fix: Pi proxy mode (#4032)

Author: zreigz

go/deployment-operator/pkg/agentrun-harness/tool/pi/pi.go

@@ -39,7 +39,7 @@ func New(config v1.Config) v1.Tool {
 		}
 	}
 	if config.Run.IsProxyEnabled() {
-		result.provider = openAIProvider
+		result.provider = proxyProviderKey
 		result.model = proxymodel.ProxyModel(console.AgentRuntimeTypePi, result.model)
 	}
 	if err := result.ensure(); err != nil {
@@ -197,9 +197,15 @@ func (in *Pi) writeConfig() error {
 	}
 	provider := in.provider
 	if endpoint != "" {
-		// Pi's custom provider support is OpenAI-compatible. Keep the CLI provider
-		// stable and override its endpoint in the isolated PI config directory.
-		provider = openAIProvider
+		if in.Config.Run.IsProxyEnabled() {
+			// Use a non-"openai" provider key so the Pi CLI does not strip the
+			// "openai/" prefix from the model ID before calling the proxy endpoint.
+			provider = proxyProviderKey
+		} else {
+			// For custom non-proxy endpoints keep the openai provider so Pi uses
+			// its built-in OpenAI-compatible client.
+			provider = openAIProvider
+		}
 		in.provider = provider
 	}
 	models := map[string]any{"providers": map[string]any{}}

go/deployment-operator/pkg/agentrun-harness/tool/pi/pi_test.go

@@ -31,6 +31,27 @@ func TestArgsIncludesJSONModeSessionAndMCPConfig(t *testing.T) {
 	}
 }
 
+func TestArgsWithProxyUsesPluralProvider(t *testing.T) {
+	tool := &Pi{
+		DefaultTool: toolv1.DefaultTool{Config: toolv1.Config{WorkDir: "/work"}},
+		model:       "openai/gpt-5.4",
+		provider:    proxyProviderKey,
+	}
+	want := []string{
+		"--mode", "json",
+		"--approve",
+		"--provider", proxyProviderKey,
+		"--model", "openai/gpt-5.4",
+		"--session-dir", "/work/.pi/agent/sessions",
+		"--extension", piMCPExtensionPath,
+		"--mcp-config", "/work/.pi/agent/mcp.json",
+		"write a task",
+	}
+	if got := tool.args("write a task", ""); !reflect.DeepEqual(got, want) {
+		t.Fatalf("args = %#v, want %#v", got, want)
+	}
+}
+
 func TestMapStreamEventMapsToolLifecycle(t *testing.T) {
 	tool := &Pi{}
 	start, callID := tool.mapStreamEvent(&StreamEvent{

go/deployment-operator/pkg/agentrun-harness/tool/pi/pi_types.go

@@ -9,8 +9,13 @@ import (
 )
 
 const (
-	defaultModel       = "gpt-5.4"
-	openAIProvider     = "openai"
+	defaultModel   = "gpt-5.4"
+	openAIProvider = "openai"
+	// proxyProviderKey is the models.json provider block name used when aiProxy is enabled.
+	// Using a non-"openai" name prevents the Pi CLI from stripping the "openai/" prefix
+	// from model IDs (e.g. "openai/gpt-5.4"), ensuring the full provider/model format
+	// reaches the Plural AI proxy at /ext/ai/v1.
+	proxyProviderKey   = "plural"
 	pluralAPIKeyEnv    = "PLRL_CONSOLE_TOKEN"
 	openAIAPIKeyEnv    = "OPENAI_API_KEY"
 	piMCPExtensionPath = "/opt/pi-mcp-adapter/node_modules/pi-mcp-adapter/index.ts"