing() *WorkspaceSharingConfig {
 	return cfg.WS
 }
 
+// ParseShellDenyGroups extracts shell_deny_groups from other_config JSONB.
+// Returns nil if not configured (all defaults apply).
+func (a *AgentData) ParseShellDenyGroups() map[string]bool {
+	if len(a.OtherConfig) == 0 {
+		return nil
+	}
+	var cfg struct {
+		ShellDenyGroups map[string]bool `json:"shell_deny_groups"`
+	}
+	if json.Unmarshal(a.OtherConfig, &cfg) != nil || len(cfg.ShellDenyGroups) == 0 {
+		return nil
+	}
+	return cfg.ShellDenyGroups
+}
+
 // AgentShareData represents an agent share grant.
 type AgentShareData struct {
 	BaseModel
diff --git a/internal/tools/message_test.go b/internal/tools/message_test.go
index 27b340a6..9f8c19a0 100644
--- a/internal/tools/message_test.go
+++ b/internal/tools/message_test.go
@@ -21,8 +21,13 @@ func TestResolveMediaPath(t *testing.T) {
 		t.Fatal(err)
 	}
 
+	// Normalize paths to canonical form (resolves macOS /var/folders → /private/var/folders symlink).
+	// The resolvePath function uses filepath.EvalSymlinks, so test expectations must too.
+	testFileCanonical, _ := filepath.EvalSymlinks(testFile)
+	workspaceCanonical, _ := filepath.EvalSymlinks(workspace)
+
 	t.Run("restricted", func(t *testing.T) {
-		tool := NewMessageTool(workspace, true)
+		tool := NewMessageTool(workspaceCanonical, true)
 		ctx := context.Background()
 
 		tests := []struct {
@@ -36,8 +41,8 @@ func TestResolveMediaPath(t *testing.T) {
 			{"valid nested temp", "MEDIA:" + filepath.Join(tmpDir, "sub", "file.txt"), filepath.Join(tmpDir, "sub", "file.txt"), true},
 
 			// Workspace files allowed
-			{"workspace absolute", "MEDIA:" + testFile, testFile, true},
-			{"workspace relative", "MEDIA:docs/report.pdf", testFile, true},
+			{"workspace absolute", "MEDIA:" + testFileCanonical, testFileCanonical, true},
+			{"workspace relative", "MEDIA:docs/report.pdf", testFileCanonical, true},
 
 			// Not a MEDIA: message
 			{"no prefix", filepath.Join(tmpDir, "test.png"), "", false},
@@ -48,7 +53,7 @@ func TestResolveMediaPath(t *testing.T) {
 
 			// Outside workspace + outside /tmp/ → blocked
 			{"outside workspace", "MEDIA:/etc/passwd", "", false},
-			{"traversal attack", "MEDIA:" + filepath.Join(workspace, "..", "etc", "passwd"), "", false},
+			{"traversal attack", "MEDIA:" + filepath.Join(workspaceCanonical, "..", "etc", "passwd"), "", false},
 		}
 
 		for _, tt := range tests {
@@ -91,14 +96,14 @@ func TestResolveMediaPath(t *testing.T) {
 	t.Run("context workspace override", func(t *testing.T) {
 		// Tool has no workspace, but context provides one.
 		tool := NewMessageTool("", true)
-		ctx := WithToolWorkspace(context.Background(), workspace)
+		ctx := WithToolWorkspace(context.Background(), workspaceCanonical)
 
 		got, ok := tool.resolveMediaPath(ctx, "MEDIA:docs/report.pdf")
 		if !ok {
 			t.Fatal("expected ok=true for workspace-relative path with context workspace")
 		}
-		if got != testFile {
-			t.Errorf("got %q, want %q", got, testFile)
+		if got != testFileCanonical {
+			t.Errorf("got %q, want %q", got, testFileCanonical)
 		}
 	})
 }