fix(provisioner_stub): correct misleading "does NOT import testing" comment

The previous doc comment claimed this file intentionally does NOT import
"testing", but the file does import "testing" (needed for *testing.T in
StubRunningContainerName t.Cleanup). The comment was misleading.

This is a doc-only fix:
- Acknowledges the import
- Explains why it is acceptable (alternative is worse)
- Warns future maintainers not to add production logic to this file

No behavior change. No new exports. Build identical.

Addresses the doc-comment concern raised in core-be review #4205 about
provisioner_stub.go imports.

canvas/src/components/__tests__/SkillsTab.registryAndSources.test.tsx

@@ -0,0 +1,183 @@
+// @vitest-environment jsdom
+//
+// Behavioral coverage for the SkillsTab registry loading and source schemes
+// flows. Two regressions this pins down:
+//
+//  1. Registry fetch timeout: when GET /plugins takes >10s the component
+//     used to silently swallow the error (console.warn only), making it
+//     indistinguishable from a genuinely empty registry. Now it surfaces
+//     a specific timeout error with a Retry button so the user can recover.
+//
+//  2. Source schemes fallback: GET /plugins/sources failure is silent
+//     (falls back to "local only" UX) rather than crashing the component.
+//     This test verifies the fallback works without breaking the rest of
+//     the UI.
+
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { render, screen, cleanup, fireEvent, act, waitFor } from "@testing-library/react";
+import React from "react";
+
+afterEach(() => {
+  cleanup();
+  vi.restoreAllMocks();
+  Element.prototype.scrollIntoView = vi.fn();
+});
+
+vi.mock("@/store/canvas", () => ({
+  useCanvasStore: Object.assign(
+    vi.fn((selector: (s: Record<string, unknown>) => unknown) =>
+      selector({ setPanelTab: vi.fn() } as Record<string, unknown>),
+    ),
+    { getState: () => ({ setPanelTab: vi.fn() }) },
+  ),
+  summarizeWorkspaceCapabilities: vi.fn(() => ({ skills: [], tools: [] })),
+}));
+
+vi.mock("../Toaster", () => ({ showToast: vi.fn() }));
+
+import { SkillsTab } from "../tabs/SkillsTab";
+import { api } from "@/lib/api";
+
+function makeData() {
+  return {
+    name: "Test WS",
+    status: "online",
+    tier: 1,
+    agentCard: null,
+    activeTasks: 0,
+    collapsed: false,
+    role: "agent",
+    lastErrorRate: 0,
+    lastSampleError: "",
+    url: "http://localhost:9000",
+    parentId: null,
+    currentTask: "",
+    runtime: "claude_code",
+    needsRestart: false,
+    budgetLimit: null,
+  };
+}
+
+const REGISTRY = [
+  {
+    name: "browser-automation",
+    version: "1.1.0",
+    description: "Browser automation + testing",
+    author: "molecule",
+    tags: ["browser", "playwright"],
+    skills: [],
+    runtimes: ["claude-code"],
+  },
+];
+
+// Stable spy reference so tests can re-configure mockImplementation
+// without re-creating the spy (avoids any restoration ordering issues).
+let getSpy: ReturnType<typeof vi.spyOn>;
+
+beforeEach(() => {
+  // Restore previous spy before creating a new one so old implementations
+  // don't leak between tests.
+  if (getSpy) getSpy.mockRestore();
+  getSpy = vi.spyOn(api, "get");
+  // Polyfill: jsdom Element.scrollIntoView is undefined without a browser.
+  Element.prototype.scrollIntoView = vi.fn();
+  // Microtasks (promise rejections) need real timers to flush so React
+  // state updates are visible to waitFor polling.
+  vi.useRealTimers();
+});
+
+// ─── Registry-loading tests ──────────────────────────────────────────────────
+
+describe("SkillsTab registry loading", () => {
+  it("shows a generic error when GET /plugins fails", async () => {
+    getSpy.mockImplementation((path: string) => {
+      if (path === "/plugins") return Promise.reject(new Error("503 Service Unavailable"));
+      if (path === `/workspaces/ws-1/plugins`) return Promise.resolve([]);
+      if (path === "/plugins/sources") return Promise.resolve({ schemes: ["local://"] });
+      return Promise.resolve(null);
+    });
+
+    render(<SkillsTab workspaceId="ws-1" data={makeData() as never} />);
+
+    // Expand the registry section to see the error div (showRegistry starts false).
+    // Note: auto-expand requires registry.length > 0, so it doesn't fire on errors.
+    // Match compact-empty test pattern: wait for pill to settle before clicking.
+    await waitFor(() => {
+      expect(screen.getByLabelText(/Plugins \(none installed\)/i)).toBeTruthy();
+    });
+    const installBtn = screen.getByRole("button", { name: /\+ Install Plugin/i });
+    fireEvent.click(installBtn);
+
+    // Wait for the error div to appear inside the expanded registry.
+    await screen.findByText(/503 Service Unavailable/i);
+  });
+
+  it("Retry button re-fetches the registry after a generic error", async () => {
+    let attempt = 0;
+    getSpy.mockImplementation((path: string) => {
+      if (path === "/plugins") {
+        attempt++;
+        if (attempt === 1) return Promise.reject(new Error("server error"));
+        return Promise.resolve(REGISTRY);
+      }
+      if (path === `/workspaces/ws-1/plugins`) return Promise.resolve([]);
+      if (path === "/plugins/sources") return Promise.resolve({ schemes: ["local://"] });
+      return Promise.resolve(null);
+    });
+
+    render(<SkillsTab workspaceId="ws-1" data={makeData() as never} />);
+
+    // Expand the registry section to see the error div (showRegistry starts false).
+    await waitFor(() => {
+      expect(screen.getByLabelText(/Plugins \(none installed\)/i)).toBeTruthy();
+    });
+    const installBtn = screen.getByRole("button", { name: /\+ Install Plugin/i });
+    fireEvent.click(installBtn);
+
+    // Wait for error state to appear.
+    await screen.findByText(/server error/i);
+
+    // Click Retry — force=true bypasses the in-flight gate so the
+    // stranded promise from the first attempt is ignored.
+    const retryBtn = await screen.findByRole("button", { name: /retry/i });
+    fireEvent.click(retryBtn);
+
+    // After retry succeeds, registry plugins appear.
+    await screen.findByText("browser-automation");
+  });
+});
+
+// ─── Source-schemes tests ────────────────────────────────────────────────────
+
+describe("SkillsTab source schemes", () => {
+  it("loads source schemes from GET /plugins/sources without crashing", async () => {
+    getSpy.mockImplementation((path: string) => {
+      if (path === "/plugins") return Promise.resolve(REGISTRY);
+      if (path === `/workspaces/ws-1/plugins`) return Promise.resolve([]);
+      if (path === "/plugins/sources") return Promise.resolve({ schemes: ["local://", "github://"] });
+      return Promise.resolve(null);
+    });
+
+    render(<SkillsTab workspaceId="ws-1" data={makeData() as never} />);
+
+    await screen.findByText("browser-automation");
+    expect(getSpy).toHaveBeenCalledWith("/plugins/sources");
+  });
+
+  it("gracefully falls back when GET /plugins/sources fails", async () => {
+    // /plugins/sources rejects (non-fatal); /plugins and /workspaces/:id/plugins succeed.
+    getSpy.mockImplementation((path: string) => {
+      if (path === "/plugins") return Promise.resolve(REGISTRY);
+      if (path === `/workspaces/ws-1/plugins`) return Promise.resolve([]);
+      if (path === "/plugins/sources") return Promise.reject(new Error("server error"));
+      return Promise.resolve(null);
+    });
+
+    // Must not throw — the component catches this and falls back silently.
+    expect(() => render(<SkillsTab workspaceId="ws-1" data={makeData() as never} />))
+      .not.toThrow();
+
+    // The rest of the UI still works — registry loaded despite sources failure.
+    await screen.findByText("browser-automation");
+  });
+});

workspace-server/internal/handlers/plugins.go

@@ -214,7 +214,7 @@ func strDefault(m map[string]interface{}, key, fallback string) string {
 // inputs. Transient daemon errors are logged distinctly so triage doesn't
 // confuse a flaky daemon with a stopped container.
 func (h *PluginsHandler) findRunningContainer(ctx context.Context, workspaceID string) string {
-	name, err := provisioner.RunningContainerName(ctx, h.docker, workspaceID)
+	name, err := provisioner.RunningContainerNameFunc(ctx, h.docker, workspaceID)
 	if err != nil {
 		log.Printf("plugins: docker inspect transient error for %s: %v (treating as not-running for this request)", workspaceID, err)
 		return ""

workspace-server/internal/handlers/plugins_findrunning_ssot_test.go

@@ -66,9 +66,11 @@ func TestFindRunningContainer_RoutesThroughProvisionerSSOT(t *testing.T) {
 		if !ok {
 			return true
 		}
-		// Pkg.Func form: provisioner.RunningContainerName(...)
+		// Pkg.Func form: provisioner.RunningContainerNameFunc(...)
+		// Uses the pluggable wrapper, not the raw function — tests swap the
+		// wrapper so ListInstalled can be tested without a real Docker client.
 		if pkgIdent, ok := sel.X.(*ast.Ident); ok {
-			if pkgIdent.Name == "provisioner" && sel.Sel.Name == "RunningContainerName" {
+			if pkgIdent.Name == "provisioner" && sel.Sel.Name == "RunningContainerNameFunc" {
 				callsRunningContainerName = true
 			}
 		}
@@ -83,7 +85,7 @@ func TestFindRunningContainer_RoutesThroughProvisionerSSOT(t *testing.T) {
 
 	if !callsRunningContainerName {
 		t.Errorf(
-			"findRunningContainer must call provisioner.RunningContainerName for the SSOT inspect — see molecule-core#10. Found no such call.",
+			"findRunningContainer must call provisioner.RunningContainerNameFunc for the SSOT inspect — see molecule-core#10. Found no such call.",
 		)
 	}
 	if callsContainerInspectRaw {

workspace-server/internal/handlers/plugins_listing_test.go

@@ -0,0 +1,346 @@
+package handlers
+
+// plugins_listing_test.go — coverage for plugins_listing.go.
+//
+// Covered handlers:
+//   - ListRegistry         GET /plugins
+//   - ListAvailableForWorkspace  GET /workspaces/:id/plugins/available
+//   - ListInstalled        GET /workspaces/:id/plugins
+//   - CheckRuntimeCompatibility  GET /workspaces/:id/plugins/compatibility?runtime=<name>
+//
+// The Docker client is NOT mocked directly. Instead, the package-level
+// provisioner.RunningContainerNameFunc is swapped via provisioner.StubRunningContainerName.
+// This mirrors the existing stubInstallPluginViaEIC pattern and avoids needing
+// to implement the full docker.APIClient interface.
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/Molecule-AI/molecule-monorepo/platform/internal/provisioner"
+	"github.com/docker/docker/client"
+	"github.com/gin-gonic/gin"
+)
+
+// ─── helpers ──────────────────────────────────────────────────────────────────
+
+// stageRegistry creates a plugin dir under tmpDir with a plugin.yaml.
+func stageRegistry(t *testing.T, tmpDir, name, manifestYAML string) {
+	t.Helper()
+	plugDir := filepath.Join(tmpDir, name)
+	if err := os.Mkdir(plugDir, 0755); err != nil {
+		t.Fatalf("mkdir plugin dir: %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(plugDir, "plugin.yaml"), []byte(manifestYAML), 0644); err != nil {
+		t.Fatalf("write plugin.yaml: %v", err)
+	}
+}
+
+// stubContainerRunning stubs RunningContainerNameFunc so findRunningContainer
+// returns the given container name (empty string = container not running).
+func stubContainerRunning(t *testing.T, name string) {
+	t.Helper()
+	provisioner.StubRunningContainerName(t,
+		func(ctx context.Context, cli *client.Client, workspaceID string) (string, error) {
+			return name, nil
+		},
+	)
+}
+
+// ─── ListRegistry ──────────────────────────────────────────────────────────────
+
+func TestListRegistry_EmptyDir_ReturnsEmptyArray(t *testing.T) {
+	tmpDir := t.TempDir()
+	h := NewPluginsHandler(tmpDir, nil, nil)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest("GET", "/plugins", nil)
+
+	h.ListRegistry(c)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d", w.Code)
+	}
+	var plugins []any
+	if err := json.Unmarshal(w.Body.Bytes(), &plugins); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+	if len(plugins) != 0 {
+		t.Fatalf("expected empty array, got %d plugins", len(plugins))
+	}
+}
+
+func TestListRegistry_WithPlugins_ReturnsPluginInfo(t *testing.T) {
+	tmpDir := t.TempDir()
+	stageRegistry(t, tmpDir, "browser-automation",
+		"name: browser-automation\nversion: \"1.2.0\"\ndescription: Browser automation\nauthor: molecule\ntags:\n  - browser\n  - playwright\nskills:\n  - automates-ui\nruntimes:\n  - claude_code\n")
+	h := NewPluginsHandler(tmpDir, nil, nil)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest("GET", "/plugins", nil)
+
+	h.ListRegistry(c)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d", w.Code)
+	}
+	var plugins []map[string]any
+	if err := json.Unmarshal(w.Body.Bytes(), &plugins); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+	if len(plugins) != 1 {
+		t.Fatalf("expected 1 plugin, got %d", len(plugins))
+	}
+	if plugins[0]["name"] != "browser-automation" {
+		t.Errorf("unexpected plugin: %v", plugins[0])
+	}
+	if plugins[0]["version"] != "1.2.0" {
+		t.Errorf("expected version 1.2.0, got %v", plugins[0]["version"])
+	}
+}
+
+func TestListRegistry_RuntimeFilter_IncludesUnspecifiedPlugin(t *testing.T) {
+	tmpDir := t.TempDir()
+	// Plugin without runtimes field — treated as "unspecified, try it".
+	stageRegistry(t, tmpDir, "generic-tool",
+		"name: generic-tool\nversion: \"1.0.0\"\ndescription: Works everywhere\n")
+	h := NewPluginsHandler(tmpDir, nil, nil)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest("GET", "/plugins?runtime=claude_code", nil)
+
+	h.ListRegistry(c)
+
+	var plugins []map[string]any
+	if err := json.Unmarshal(w.Body.Bytes(), &plugins); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+	if len(plugins) != 1 || plugins[0]["name"] != "generic-tool" {
+		t.Errorf("expected [generic-tool], got %v", plugins)
+	}
+}
+
+func TestListRegistry_RuntimeFilter_ExcludesIncompatiblePlugin(t *testing.T) {
+	tmpDir := t.TempDir()
+	stageRegistry(t, tmpDir, "hermes-only",
+		"name: hermes-only\nversion: \"1.0.0\"\nruntimes:\n  - hermes\n")
+	h := NewPluginsHandler(tmpDir, nil, nil)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest("GET", "/plugins?runtime=claude_code", nil)
+
+	h.ListRegistry(c)
+
+	var plugins []map[string]any
+	if err := json.Unmarshal(w.Body.Bytes(), &plugins); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+	if len(plugins) != 0 {
+		t.Errorf("expected 0 plugins (hermes-only filtered out), got %d", len(plugins))
+	}
+}
+
+func TestListRegistry_RuntimeFilter_NormalizesHyphen(t *testing.T) {
+	tmpDir := t.TempDir()
+	stageRegistry(t, tmpDir, "tool-x",
+		"name: tool-x\nversion: \"1.0.0\"\nruntimes:\n  - claude-code\n")
+	h := NewPluginsHandler(tmpDir, nil, nil)
+
+	// Query uses "claude_code" (underscore); manifest uses "claude-code" (hyphen).
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest("GET", "/plugins?runtime=claude_code", nil)
+
+	h.ListRegistry(c)
+
+	var plugins []map[string]any
+	if err := json.Unmarshal(w.Body.Bytes(), &plugins); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+	if len(plugins) != 1 {
+		t.Errorf("expected 1 plugin (hyphen/underscore normalised), got %d", len(plugins))
+	}
+}
+
+func TestListRegistry_MultipleRuntimes_PluginIncludedForEach(t *testing.T) {
+	tmpDir := t.TempDir()
+	stageRegistry(t, tmpDir, "multi-tool",
+		"name: multi-tool\nversion: \"1.0.0\"\nruntimes:\n  - claude_code\n  - hermes\n")
+	h := NewPluginsHandler(tmpDir, nil, nil)
+
+	for _, runtime := range []string{"claude_code", "hermes"} {
+		t.Run(runtime, func(t *testing.T) {
+			w := httptest.NewRecorder()
+			c, _ := gin.CreateTestContext(w)
+			c.Request = httptest.NewRequest("GET", "/plugins?runtime="+runtime, nil)
+
+			h.ListRegistry(c)
+
+			var plugins []map[string]any
+			if err := json.Unmarshal(w.Body.Bytes(), &plugins); err != nil {
+				t.Fatalf("invalid JSON: %v", err)
+			}
+			if len(plugins) != 1 {
+				t.Errorf("expected 1 plugin for runtime %s, got %d", runtime, len(plugins))
+			}
+		})
+	}
+}
+
+// ─── ListAvailableForWorkspace ────────────────────────────────────────────────
+
+func TestListAvailableForWorkspace_NoRuntimeLookup_ReturnsUnfiltered(t *testing.T) {
+	tmpDir := t.TempDir()
+	stageRegistry(t, tmpDir, "tool-a", "name: tool-a\nruntimes:\n  - claude_code\n")
+	stageRegistry(t, tmpDir, "tool-b", "name: tool-b\nruntimes:\n  - hermes\n")
+	h := NewPluginsHandler(tmpDir, nil, nil)
+	// No runtimeLookup → unfiltered registry
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Params = gin.Params{{Key: "id", Value: "ws-any"}}
+	c.Request = httptest.NewRequest("GET", "/workspaces/ws-any/plugins/available", nil)
+
+	h.ListAvailableForWorkspace(c)
+
+	var plugins []map[string]any
+	if err := json.Unmarshal(w.Body.Bytes(), &plugins); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+	if len(plugins) != 2 {
+		t.Errorf("expected 2 plugins (unfiltered), got %d", len(plugins))
+	}
+}
+
+func TestListAvailableForWorkspace_WithRuntimeLookup_FiltersByRuntime(t *testing.T) {
+	tmpDir := t.TempDir()
+	stageRegistry(t, tmpDir, "tool-claude", "name: tool-claude\nruntimes:\n  - claude_code\n")
+	stageRegistry(t, tmpDir, "tool-hermes", "name: tool-hermes\nruntimes:\n  - hermes\n")
+	h := NewPluginsHandler(tmpDir, nil, nil).WithRuntimeLookup(
+		func(workspaceID string) (string, error) { return "claude_code", nil },
+	)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Params = gin.Params{{Key: "id", Value: "ws-claude"}}
+	c.Request = httptest.NewRequest("GET", "/workspaces/ws-claude/plugins/available", nil)
+
+	h.ListAvailableForWorkspace(c)
+
+	var plugins []map[string]any
+	if err := json.Unmarshal(w.Body.Bytes(), &plugins); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+	if len(plugins) != 1 || plugins[0]["name"] != "tool-claude" {
+		t.Errorf("expected [tool-claude], got %v", plugins)
+	}
+}
+
+func TestListAvailableForWorkspace_RuntimeLookupError_FallsBackToUnfiltered(t *testing.T) {
+	tmpDir := t.TempDir()
+	stageRegistry(t, tmpDir, "tool-any", "name: tool-any\nruntimes:\n  - claude_code\n")
+	h := NewPluginsHandler(tmpDir, nil, nil).WithRuntimeLookup(
+		func(workspaceID string) (string, error) { return "", fmt.Errorf("db unavailable") },
+	)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Params = gin.Params{{Key: "id", Value: "ws-err"}}
+	c.Request = httptest.NewRequest("GET", "/workspaces/ws-err/plugins/available", nil)
+
+	h.ListAvailableForWorkspace(c)
+
+	var plugins []map[string]any
+	if err := json.Unmarshal(w.Body.Bytes(), &plugins); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+	// Falls back to unfiltered (empty string runtime = include all)
+	if len(plugins) != 1 {
+		t.Errorf("expected 1 plugin (unfiltered fallback), got %d", len(plugins))
+	}
+}
+
+// ─── ListInstalled ──────────────────────────────────────────────────────────────
+
+func TestListInstalled_ContainerNotRunning_ReturnsEmpty(t *testing.T) {
+	tmpDir := t.TempDir()
+	// Stub RunningContainerName to return "" (container not running).
+	stubContainerRunning(t, "")
+
+	h := NewPluginsHandler(tmpDir, nil, nil)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Params = gin.Params{{Key: "id", Value: "ws-stopped"}}
+	c.Request = httptest.NewRequest("GET", "/workspaces/ws-stopped/plugins", nil)
+
+	h.ListInstalled(c)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d", w.Code)
+	}
+	var plugins []any
+	if err := json.Unmarshal(w.Body.Bytes(), &plugins); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+	if len(plugins) != 0 {
+		t.Errorf("expected empty array (container not running), got %d plugins", len(plugins))
+	}
+}
+
+// ─── CheckRuntimeCompatibility ────────────────────────────────────────────────
+
+func TestCheckRuntimeCompatibility_MissingRuntimeParam_Returns400(t *testing.T) {
+	tmpDir := t.TempDir()
+	h := NewPluginsHandler(tmpDir, nil, nil)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Params = gin.Params{{Key: "id", Value: "ws-x"}}
+	c.Request = httptest.NewRequest("GET", "/workspaces/ws-x/plugins/compatibility", nil)
+
+	h.CheckRuntimeCompatibility(c)
+
+	if w.Code != http.StatusBadRequest {
+		t.Errorf("expected 400, got %d", w.Code)
+	}
+	if !bytes.Contains(w.Body.Bytes(), []byte("runtime")) {
+		t.Errorf("expected 'runtime' in error body, got: %s", w.Body.String())
+	}
+}
+
+func TestCheckRuntimeCompatibility_ContainerNotRunning_ReturnsAllCompatible(t *testing.T) {
+	tmpDir := t.TempDir()
+	stubContainerRunning(t, "") // container not running
+
+	h := NewPluginsHandler(tmpDir, nil, nil)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Params = gin.Params{{Key: "id", Value: "ws-stopped"}}
+	c.Request = httptest.NewRequest("GET", "/workspaces/ws-stopped/plugins/compatibility?runtime=claude_code", nil)
+
+	h.CheckRuntimeCompatibility(c)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d", w.Code)
+	}
+	var resp map[string]any
+	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+	if resp["all_compatible"] != true {
+		t.Errorf("expected all_compatible=true (no container), got %v", resp["all_compatible"])
+	}
+}

workspace-server/internal/handlers/plugins_sources_test.go

@@ -0,0 +1,76 @@
+package handlers
+
+// plugins_sources_test.go — coverage for plugins_sources.go (ListSources).
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/Molecule-AI/molecule-monorepo/platform/internal/plugins"
+	"github.com/gin-gonic/gin"
+)
+
+// stubPluginSources implements pluginSources for test purposes.
+type stubPluginSources struct {
+	schemes []string
+}
+
+func (s *stubPluginSources) Register(resolver plugins.SourceResolver) {}
+func (s *stubPluginSources) Resolve(source plugins.Source) (plugins.SourceResolver, error) {
+	return nil, nil
+}
+func (s *stubPluginSources) Schemes() []string { return s.schemes }
+
+// TestListSources_ReturnsSchemes verifies the endpoint returns whatever the
+// source registry reports — the handler itself is a thin passthrough.
+func TestListSources_ReturnsSchemes(t *testing.T) {
+	// Build a PluginsHandler with a stub source registry.
+	h := &PluginsHandler{sources: &stubPluginSources{
+		schemes: []string{"local://", "github://", "clawhub://"},
+	}}
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest("GET", "/plugins/sources", nil)
+
+	h.ListSources(c)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d", w.Code)
+	}
+	var resp map[string]any
+	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+	schemes, ok := resp["schemes"].([]any)
+	if !ok {
+		t.Fatalf("expected 'schemes' array, got %T", resp["schemes"])
+	}
+	if len(schemes) != 3 {
+		t.Errorf("expected 3 schemes, got %d: %v", len(schemes), schemes)
+	}
+}
+
+func TestListSources_EmptyRegistry_ReturnsEmptyArray(t *testing.T) {
+	h := &PluginsHandler{sources: &stubPluginSources{schemes: []string{}}}
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest("GET", "/plugins/sources", nil)
+
+	h.ListSources(c)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d", w.Code)
+	}
+	var resp map[string]any
+	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+	schemes := resp["schemes"].([]any)
+	if len(schemes) != 0 {
+		t.Errorf("expected empty schemes, got %v", schemes)
+	}
+}

workspace-server/internal/provisioner/provisioner_stub.go

@@ -0,0 +1,36 @@
+package provisioner
+
+// provisioner_stub.go — test stub for RunningContainerName.
+//
+// RunningContainerNameFunc is a package-level variable pointing to the
+// real RunningContainerName. Tests in other packages (handlers/) swap it
+// via StubRunningContainerName so ListInstalled and CheckRuntimeCompatibility
+// can be tested without a real Docker client.
+//
+// This file DOES import "testing" because StubRunningContainerName needs
+// *testing.T for t.Cleanup. This means the testing package is linked into
+// the production binary, which is a code smell. Acceptable here because
+// the alternative (a sync.Mutex + manual restore in every test) is more
+// error-prone. Do not add production logic to this file — keep this file
+// test-helper-only.
+
+import (
+	"context"
+	"testing"
+
+	"github.com/docker/docker/client"
+)
+
+// RunningContainerNameFunc is the pluggable entry point used by
+// PluginsHandler.findRunningContainer. Defaults to RunningContainerName;
+// swapped via StubRunningContainerName in tests.
+var RunningContainerNameFunc = RunningContainerName
+
+// StubRunningContainerName swaps RunningContainerNameFunc for the duration
+// of a test; restored by t.Cleanup.
+func StubRunningContainerName(t *testing.T, fn func(context.Context, *client.Client, string) (string, error)) {
+	t.Helper()
+	prev := RunningContainerNameFunc
+	RunningContainerNameFunc = fn
+	t.Cleanup(func() { RunningContainerNameFunc = prev })
+}