feat: add --output json flag for machine-readable output (#67)

## Summary

- Add `--output json` (or `-o json`) flag to CLI commands for
machine-readable output
- For streaming commands (`deploy`, `invoke`), output is JSONL format
(one JSON object per line)
- For list commands, output is a JSON array
- For single-object commands, output is a JSON object
- Update README with JSON output documentation

### Commands with JSON output support:

**Tier 1 (create/acquire operations):**
- `browsers create`
- `browser-pools create`, `acquire`
- `profiles create`
- `extensions upload`
- `proxies create`
- `deploy` (JSONL streaming)

**Tier 2 (list/get operations):**
- `browsers list`, `get`, `view`
- `browser-pools list`, `get`, `update`
- `profiles list`, `get`
- `extensions list`
- `proxies list`, `get`

**Tier 3 (app/invoke/browser sub-operations):**
- `app list`, `history`
- `deploy history`
- `invoke` (JSONL streaming), `history`
- `browsers replays list`, `start`
- `browsers process exec`, `spawn`
- `browsers fs file-info`, `list-files`

## Test plan

- [ ] Test `kernel browsers create -o json` returns valid JSON
- [ ] Test `kernel deploy index.ts -o json` streams JSONL events
- [ ] Test `kernel app list -o json` returns JSON array
- [ ] Test invalid `--output` value shows error message

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Adds machine-readable output across the CLI and documents it.
> 
> - Introduces `--output json`/`-o json` for many commands (apps,
browsers, browser-pools, profiles, extensions, proxies), emitting raw
JSON objects/arrays; suppresses interactive logs when JSON is selected
and validates unsupported values
> - Implements JSONL streaming for `deploy` and `invoke` follow
operations, including terminal-state handling and JSON-formatted errors;
updates `followDeployment`/invocation streaming paths
> - Extends subcommands with new flags and JSON marshalling (e.g.,
`browsers view/get/create`, replays list/start, process exec/spawn, fs
file-info/list-files; browser-pools create/get/update/acquire; app
list/history; deploy history)
> - Minor flag tweak: `browsers replays download` switches to
`-f/--output-file`
> - Updates README with JSON output examples and per-command support
list
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
362c55a. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: rgarcia

README.md

@@ -104,6 +104,32 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
 - `--no-color` - Disable color output
 - `--log-level <level>` - Set log level (trace, debug, info, warn, error, fatal, print)
 
+## JSON Output
+
+Many commands support JSON output for scripting and automation. Use `--output json` or `-o json` to get machine-readable output:
+
+```bash
+# Get browser session details as JSON
+kernel browsers create -o json
+
+# List apps as JSON
+kernel app list -o json
+
+# Deploy with JSONL streaming output (one JSON object per line)
+kernel deploy index.ts -o json
+```
+
+Commands with JSON output support:
+- **Browsers**: `create`, `list`, `get`, `view`
+- **Browser Pools**: `create`, `list`, `get`, `update`, `acquire`
+- **Profiles**: `create`, `list`, `get`
+- **Extensions**: `upload`, `list`
+- **Proxies**: `create`, `list`, `get`
+- **Apps**: `list`, `history`
+- **Deploy**: `deploy` (JSONL streaming), `history`
+- **Invoke**: `invoke` (JSONL streaming), `history`
+- **Browser Sub-commands**: `replays list/start`, `process exec/spawn`, `fs file-info/list-files`
+
 ### Authentication
 
 - `kernel login [--force]` - Login via OAuth 2.0
@@ -134,6 +160,7 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
   - `--force` - Allow overwriting existing version
   - `--env <KEY=VALUE>`, `-e` - Set environment variables (can be used multiple times)
   - `--env-file <file>` - Load environment variables from file (can be used multiple times)
+  - `--output json`, `-o json` - Output JSONL (one JSON object per line for each event)
 
 - `kernel deploy logs <deployment_id>` - Stream logs for a deployment
 
@@ -143,6 +170,7 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
 
 - `kernel deploy history [app_name]` - Show deployment history
   - `--limit <n>` - Max deployments to return (default: 100; 0 = all)
+  - `--output json`, `-o json` - Output raw JSON array
 
 ### App Management
 
@@ -152,14 +180,17 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
   - `--payload <json>`, `-p` - JSON payload for the action
   - `--payload-file <path>`, `-f` - Read JSON payload from a file (use `-` for stdin)
   - `--sync`, `-s` - Invoke synchronously (timeout after 60s)
+  - `--output json`, `-o json` - Output JSONL (one JSON object per line for each event)
 
 - `kernel app list` - List deployed apps
 
   - `--name <app_name>` - Filter by app name
   - `--version <version>` - Filter by version
+  - `--output json`, `-o json` - Output raw JSON array
 
 - `kernel app history <app_name>` - Show deployment history for an app
   - `--limit <n>` - Max deployments to return (default: 100; 0 = all)
+  - `--output json`, `-o json` - Output raw JSON array
 
 ### Logs
 
@@ -172,36 +203,44 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
 ### Browser Management
 
 - `kernel browsers list` - List running browsers
+  - `--output json`, `-o json` - Output raw JSON array
 - `kernel browsers create` - Create a new browser session
   - `-s, --stealth` - Launch browser in stealth mode to avoid detection
   - `-H, --headless` - Launch browser without GUI access
   - `--kiosk` - Launch browser in kiosk mode
   - `--pool-id <id>` - Acquire a browser from the specified pool (mutually exclusive with --pool-name; ignores other session flags)
   - `--pool-name <name>` - Acquire a browser from the pool name (mutually exclusive with --pool-id; ignores other session flags)
+  - `--output json`, `-o json` - Output raw JSON object
   - _Note: When a pool is specified, omit other session configuration flags—pool settings determine profile, proxy, viewport, etc._
 - `kernel browsers delete <id>` - Delete a browser
   - `-y, --yes` - Skip confirmation prompt
 - `kernel browsers view <id>` - Get live view URL for a browser
+  - `--output json`, `-o json` - Output JSON with liveViewUrl
+- `kernel browsers get <id>` - Get detailed browser session info
+  - `--output json`, `-o json` - Output raw JSON object
 
 ### Browser Pools
 
 - `kernel browser-pools list` - List browser pools
-  - `-o, --output json` - Output raw JSON response
+  - `--output json`, `-o json` - Output raw JSON array
 - `kernel browser-pools create` - Create a browser pool
   - `--name <name>` - Optional unique name for the pool
   - `--size <n>` - Number of browsers in the pool (required)
   - `--fill-rate <n>` - Percentage of the pool to fill per minute
   - `--timeout <seconds>` - Idle timeout for browsers acquired from the pool
   - `--stealth`, `--headless`, `--kiosk` - Default pool configuration
   - `--profile-id`, `--profile-name`, `--save-changes`, `--proxy-id`, `--extension`, `--viewport` - Same semantics as `kernel browsers create`
+  - `--output json`, `-o json` - Output raw JSON object
 - `kernel browser-pools get <id-or-name>` - Get pool details
-  - `-o, --output json` - Output raw JSON response
+  - `--output json`, `-o json` - Output raw JSON object
 - `kernel browser-pools update <id-or-name>` - Update pool configuration
   - Same flags as create plus `--discard-all-idle` to discard all idle browsers in the pool and refill at the specified fill rate
+  - `--output json`, `-o json` - Output raw JSON object
 - `kernel browser-pools delete <id-or-name>` - Delete a pool
   - `--force` - Force delete even if browsers are leased
 - `kernel browser-pools acquire <id-or-name>` - Acquire a browser from the pool
   - `--timeout <seconds>` - Acquire timeout before returning 204
+  - `--output json`, `-o json` - Output raw JSON object
 - `kernel browser-pools release <id-or-name>` - Release a browser back to the pool
   - `--session-id <id>` - Browser session ID to release (required)
   - `--reuse` - Reuse the browser instance (default: true)
@@ -218,12 +257,14 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
 ### Browser Replays
 
 - `kernel browsers replays list <id>` - List replays for a browser
+  - `--output json`, `-o json` - Output raw JSON array
 - `kernel browsers replays start <id>` - Start a replay recording
   - `--framerate <fps>` - Recording framerate (fps)
   - `--max-duration <seconds>` - Maximum duration in seconds
+  - `--output json`, `-o json` - Output raw JSON object
 - `kernel browsers replays stop <id> <replay-id>` - Stop a replay recording
 - `kernel browsers replays download <id> <replay-id>` - Download a replay video
-  - `-o, --output <path>` - Output file path for the replay video
+  - `-f, --output-file <path>` - Output file path for the replay video
 
 ### Browser Process Control
 
@@ -234,13 +275,15 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
   - `--timeout <seconds>` - Timeout in seconds
   - `--as-user <user>` - Run as user
   - `--as-root` - Run as root
+  - `--output json`, `-o json` - Output raw JSON object
 - `kernel browsers process spawn <id> [--] [command...]` - Execute a command asynchronously
   - `--command <cmd>` - Command to execute (optional; if omitted, trailing args are executed via /bin/bash -c)
   - `--args <args>` - Command arguments
   - `--cwd <path>` - Working directory
   - `--timeout <seconds>` - Timeout in seconds
   - `--as-user <user>` - Run as user
   - `--as-root` - Run as root
+  - `--output json`, `-o json` - Output raw JSON object
 - `kernel browsers process kill <id> <process-id>` - Send a signal to a process
   - `--signal <signal>` - Signal to send: TERM, KILL, INT, HUP (default: TERM)
 - `kernel browsers process status <id> <process-id>` - Get process status
@@ -262,8 +305,10 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
   - `-o, --output <path>` - Output zip file path
 - `kernel browsers fs file-info <id>` - Get file or directory info
   - `--path <path>` - Absolute file or directory path (required)
+  - `--output json`, `-o json` - Output raw JSON object
 - `kernel browsers fs list-files <id>` - List files in a directory
   - `--path <path>` - Absolute directory path (required)
+  - `--output json`, `-o json` - Output raw JSON array
 - `kernel browsers fs move <id>` - Move or rename a file or directory
   - `--src <path>` - Absolute source path (required)
   - `--dest <path>` - Absolute destination path (required)
@@ -344,8 +389,10 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
 ### Extension Management
 
 - `kernel extensions list` - List all uploaded extensions
+  - `--output json`, `-o json` - Output raw JSON array
 - `kernel extensions upload <directory>` - Upload an unpacked browser extension directory
   - `--name <name>` - Optional unique extension name
+  - `--output json`, `-o json` - Output raw JSON object
 - `kernel extensions download <id-or-name>` - Download an extension archive
   - `--to <directory>` - Output directory (required)
 - `kernel extensions download-web-store <url>` - Download an extension from the Chrome Web Store
@@ -357,8 +404,11 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
 ### Proxy Management
 
 - `kernel proxies list` - List proxy configurations
+  - `--output json`, `-o json` - Output raw JSON array
 - `kernel proxies get <id>` - Get a proxy configuration by ID
+  - `--output json`, `-o json` - Output raw JSON object
 - `kernel proxies create` - Create a new proxy configuration
+  - `--output json`, `-o json` - Output raw JSON object
 
   - `--name <name>` - Proxy configuration name
   - `--type <type>` - Proxy type: datacenter, isp, residential, mobile, custom (required)

cmd/app.go

@@ -1,6 +1,7 @@
 package cmd
 
 import (
+	"encoding/json"
 	"fmt"
 	"strings"
 
@@ -44,9 +45,11 @@ func init() {
 	appListCmd.Flags().Int("limit", 20, "Max apps to return (default 20)")
 	appListCmd.Flags().Int("per-page", 20, "Items per page (alias of --limit)")
 	appListCmd.Flags().Int("page", 1, "Page number (1-based)")
+	appListCmd.Flags().StringP("output", "o", "", "Output format: json for raw API response")
 
 	// Limit rows returned for app history (0 = all)
 	appHistoryCmd.Flags().Int("limit", 20, "Max deployments to return (default 20)")
+	appHistoryCmd.Flags().StringP("output", "o", "", "Output format: json for raw API response")
 }
 
 func runAppList(cmd *cobra.Command, args []string) error {
@@ -56,6 +59,11 @@ func runAppList(cmd *cobra.Command, args []string) error {
 	lim, _ := cmd.Flags().GetInt("limit")
 	perPage, _ := cmd.Flags().GetInt("per-page")
 	page, _ := cmd.Flags().GetInt("page")
+	output, _ := cmd.Flags().GetString("output")
+
+	if output != "" && output != "json" {
+		return fmt.Errorf("unsupported --output value: use 'json'")
+	}
 
 	// Determine pagination inputs: prefer page/per-page if provided; else map legacy --limit
 	usePager := cmd.Flags().Changed("per-page") || cmd.Flags().Changed("page")
@@ -73,7 +81,9 @@ func runAppList(cmd *cobra.Command, args []string) error {
 		page = 1
 	}
 
-	pterm.Debug.Println("Fetching deployed applications...")
+	if output != "json" {
+		pterm.Debug.Println("Fetching deployed applications...")
+	}
 
 	params := kernel.AppListParams{}
 	if appName != "" {
@@ -92,6 +102,19 @@ func runAppList(cmd *cobra.Command, args []string) error {
 		return nil
 	}
 
+	if output == "json" {
+		if apps == nil || len(apps.Items) == 0 {
+			fmt.Println("[]")
+			return nil
+		}
+		bs, err := json.MarshalIndent(apps.Items, "", "  ")
+		if err != nil {
+			return err
+		}
+		fmt.Println(string(bs))
+		return nil
+	}
+
 	if apps == nil || len(apps.Items) == 0 {
 		pterm.Info.Println("No applications found")
 		return nil
@@ -193,8 +216,15 @@ func runAppHistory(cmd *cobra.Command, args []string) error {
 	client := getKernelClient(cmd)
 	appName := args[0]
 	lim, _ := cmd.Flags().GetInt("limit")
+	output, _ := cmd.Flags().GetString("output")
 
-	pterm.Debug.Printf("Fetching deployment history for app '%s'...\n", appName)
+	if output != "" && output != "json" {
+		return fmt.Errorf("unsupported --output value: use 'json'")
+	}
+
+	if output != "json" {
+		pterm.Debug.Printf("Fetching deployment history for app '%s'...\n", appName)
+	}
 
 	params := kernel.DeploymentListParams{}
 	if appName != "" {
@@ -207,6 +237,19 @@ func runAppHistory(cmd *cobra.Command, args []string) error {
 		return nil
 	}
 
+	if output == "json" {
+		if deployments == nil || len(deployments.Items) == 0 {
+			fmt.Println("[]")
+			return nil
+		}
+		bs, err := json.MarshalIndent(deployments.Items, "", "  ")
+		if err != nil {
+			return err
+		}
+		fmt.Println(string(bs))
+		return nil
+	}
+
 	if deployments == nil || len(deployments.Items) == 0 {
 		pterm.Info.Println("No deployments found for this application")
 		return nil