docs: complete CLI documentation with config and completions commands

- Added hatch config command documentation (show, set, get, init)
- Added hatch completions command documentation (bash, zsh, fish, powershell)
- Documented HATCH_FORMAT, NO_COLOR, PORT environment variables
- Updated cli-quick-reference.md with new commands and env vars
- Configuration file locations and priority order documented

Co-Authored-By: Paperclip <noreply@paperclip.ing>

docs/engineering/cli-quick-reference.md

@@ -21,6 +21,9 @@ sudo mv hatch /usr/local/bin/
 | `hatch mock set <endpoint>` | Configure mock | `hatch mock set api -status 200 -body '{}'` |
 | `hatch doc generate <endpoint>` | Generate OpenAPI | `hatch doc generate api > openapi.json` |
 | `hatch version` | Print version | `hatch version` |
+| `hatch config show` | Show config | `hatch config show` |
+| `hatch config set <k> <v>` | Set config | `hatch config set format table` |
+| `hatch completions [shell]` | Shell completions | `hatch completions bash` |
 
 ## Common Flags
 
@@ -40,8 +43,23 @@ sudo mv hatch /usr/local/bin/
 | Variable | Description | Default |
 |----------|-------------|---------|
 | `HATCH_URL` | Server URL | `http://localhost:8080` |
+| `HATCH_FORMAT` | Output format | `json` |
+| `NO_COLOR` | Disable colors | not set |
 | `PORT` | Server port | `8080` |
 
+## Configuration File
+
+- **Linux**: `~/.config/hatch/config.json`
+- **macOS**: `~/Library/Application Support/hatch/config.json`
+
+```bash
+# Initialize config
+hatch config init
+
+# View config
+hatch config show
+```
+
 ## Quick Examples
 
 ### Capture a Webhook
@@ -99,8 +117,8 @@ hatch doc generate api/posts > posts-api.json
 | 1 | General error |
 | 2 | Invalid arguments |
 | 3 | Network error |
-| 4 | Auth error |
-| 5 | Not found |
+| 4 | Server error |
+| 5 | Config error |
 
 ## Troubleshooting
 

docs/engineering/cli.md

@@ -51,14 +51,28 @@ docker run --rm -it ghcr.io/elfoundation/hatch:latest --help
 | Variable | Description | Default |
 |----------|-------------|---------|
 | `HATCH_URL` | Hatch server URL | `http://localhost:8080` |
+| `HATCH_FORMAT` | Output format (`json`, `table`, `compact`) | `json` |
+| `NO_COLOR` | Disable colored output | not set |
+| `PORT` | Server listening port | `8080` |
 
 ### Global Options
 
 All commands support these flags:
 
 - `-h, --help`: Show help for the command
+- `-output FORMAT`: Output format (`json`, `table`, `compact`)
 - `version`: Print version information
 
+### Configuration File
+
+Hatch stores configuration in a JSON file. The location depends on your OS:
+
+- **Linux/Unix**: `~/.config/hatch/config.json`
+- **macOS**: `~/Library/Application Support/hatch/config.json`
+- **XDG**: `$XDG_CONFIG_HOME/hatch/config.json`
+
+Priority: Environment variables > Config file > Defaults
+
 ## Commands
 
 ### `hatch serve`
@@ -73,6 +87,16 @@ hatch serve
 PORT=9090 hatch serve
 ```
 
+Start the Hatch server. This is the default command when no subcommand is specified.
+
+```bash
+# Start server on default port (8080)
+hatch serve
+
+# Start with custom port (use environment variable)
+PORT=9090 hatch serve
+```
+
 ### `hatch capture <url>`
 
 Send a request to an endpoint and store it in Hatch.
@@ -398,11 +422,95 @@ chmod +x hatch
 sudo mv hatch /usr/local/bin/
 ```
 
+### `hatch config`
+
+Manage hatch configuration.
+
+**Subcommands:**
+
+| Subcommand | Description |
+|------------|-------------|
+| `config show` | Display current configuration |
+| `config set <key> <value>` | Set a configuration value |
+| `config get <key>` | Get a configuration value |
+| `config init` | Create default config file |
+
+**Configurable Keys:**
+
+| Key | Description | Valid Values |
+|-----|-------------|--------------|
+| `server_url` | Hatch server URL | Any valid URL |
+| `format` | Output format | `json`, `table`, `compact` |
+| `no_color` | Disable colors | `true`, `false`, `1`, `0` |
+| `timeout` | Request timeout (seconds) | Positive integer |
+
+**Examples:**
+
+```bash
+# Show current configuration
+hatch config show
+
+# Set server URL
+hatch config set server_url https://hatch.example.com
+
+# Set output format to table
+hatch config set format table
+
+# Disable colored output
+hatch config set no_color true
+
+# Set timeout to 60 seconds
+hatch config set timeout 60
+
+# Get a specific value
+hatch config get server_url
+
+# Initialize config file with defaults
+hatch config init
+```
+
+### `hatch completions`
+
+Generate shell completions for hatch.
+
+**Syntax:**
+
+```bash
+hatch completions [shell]
+```
+
+**Supported Shells:**
+
+| Shell | Command |
+|-------|----------|
+| Bash | `hatch completions bash` |
+| Zsh | `hatch completions zsh` |
+| Fish | `hatch completions fish` |
+| PowerShell | `hatch completions powershell` |
+
+**Installation:**
+
+```bash
+# Bash - add to ~/.bashrc
+hatch completions bash >> ~/.bashrc
+
+# Zsh - add to ~/.zshrc  
+hatch completions zsh >> ~/.zshrc
+
+# Fish - save to completions directory
+hatch completions fish > ~/.config/fish/completions/hatch.fish
+
+# PowerShell - add to profile
+hatch completions powershell >> $PROFILE
+```
+
 ## Environment Variables Reference
 
 | Variable | Description | Default | Example |
 |----------|-------------|---------|---------|
 | `HATCH_URL` | Hatch server URL | `http://localhost:8080` | `https://hatch.example.com` |
+| `HATCH_FORMAT` | Output format | `json` | `table`, `compact` |
+| `NO_COLOR` | Disable colored output | not set | `1` |
 | `PORT` | Server listening port | `8080` | `9090` |
 
 ## Exit Codes