fission-ai__openspec/openspec/specs/global-config/spec.md

global-config Specification

Purpose

This spec defines how OpenSpec resolves, reads, and writes user-level global configuration. It governs the src/core/global-config.ts module, which provides the foundation for storing user preferences, feature flags, and settings that persist across projects. The spec ensures cross-platform compatibility by following XDG Base Directory Specification with platform-specific fallbacks, and guarantees forward/backward compatibility through schema evolution rules.

Requirements

Requirement: Global Config Directory Path

The system SHALL resolve the global configuration directory path following XDG Base Directory Specification with platform-specific fallbacks.

Scenario: Unix/macOS with XDG_CONFIG_HOME set

• WHEN $XDG_CONFIG_HOME environment variable is set to /custom/config
• THEN getGlobalConfigDir() returns /custom/config/openspec

Scenario: Unix/macOS without XDG_CONFIG_HOME

• WHEN $XDG_CONFIG_HOME environment variable is not set
• AND the platform is Unix or macOS
• THEN getGlobalConfigDir() returns ~/.config/openspec (expanded to absolute path)

Scenario: Windows platform

• WHEN the platform is Windows
• AND %APPDATA% is set to C:\Users\User\AppData\Roaming
• THEN getGlobalConfigDir() returns C:\Users\User\AppData\Roaming\openspec

Requirement: Global Config Loading

The system SHALL load global configuration from the config directory with sensible defaults when the config file does not exist or cannot be parsed.

Scenario: Config file exists and is valid

• WHEN config.json exists in the global config directory
• AND the file contains valid JSON matching the config schema
• THEN getGlobalConfig() returns the parsed configuration

Scenario: Config file does not exist

• WHEN config.json does not exist in the global config directory
• THEN getGlobalConfig() returns the default configuration
• AND no directory or file is created

Scenario: Config file is invalid JSON

• WHEN config.json exists but contains invalid JSON
• THEN getGlobalConfig() returns the default configuration
• AND a warning is logged to stderr

Requirement: Global Config Saving

The system SHALL save global configuration to the config directory, creating the directory if it does not exist.

Scenario: Save config to new directory

• WHEN saveGlobalConfig(config) is called
• AND the global config directory does not exist
• THEN the directory is created
• AND config.json is written with the provided configuration

Scenario: Save config to existing directory

• WHEN saveGlobalConfig(config) is called
• AND the global config directory already exists
• THEN config.json is written (overwriting if exists)

Requirement: Default Configuration

The system SHALL provide a default configuration that is used when no config file exists.

Scenario: Default config structure

• WHEN no config file exists
• THEN the default configuration includes an empty featureFlags object

Requirement: Config Schema Evolution

The system SHALL merge loaded configuration with default values to ensure new config fields are available even when loading older config files.

Scenario: Config file missing new fields

• WHEN config.json exists with { "featureFlags": {} }
• AND the current schema includes a new field defaultAiTool
• THEN getGlobalConfig() returns { featureFlags: {}, defaultAiTool: <default> }
• AND the loaded values take precedence over defaults for fields that exist in both

Scenario: Config file has extra unknown fields

• WHEN config.json contains fields not in the current schema
• THEN the unknown fields are preserved in the returned configuration
• AND no error or warning is raised