zed: delete context_servers key to fix serde parse error; update tests

internal/adapters/zed/zed.go

@@ -52,7 +52,7 @@ func (a *Adapter) Capabilities() adapter.HarnessCapabilities {
 	return adapter.HarnessCapabilities{
 		ManagesProviders:    true,
 		ManagesModels:       true,
-		ManagesMCP:          true,
+		ManagesMCP:          false, // Agent panel uses Extensions; context_servers key causes serde parse errors
 		ManagesSkills:       false,
 		ManagesInstructions: false,
 		HasBuiltInSub:       false,
@@ -67,14 +67,22 @@ func (a *Adapter) Detect() bool {
 
 // Render produces the FileSet that applies the canonical bundle to Zed.
 // settings.json is MERGED to preserve all user-managed Zed configuration.
-// Manages: context_servers (MCP), language_models.openai, agent.default_model.
+// Manages: language_models.openai_compatible, agent.default_model.
+//
+// NOTE: context_servers is NOT written. Zed 1.3+ uses Extension-based MCP
+// servers in the Agent panel; writing context_servers causes a serde parse
+// error (ContextServerSettingsContent untagged enum bug) that aborts loading
+// the entire settings.json. We clear any existing context_servers key to fix
+// pre-existing parse errors from user-configured entries.
 func (a *Adapter) Render(b *canonical.Bundle) (*adapter.FileSet, error) {
 	fs := adapter.NewFileSet()
 	cfgPath := filepath.Join(a.home, ".config", "zed", "settings.json")
 	existing, _ := os.ReadFile(cfgPath)
 
+	// Set context_servers to nil so MergeJSONKeys removes the key entirely,
+	// clearing any entries that trigger the serde ContextServerSettingsContent bug.
 	overlay := map[string]any{
-		"context_servers": common.BuildMCPMapStyled(&b.MCP, common.MCPZedStyle),
+		"context_servers": nil,
 	}
 
 	if b.Profile.Gateway.URL != "" {

internal/adapters/zed/zed_test.go

@@ -58,13 +58,9 @@ func TestZedRenderProducesExpectedTargets(t *testing.T) {
 	gw := oc["harness-sync-gateway"].(map[string]any)
 	assert.Equal(t, "https://llmgw.example.com/v1", gw["api_url"])
 
-	// context_servers — no "enabled" or "source" (Zed serde bug workaround).
-	cs := parsed["context_servers"].(map[string]any)
-	fp := cs["filepuff"].(map[string]any)
-	assert.Equal(t, "/bin/filepuff", fp["command"])
-	assert.Equal(t, []any{"--serve"}, fp["args"])
-	assert.NotContains(t, fp, "enabled")
-	assert.NotContains(t, fp, "source")
+	// context_servers must be absent — Zed serde untagged-enum bug aborts
+	// settings loading when this key is present; we delete it via nil overlay.
+	assert.NotContains(t, parsed, "context_servers")
 }
 
 func TestZedRenderMergesExistingKeys(t *testing.T) {
@@ -96,9 +92,9 @@ func TestZedRenderMergesExistingKeys(t *testing.T) {
 	assert.Equal(t, "One Dark", parsed["theme"])
 	assert.Equal(t, float64(16), parsed["font_size"])
 	assert.Equal(t, true, parsed["vim_mode"])
-	// Managed keys present.
+	// Managed keys present; context_servers absent (serde bug — we delete it).
 	assert.Contains(t, parsed, "agent")
-	assert.Contains(t, parsed, "context_servers")
+	assert.NotContains(t, parsed, "context_servers")
 }
 
 func TestZedRenderNoMCP(t *testing.T) {
@@ -118,10 +114,8 @@ func TestZedRenderNoMCP(t *testing.T) {
 	cfgDest := filepath.Join(home, ".config", "zed", "settings.json")
 	var parsed map[string]any
 	require.NoError(t, json.Unmarshal(seen[cfgDest].Content, &parsed))
-	// context_servers key present but empty map.
-	cs, ok := parsed["context_servers"]
-	assert.True(t, ok)
-	assert.Empty(t, cs)
+	// context_servers must be absent (nil overlay deletes the key).
+	assert.NotContains(t, parsed, "context_servers")
 }
 
 func TestZedRenderEmitsLanguageModelsOpenAICompatible(t *testing.T) {