feat(cli): add openspec config command for global configuration management

openspec/changes/add-config-command/design.md

@@ -0,0 +1,89 @@
+## Context
+
+The `global-config` spec defines how OpenSpec reads/writes `config.json`, but users currently must edit it by hand. This command provides a CLI interface to that config.
+
+## Goals / Non-Goals
+
+**Goals:**
+- Provide a discoverable CLI for config management
+- Support scripting with machine-readable output
+- Validate config changes with zod schema
+- Handle nested keys gracefully
+
+**Non-Goals:**
+- Project-local config (reserved for future via `--scope` flag)
+- Complex queries (JSONPath, filtering)
+- Config file format migration
+
+## Decisions
+
+### Key Naming: camelCase with Dot Notation
+
+**Decision:** Keys use camelCase matching the JSON structure, with dot notation for nesting.
+
+**Rationale:**
+- Matches the actual JSON keys (no translation layer)
+- Dot notation is intuitive and widely used (lodash, jq, kubectl)
+- Avoids complexity of supporting multiple casing styles
+
+**Examples:**
+```bash
+openspec config get featureFlags              # Returns object
+openspec config get featureFlags.experimental # Returns nested value
+openspec config set featureFlags.newFlag true
+```
+
+### Type Coercion: Auto-detect with `--string` Override
+
+**Decision:** Parse values automatically; provide `--string` flag to force string storage.
+
+**Rationale:**
+- Most intuitive for common cases (`true`, `false`, `123`)
+- Explicit override for edge cases (storing literal string "true")
+- Follows npm/yarn config patterns
+
+**Coercion rules:**
+| Input | Stored As |
+|-------|-----------|
+| `true`, `false` | boolean |
+| Numeric string (`123`, `3.14`) | number |
+| Everything else | string |
+| Any value with `--string` | string |
+
+### Output Format: Raw by Default
+
+**Decision:** `get` prints raw value only. `list` prints YAML-like format by default, JSON with `--json`.
+
+**Rationale:**
+- Raw output enables piping: `VAR=$(openspec config get key)`
+- YAML-like is human-readable for inspection
+- JSON for automation/scripting
+
+### Schema Validation: Zod with Unknown Field Passthrough
+
+**Decision:** Use zod for validation but preserve unknown fields per `global-config` spec.
+
+**Rationale:**
+- Type safety for known fields
+- Forward compatibility (old CLI doesn't break new config)
+- Follows existing `global-config` spec requirement
+
+### Reserved Flag: `--scope`
+
+**Decision:** Reserve `--scope global|project` but only implement `global` initially.
+
+**Rationale:**
+- Avoids breaking change if project-local config is added later
+- Clear error message if someone tries `--scope project`
+
+## Risks / Trade-offs
+
+| Risk | Mitigation |
+|------|------------|
+| Dot notation conflicts with keys containing dots | Rare in practice; document limitation |
+| Type coercion surprises | `--string` escape hatch; document rules |
+| $EDITOR not set | Check and provide helpful error message |
+
+## Open Questions
+
+None - design is straightforward.

openspec/changes/add-config-command/proposal.md

@@ -1,39 +1,60 @@
 ## Why
 
-Users need a way to view and modify their global OpenSpec settings without manually editing JSON files. The `add-global-config-dir` change provides the foundation, but there's no user-facing interface to interact with the config. A dedicated `openspec config` command provides discoverability and ease of use.
+Users need a way to view and modify their global OpenSpec settings without manually editing JSON files. The `global-config` spec provides the foundation, but there's no user-facing interface to interact with the config. A dedicated `openspec config` command provides discoverability and ease of use.
 
 ## What Changes
 
 Add `openspec config` subcommand with the following operations:
 
 ```bash
-openspec config path                    # Show config file location
-openspec config list                    # Show all current settings
-openspec config get <key>               # Get a specific value
-openspec config set <key> <value>       # Set a value
-openspec config reset [key]             # Reset to defaults (all or specific key)
+openspec config path                          # Show config file location
+openspec config list [--json]                 # Show all current settings
+openspec config get <key>                     # Get a specific value (raw, scriptable)
+openspec config set <key> <value> [--string]  # Set a value (auto-coerce types)
+openspec config unset <key>                   # Remove a key (revert to default)
+openspec config reset --all [-y]              # Reset everything to defaults
+openspec config edit                          # Open config in $EDITOR
 ```
 
+**Key design decisions:**
+- **Key naming**: Use camelCase to match JSON structure (e.g., `featureFlags.someFlag`)
+- **Nested keys**: Support dot notation for nested access
+- **Type coercion**: Auto-detect types by default; `--string` flag forces string storage
+- **Scriptable output**: `get` prints raw value only (no labels) for easy piping
+- **Zod validation**: Use zod for config schema validation and type safety
+- **Future-proofing**: Reserve `--scope global|project` flag for potential project-local config
+
 **Example usage:**
 ```bash
 $ openspec config path
 /Users/me/.config/openspec/config.json
 
 $ openspec config list
-enableTelemetry: true
 featureFlags: {}
 
-$ openspec config set enableTelemetry false
-Set enableTelemetry = false
+$ openspec config set featureFlags.enableTelemetry false
+Set featureFlags.enableTelemetry = false
 
-$ openspec config get enableTelemetry
+$ openspec config get featureFlags.enableTelemetry
 false
+
+$ openspec config list --json
+{
+  "featureFlags": {}
+}
+
+$ openspec config unset featureFlags.enableTelemetry
+Unset featureFlags.enableTelemetry (reverted to default)
+
+$ openspec config edit
+# Opens $EDITOR with config.json
 ```
 
 ## Impact
 
 - Affected specs: New `cli-config` capability
 - Affected code:
   - New `src/commands/config.ts`
+  - New `src/core/config-schema.ts` (zod schema)
   - Update CLI entry point to register config command
-- Dependencies: Requires `add-global-config-dir` to be implemented first
+- Dependencies: Requires `global-config` spec (already implemented)

openspec/changes/add-config-command/specs/cli-config/spec.md

@@ -0,0 +1,213 @@
+# cli-config Specification
+
+## Purpose
+
+Provide a CLI interface for viewing and modifying global OpenSpec configuration. Enables users to manage settings without manually editing JSON files, with support for scripting and automation.
+
+## ADDED Requirements
+
+### Requirement: Command Structure
+
+The config command SHALL provide subcommands for all configuration operations.
+
+#### Scenario: Available subcommands
+
+- **WHEN** user executes `openspec config --help`
+- **THEN** display available subcommands:
+  - `path` - Show config file location
+  - `list` - Show all current settings
+  - `get <key>` - Get a specific value
+  - `set <key> <value>` - Set a value
+  - `unset <key>` - Remove a key (revert to default)
+  - `reset` - Reset configuration to defaults
+  - `edit` - Open config in editor
+
+### Requirement: Config Path
+
+The config command SHALL display the config file location.
+
+#### Scenario: Show config path
+
+- **WHEN** user executes `openspec config path`
+- **THEN** print the absolute path to the config file
+- **AND** exit with code 0
+
+### Requirement: Config List
+
+The config command SHALL display all current configuration values.
+
+#### Scenario: List config in human-readable format
+
+- **WHEN** user executes `openspec config list`
+- **THEN** display all config values in YAML-like format
+- **AND** show nested objects with indentation
+
+#### Scenario: List config as JSON
+
+- **WHEN** user executes `openspec config list --json`
+- **THEN** output the complete config as valid JSON
+- **AND** output only JSON (no additional text)
+
+### Requirement: Config Get
+
+The config command SHALL retrieve specific configuration values.
+
+#### Scenario: Get top-level key
+
+- **WHEN** user executes `openspec config get <key>` with a valid top-level key
+- **THEN** print the raw value only (no labels or formatting)
+- **AND** exit with code 0
+
+#### Scenario: Get nested key with dot notation
+
+- **WHEN** user executes `openspec config get featureFlags.someFlag`
+- **THEN** traverse the nested structure using dot notation
+- **AND** print the value at that path
+
+#### Scenario: Get non-existent key
+
+- **WHEN** user executes `openspec config get <key>` with a key that does not exist
+- **THEN** print nothing (empty output)
+- **AND** exit with code 1
+
+#### Scenario: Get object value
+
+- **WHEN** user executes `openspec config get <key>` where the value is an object
+- **THEN** print the object as JSON
+
+### Requirement: Config Set
+
+The config command SHALL set configuration values with automatic type coercion.
+
+#### Scenario: Set string value
+
+- **WHEN** user executes `openspec config set <key> <value>`
+- **AND** value does not match boolean or number patterns
+- **THEN** store value as a string
+- **AND** display confirmation message
+
+#### Scenario: Set boolean value
+
+- **WHEN** user executes `openspec config set <key> true` or `openspec config set <key> false`
+- **THEN** store value as boolean (not string)
+- **AND** display confirmation message
+
+#### Scenario: Set numeric value
+
+- **WHEN** user executes `openspec config set <key> <value>`
+- **AND** value is a valid number (integer or float)
+- **THEN** store value as number (not string)
+
+#### Scenario: Force string with --string flag
+
+- **WHEN** user executes `openspec config set <key> <value> --string`
+- **THEN** store value as string regardless of content
+- **AND** this allows storing literal "true" or "123" as strings
+
+#### Scenario: Set nested key
+
+- **WHEN** user executes `openspec config set featureFlags.newFlag true`
+- **THEN** create intermediate objects if they don't exist
+- **AND** set the value at the nested path
+
+### Requirement: Config Unset
+
+The config command SHALL remove configuration overrides.
+
+#### Scenario: Unset existing key
+
+- **WHEN** user executes `openspec config unset <key>`
+- **AND** the key exists in the config
+- **THEN** remove the key from the config file
+- **AND** the value reverts to its default
+- **AND** display confirmation message
+
+#### Scenario: Unset non-existent key
+
+- **WHEN** user executes `openspec config unset <key>`
+- **AND** the key does not exist in the config
+- **THEN** display message indicating key was not set
+- **AND** exit with code 0
+
+### Requirement: Config Reset
+
+The config command SHALL reset configuration to defaults.
+
+#### Scenario: Reset all with confirmation
+
+- **WHEN** user executes `openspec config reset --all`
+- **THEN** prompt for confirmation before proceeding
+- **AND** if confirmed, delete the config file or reset to defaults
+- **AND** display confirmation message
+
+#### Scenario: Reset all with -y flag
+
+- **WHEN** user executes `openspec config reset --all -y`
+- **THEN** reset without prompting for confirmation
+
+#### Scenario: Reset without --all flag
+
+- **WHEN** user executes `openspec config reset` without `--all`
+- **THEN** display error indicating `--all` is required
+- **AND** exit with code 1
+
+### Requirement: Config Edit
+
+The config command SHALL open the config file in the user's editor.
+
+#### Scenario: Open editor successfully
+
+- **WHEN** user executes `openspec config edit`
+- **AND** `$EDITOR` or `$VISUAL` environment variable is set
+- **THEN** open the config file in that editor
+- **AND** create the config file with defaults if it doesn't exist
+- **AND** wait for the editor to close before returning
+
+#### Scenario: No editor configured
+
+- **WHEN** user executes `openspec config edit`
+- **AND** neither `$EDITOR` nor `$VISUAL` is set
+- **THEN** display error message suggesting to set `$EDITOR`
+- **AND** exit with code 1
+
+### Requirement: Key Naming Convention
+
+The config command SHALL use camelCase keys matching the JSON structure.
+
+#### Scenario: Keys match JSON structure
+
+- **WHEN** accessing configuration keys via CLI
+- **THEN** use camelCase matching the actual JSON property names
+- **AND** support dot notation for nested access (e.g., `featureFlags.someFlag`)
+
+### Requirement: Schema Validation
+
+The config command SHALL validate configuration writes against the config schema using zod, while allowing unknown fields for forward compatibility.
+
+#### Scenario: Unknown key accepted
+
+- **WHEN** user executes `openspec config set someFutureKey 123`
+- **THEN** the value is saved successfully
+- **AND** exit with code 0
+
+#### Scenario: Invalid feature flag value rejected
+
+- **WHEN** user executes `openspec config set featureFlags.someFlag notABoolean`
+- **THEN** display a descriptive error message
+- **AND** do not modify the config file
+- **AND** exit with code 1
+
+### Requirement: Reserved Scope Flag
+
+The config command SHALL reserve the `--scope` flag for future extensibility.
+
+#### Scenario: Scope flag defaults to global
+
+- **WHEN** user executes any config command without `--scope`
+- **THEN** operate on global configuration (default behavior)
+
+#### Scenario: Project scope not yet implemented
+
+- **WHEN** user executes `openspec config --scope project <subcommand>`
+- **THEN** display error message: "Project-local config is not yet implemented"
+- **AND** exit with code 1