defaultAgent/agentStart/.sidecar-agent-start functionality, PR

PRIVACY.md

@@ -54,7 +54,7 @@ In workspace directories, sidecar may create:
 
 - `.sidecar/config.json` — per-project configuration (prompts, theme overrides)
 - `.sidecar/shells.json` — shell display names and metadata
-- `.sidecar-task`, `.sidecar-agent`, `.sidecar-pr`, `.sidecar-base` — workspace state files
+- `.sidecar-task`, `.sidecar-agent`, `.sidecar-agent-start`, `.sidecar-pr`, `.sidecar-base` — workspace state files
 - `.sidecar-start.sh` — temporary agent launcher script
 - `.sidecar-rename-tmp` — temporary file for rename operations
 - `.td-root` — links worktrees to a shared td database root
@@ -81,6 +81,7 @@ Sidecar reads:
 - `HOME` — base path for all config and data directories
 - `EDITOR`, `VISUAL` — to open files in your editor
 - `SIDECAR_PPROF` — profiling server port (development only)
+- `SIDECAR_WORKSPACE_DEFAULT_AGENT_TYPE`, `SIDECAR_DEFAULT_AGENT_TYPE` — override workspace default agent type at startup
 - `XDG_DATA_HOME`, `XDG_CONFIG_HOME`, `XDG_STATE_HOME` — standard directories for locating agent data on Linux
 - `AMP_DATA_HOME` — Amp-specific data directory
 - `APPDATA`, `LOCALAPPDATA` — Windows data directories

internal/config/config.go

@@ -68,6 +68,13 @@ type WorkspacePluginConfig struct {
 	// DirPrefix prefixes workspace directory names with the repo name (e.g., 'myrepo-feature-auth')
 	// This helps associate conversations with the repo after workspace deletion. Default: true.
 	DirPrefix bool `json:"dirPrefix"`
+	// DefaultAgentType sets the default agent family selected when creating a workspace.
+	// Uses workspace.AgentType values (e.g. "claude", "codex", "opencode").
+	DefaultAgentType string `json:"defaultAgentType,omitempty"`
+	// AgentStart maps agent family (AgentType string) to default startup command.
+	// Example: {"claude":"claude", "opencode":"opencode --profile fast"}.
+	// Per-workspace .sidecar-agent-start still takes precedence when present.
+	AgentStart map[string]string `json:"agentStart,omitempty"`
 	// TmuxCaptureMaxBytes caps tmux pane capture size for the preview pane. Default: 2MB.
 	TmuxCaptureMaxBytes int `json:"tmuxCaptureMaxBytes"`
 	// InteractiveExitKey is the keybinding to exit interactive mode. Default: "ctrl+\".
@@ -140,7 +147,7 @@ func Default() *Config {
 			Overrides: make(map[string]string),
 		},
 		UI: UIConfig{
-			ShowClock:  true,
+			ShowClock: true,
 			Theme: ThemeConfig{
 				Name:      "default",
 				Overrides: make(map[string]interface{}),

internal/config/loader.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"bytes"
 	"encoding/json"
 	"log/slog"
 	"os"
@@ -74,16 +75,19 @@ type rawPluginsConfig struct {
 	GitStatus     rawGitStatusConfig     `json:"git-status"`
 	TDMonitor     rawTDMonitorConfig     `json:"td-monitor"`
 	Conversations rawConversationsConfig `json:"conversations"`
-	Workspace     rawWorkspaceConfig      `json:"workspace"`
+	Workspace     rawWorkspaceConfig     `json:"workspace"`
 }
 
 type rawWorkspaceConfig struct {
-	DirPrefix            *bool  `json:"dirPrefix"`
-	TmuxCaptureMaxBytes  *int   `json:"tmuxCaptureMaxBytes"`
-	InteractiveExitKey   string `json:"interactiveExitKey"`
-	InteractiveAttachKey string `json:"interactiveAttachKey"`
-	InteractiveCopyKey   string `json:"interactiveCopyKey"`
-	InteractivePasteKey  string `json:"interactivePasteKey"`
+	DirPrefix            *bool           `json:"dirPrefix"`
+	DefaultAgentType     string          `json:"defaultAgentType"`
+	LegacyDefaultAgent   string          `json:"defaultAgent"` // Backward compatibility
+	AgentStart           json.RawMessage `json:"agentStart"`
+	TmuxCaptureMaxBytes  *int            `json:"tmuxCaptureMaxBytes"`
+	InteractiveExitKey   string          `json:"interactiveExitKey"`
+	InteractiveAttachKey string          `json:"interactiveAttachKey"`
+	InteractiveCopyKey   string          `json:"interactiveCopyKey"`
+	InteractivePasteKey  string          `json:"interactivePasteKey"`
 }
 
 type rawGitStatusConfig struct {
@@ -102,6 +106,11 @@ type rawConversationsConfig struct {
 	ClaudeDataDir string `json:"claudeDataDir"`
 }
 
+const (
+	envWorkspaceDefaultAgentType = "SIDECAR_WORKSPACE_DEFAULT_AGENT_TYPE"
+	envDefaultAgentType          = "SIDECAR_DEFAULT_AGENT_TYPE"
+)
+
 // Load loads configuration from the default location.
 func Load() (*Config, error) {
 	return LoadFrom("")
@@ -115,6 +124,7 @@ func LoadFrom(path string) (*Config, error) {
 	if path == "" {
 		home, err := os.UserHomeDir()
 		if err != nil {
+			applyEnvOverrides(cfg)
 			return cfg, nil // Return defaults on error
 		}
 		path = filepath.Join(home, configDir, configFile)
@@ -123,6 +133,10 @@ func LoadFrom(path string) (*Config, error) {
 	data, err := os.ReadFile(path)
 	if err != nil {
 		if os.IsNotExist(err) {
+			applyEnvOverrides(cfg)
+			if err := cfg.Validate(); err != nil {
+				return nil, err
+			}
 			return cfg, nil // Return defaults if no config file
 		}
 		return nil, err
@@ -135,6 +149,7 @@ func LoadFrom(path string) (*Config, error) {
 
 	// Merge raw config into defaults
 	mergeConfig(cfg, &raw)
+	applyEnvOverrides(cfg)
 
 	// Expand paths
 	cfg.Plugins.Conversations.ClaudeDataDir = ExpandPath(cfg.Plugins.Conversations.ClaudeDataDir)
@@ -209,6 +224,15 @@ func mergeConfig(cfg *Config, raw *rawConfig) {
 	if raw.Plugins.Workspace.TmuxCaptureMaxBytes != nil {
 		cfg.Plugins.Workspace.TmuxCaptureMaxBytes = *raw.Plugins.Workspace.TmuxCaptureMaxBytes
 	}
+	if raw.Plugins.Workspace.DefaultAgentType != "" {
+		cfg.Plugins.Workspace.DefaultAgentType = raw.Plugins.Workspace.DefaultAgentType
+	}
+	if cfg.Plugins.Workspace.DefaultAgentType == "" && raw.Plugins.Workspace.LegacyDefaultAgent != "" {
+		cfg.Plugins.Workspace.DefaultAgentType = raw.Plugins.Workspace.LegacyDefaultAgent
+	}
+	if agentStart, ok := parseAgentStartOverrides(raw.Plugins.Workspace.AgentStart); ok {
+		cfg.Plugins.Workspace.AgentStart = agentStart
+	}
 	if raw.Plugins.Workspace.InteractiveExitKey != "" {
 		cfg.Plugins.Workspace.InteractiveExitKey = raw.Plugins.Workspace.InteractiveExitKey
 	}
@@ -269,6 +293,56 @@ func mergeConfig(cfg *Config, raw *rawConfig) {
 	}
 }
 
+func applyEnvOverrides(cfg *Config) {
+	if cfg == nil {
+		return
+	}
+
+	// SIDECAR_WORKSPACE_DEFAULT_AGENT_TYPE takes precedence over SIDECAR_DEFAULT_AGENT_TYPE,
+	// but only when it is set to a non-blank value. A blank value means "unset" so we fall
+	// through to the lower-priority env var rather than silently dropping it.
+	if v, ok := os.LookupEnv(envWorkspaceDefaultAgentType); ok && strings.TrimSpace(v) != "" {
+		cfg.Plugins.Workspace.DefaultAgentType = strings.TrimSpace(v)
+		return
+	}
+	if v, ok := os.LookupEnv(envDefaultAgentType); ok {
+		cfg.Plugins.Workspace.DefaultAgentType = strings.TrimSpace(v)
+	}
+}
+
+func parseAgentStartOverrides(raw json.RawMessage) (map[string]string, bool) {
+	raw = bytes.TrimSpace(raw)
+	if len(raw) == 0 || bytes.Equal(raw, []byte("null")) {
+		return nil, false
+	}
+
+	var byType map[string]string
+	if err := json.Unmarshal(raw, &byType); err == nil {
+		out := make(map[string]string, len(byType))
+		for k, v := range byType {
+			key := strings.TrimSpace(k)
+			val := strings.TrimSpace(v)
+			if key == "" || val == "" {
+				continue
+			}
+			out[key] = val
+		}
+		return out, true
+	}
+
+	// Backward compatibility: previous schema accepted a single string.
+	var single string
+	if err := json.Unmarshal(raw, &single); err == nil {
+		single = strings.TrimSpace(single)
+		if single == "" {
+			return map[string]string{}, true
+		}
+		return map[string]string{"*": single}, true
+	}
+
+	return nil, false
+}
+
 // ExpandPath expands ~ to home directory.
 func ExpandPath(path string) string {
 	if strings.HasPrefix(path, "~/") {

internal/config/loader_test.go

@@ -184,3 +184,190 @@ func TestLoadFrom_EmptyProjectsList(t *testing.T) {
 		t.Errorf("got %d projects, want 0", len(cfg.Projects.List))
 	}
 }
+
+func TestLoadFrom_WorkspaceAgentSettings(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "config.json")
+
+	content := []byte(`{
+		"plugins": {
+			"workspace": {
+				"defaultAgentType": "opencode",
+				"agentStart": {
+					"opencode": "opencode --profile fast"
+				}
+			}
+		}
+	}`)
+	if err := os.WriteFile(path, content, 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	cfg, err := LoadFrom(path)
+	if err != nil {
+		t.Fatalf("LoadFrom failed: %v", err)
+	}
+
+	if cfg.Plugins.Workspace.DefaultAgentType != "opencode" {
+		t.Errorf("DefaultAgentType = %q, want %q", cfg.Plugins.Workspace.DefaultAgentType, "opencode")
+	}
+	if got := cfg.Plugins.Workspace.AgentStart["opencode"]; got != "opencode --profile fast" {
+		t.Errorf("AgentStart[opencode] = %q, want %q", got, "opencode --profile fast")
+	}
+}
+
+func TestLoadFrom_WorkspaceDefaultAgentTypeEnvOverride(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "config.json")
+	content := []byte(`{
+		"plugins": {
+			"workspace": {
+				"defaultAgentType": "opencode"
+			}
+		}
+	}`)
+	if err := os.WriteFile(path, content, 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	t.Setenv("SIDECAR_WORKSPACE_DEFAULT_AGENT_TYPE", "codex")
+
+	cfg, err := LoadFrom(path)
+	if err != nil {
+		t.Fatalf("LoadFrom failed: %v", err)
+	}
+	if cfg.Plugins.Workspace.DefaultAgentType != "codex" {
+		t.Errorf("DefaultAgentType = %q, want %q", cfg.Plugins.Workspace.DefaultAgentType, "codex")
+	}
+}
+
+func TestLoadFrom_WorkspaceDefaultAgentTypeEnvOverride_NoConfigFile(t *testing.T) {
+	t.Setenv("SIDECAR_WORKSPACE_DEFAULT_AGENT_TYPE", "gemini")
+
+	cfg, err := LoadFrom("/definitely/missing/config.json")
+	if err != nil {
+		t.Fatalf("LoadFrom failed: %v", err)
+	}
+	if cfg.Plugins.Workspace.DefaultAgentType != "gemini" {
+		t.Errorf("DefaultAgentType = %q, want %q", cfg.Plugins.Workspace.DefaultAgentType, "gemini")
+	}
+}
+
+func TestLoadFrom_WorkspaceDefaultAgentTypeEnvOverride_LegacyAlias(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "config.json")
+	content := []byte(`{"plugins":{"workspace":{"defaultAgentType":"opencode"}}}`)
+	if err := os.WriteFile(path, content, 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	t.Setenv("SIDECAR_DEFAULT_AGENT_TYPE", "cursor")
+
+	cfg, err := LoadFrom(path)
+	if err != nil {
+		t.Fatalf("LoadFrom failed: %v", err)
+	}
+	if cfg.Plugins.Workspace.DefaultAgentType != "cursor" {
+		t.Errorf("DefaultAgentType = %q, want %q", cfg.Plugins.Workspace.DefaultAgentType, "cursor")
+	}
+}
+
+func TestLoadFrom_WorkspaceDefaultAgentTypeEnvOverride_PrefersPrimaryVar(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "config.json")
+	content := []byte(`{"plugins":{"workspace":{"defaultAgentType":"opencode"}}}`)
+	if err := os.WriteFile(path, content, 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	t.Setenv("SIDECAR_DEFAULT_AGENT_TYPE", "cursor")
+	t.Setenv("SIDECAR_WORKSPACE_DEFAULT_AGENT_TYPE", "codex")
+
+	cfg, err := LoadFrom(path)
+	if err != nil {
+		t.Fatalf("LoadFrom failed: %v", err)
+	}
+	if cfg.Plugins.Workspace.DefaultAgentType != "codex" {
+		t.Errorf("DefaultAgentType = %q, want %q", cfg.Plugins.Workspace.DefaultAgentType, "codex")
+	}
+}
+
+func TestLoadFrom_WorkspaceAgentStartLegacyStringBackwardCompat(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "config.json")
+	content := []byte(`{
+		"plugins": {
+			"workspace": {
+				"agentStart": "custom-agent --legacy"
+			}
+		}
+	}`)
+	if err := os.WriteFile(path, content, 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	cfg, err := LoadFrom(path)
+	if err != nil {
+		t.Fatalf("LoadFrom failed: %v", err)
+	}
+	if got := cfg.Plugins.Workspace.AgentStart["*"]; got != "custom-agent --legacy" {
+		t.Errorf("AgentStart[*] = %q, want %q", got, "custom-agent --legacy")
+	}
+}
+
+func TestApplyEnvOverrides_WorkspaceVarTakesPrecedence(t *testing.T) {
+	t.Setenv(envWorkspaceDefaultAgentType, "opencode")
+	t.Setenv(envDefaultAgentType, "gemini")
+
+	cfg := Default()
+	applyEnvOverrides(cfg)
+
+	if cfg.Plugins.Workspace.DefaultAgentType != "opencode" {
+		t.Errorf("DefaultAgentType = %q, want %q", cfg.Plugins.Workspace.DefaultAgentType, "opencode")
+	}
+}
+
+func TestApplyEnvOverrides_FallsThruWhenWorkspaceVarBlank(t *testing.T) {
+	// When SIDECAR_WORKSPACE_DEFAULT_AGENT_TYPE is set but blank, we should
+	// NOT short-circuit — SIDECAR_DEFAULT_AGENT_TYPE must still be honoured.
+	t.Setenv(envWorkspaceDefaultAgentType, "   ")
+	t.Setenv(envDefaultAgentType, "gemini")
+
+	cfg := Default()
+	applyEnvOverrides(cfg)
+
+	if cfg.Plugins.Workspace.DefaultAgentType != "gemini" {
+		t.Errorf("DefaultAgentType = %q, want %q (blank workspace var should fall through)", cfg.Plugins.Workspace.DefaultAgentType, "gemini")
+	}
+}
+
+func TestApplyEnvOverrides_OnlyDefaultVar(t *testing.T) {
+	t.Setenv(envDefaultAgentType, "codex")
+
+	cfg := Default()
+	applyEnvOverrides(cfg)
+
+	if cfg.Plugins.Workspace.DefaultAgentType != "codex" {
+		t.Errorf("DefaultAgentType = %q, want %q", cfg.Plugins.Workspace.DefaultAgentType, "codex")
+	}
+}
+
+func TestApplyEnvOverrides_NeitherVarSet(t *testing.T) {
+	cfg := Default()
+	cfg.Plugins.Workspace.DefaultAgentType = "original"
+
+	// Ensure neither env var is set
+	t.Setenv(envWorkspaceDefaultAgentType, "")
+	if err := os.Unsetenv(envWorkspaceDefaultAgentType); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Unsetenv(envDefaultAgentType); err != nil {
+		t.Fatal(err)
+	}
+
+	applyEnvOverrides(cfg)
+
+	if cfg.Plugins.Workspace.DefaultAgentType != "original" {
+		t.Errorf("DefaultAgentType = %q, want %q (should be unchanged)", cfg.Plugins.Workspace.DefaultAgentType, "original")
+	}
+}