feat(config): honor DISPATCH_CONFIG to override config file path

README.md

@@ -429,6 +429,8 @@ Configuration is stored in the platform-specific config directory:
 - **macOS**: `~/Library/Application Support/dispatch/config.json`
 - **Windows**: `%APPDATA%\dispatch\config.json`
 
+Set `DISPATCH_CONFIG` to an absolute file path to use a different config file, for example to keep separate work and personal profiles. `config path`, `config get`/`set`/`edit`, and `doctor` all follow the override. A relative or UNC value is ignored and the default location is used.
+
 ### From the command line
 
 Read and change settings without opening the TUI or editing JSON by hand:
@@ -625,6 +627,7 @@ Unknown flags print an error message with usage help and exit with code 1.
 
 | Variable | Description |
 |---|---|
+| `DISPATCH_CONFIG` | Override the path to the config file. Must be an absolute, non-UNC path; a relative or UNC value is ignored and the default location is used |
 | `DISPATCH_DB` | Override the path to the Copilot CLI session store database |
 | `DISPATCH_LOG` | Path to a log file (enables debug logging) |
 | `DISPATCH_NO_UPDATE_CHECK` | Skip the background release check when set to `1`, `true`, `yes`, or `on` |

internal/config/config.go

@@ -531,15 +531,38 @@ func Default() *Config {
 	}
 }
 
-// configPath returns the full path to the configuration file.
+// configPath returns the full path to the configuration file. When the
+// DISPATCH_CONFIG environment variable holds an absolute, non-UNC path, that
+// path is used instead of the default OS config location. A relative or UNC
+// value is ignored so a bad override falls back to the default.
 func configPath() (string, error) {
+	if override := configPathOverride(); override != "" {
+		return override, nil
+	}
 	dir, err := platform.ConfigDir()
 	if err != nil {
 		return "", err
 	}
 	return filepath.Join(dir, configFileName), nil
 }
 
+// configPathOverride returns a validated config path from the DISPATCH_CONFIG
+// environment variable, or an empty string when the variable is unset or names
+// a relative or UNC path. This mirrors the guard used for the CLI log file so
+// the override cannot point at a network location or a path relative to the
+// current directory.
+func configPathOverride() string {
+	raw := os.Getenv("DISPATCH_CONFIG")
+	if raw == "" {
+		return ""
+	}
+	cleaned := filepath.Clean(raw)
+	if !filepath.IsAbs(cleaned) || strings.HasPrefix(cleaned, `\\`) {
+		return ""
+	}
+	return cleaned
+}
+
 // ConfigPath returns the full path to the configuration file.
 func ConfigPath() (string, error) {
 	return configPath()

internal/config/config_test.go

@@ -722,6 +722,97 @@ func TestConfigPathFormat(t *testing.T) {
 	}
 }
 
+// ---------------------------------------------------------------------------
+// DISPATCH_CONFIG path override
+// ---------------------------------------------------------------------------
+
+func TestConfigPathHonorsDispatchConfigOverride(t *testing.T) {
+	withTempConfigDir(t)
+	custom := filepath.Join(t.TempDir(), "profile.json")
+	t.Setenv("DISPATCH_CONFIG", custom)
+
+	path, err := configPath()
+	if err != nil {
+		t.Fatalf("configPath: %v", err)
+	}
+	if path != custom {
+		t.Errorf("configPath = %q, want override %q", path, custom)
+	}
+	pub, err := ConfigPath()
+	if err != nil {
+		t.Fatalf("ConfigPath: %v", err)
+	}
+	if pub != custom {
+		t.Errorf("ConfigPath = %q, want override %q", pub, custom)
+	}
+}
+
+func TestSaveAndLoadUseDispatchConfigOverride(t *testing.T) {
+	withTempConfigDir(t)
+	custom := filepath.Join(t.TempDir(), "profile.json")
+	t.Setenv("DISPATCH_CONFIG", custom)
+
+	if err := Save(&Config{Agent: "reviewer", Model: "claude-3"}); err != nil {
+		t.Fatalf("Save: %v", err)
+	}
+	if _, err := os.Stat(custom); err != nil {
+		t.Fatalf("override file should exist after Save: %v", err)
+	}
+
+	loaded, err := Load()
+	if err != nil {
+		t.Fatalf("Load: %v", err)
+	}
+	if loaded.Agent != "reviewer" {
+		t.Errorf("Agent = %q, want 'reviewer'", loaded.Agent)
+	}
+	if loaded.Model != "claude-3" {
+		t.Errorf("Model = %q, want 'claude-3'", loaded.Model)
+	}
+}
+
+func TestConfigPathIgnoresUnusableDispatchConfig(t *testing.T) {
+	for _, tc := range []struct {
+		name  string
+		value string
+	}{
+		{name: "relative", value: filepath.Join("nested", "profile.json")},
+		{name: "unc", value: `\\server\share\profile.json`},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			withTempConfigDir(t)
+			t.Setenv("DISPATCH_CONFIG", tc.value)
+
+			path, err := configPath()
+			if err != nil {
+				t.Fatalf("configPath: %v", err)
+			}
+			if filepath.Base(path) != configFileName {
+				t.Errorf("config file name = %q, want %q", filepath.Base(path), configFileName)
+			}
+			if filepath.Base(filepath.Dir(path)) != "dispatch" {
+				t.Errorf("config dir = %q, want default 'dispatch' parent", filepath.Dir(path))
+			}
+		})
+	}
+}
+
+func TestConfigPathUnsetDispatchConfigUsesDefault(t *testing.T) {
+	withTempConfigDir(t)
+	t.Setenv("DISPATCH_CONFIG", "")
+
+	path, err := configPath()
+	if err != nil {
+		t.Fatalf("configPath: %v", err)
+	}
+	if filepath.Base(path) != configFileName {
+		t.Errorf("config file name = %q, want %q", filepath.Base(path), configFileName)
+	}
+	if filepath.Base(filepath.Dir(path)) != "dispatch" {
+		t.Errorf("config dir = %q, want default 'dispatch' parent", filepath.Dir(path))
+	}
+}
+
 func TestDefaultFieldTypes(t *testing.T) {
 	t.Parallel()
 	cfg := Default()