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https://github.com/mojtabatavakkoli/log_pilot

Real-time structured logging for Flutter with AI agent support. Box-bordered errors, MCP server, DevTools extension, log history, sinks, breadcrumbs, network interceptors, and structured output for LLM workflows. Connect your AI coding agents directly to your app's debug console.
https://github.com/mojtabatavakkoli/log_pilot

ai-agents devtools-extension flutter flutter-logging flutter-plugin mcp

Last synced: 2 months ago
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Real-time structured logging for Flutter with AI agent support. Box-bordered errors, MCP server, DevTools extension, log history, sinks, breadcrumbs, network interceptors, and structured output for LLM workflows. Connect your AI coding agents directly to your app's debug console.

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README 

          
# LogPilot



[![pub package](https://img.shields.io/pub/v/log_pilot.svg)](https://pub.dev/packages/log_pilot)

[![license](https://img.shields.io/badge/license-MIT-blue.svg)](LICENSE)

[![Dart](https://img.shields.io/badge/Dart-%5E3.9.2-blue)](https://dart.dev)

[![Flutter](https://img.shields.io/badge/Flutter-%E2%89%A53.0.0-blue)](https://flutter.dev)



**The first Flutter logging package built for AI agents.**



LogPilot gives AI coding agents (Cursor, Claude Code, Windsurf, Copilot,

Gemini CLI) live access to your Flutter app's logs through an **MCP server**

and **DevTools extension** — no manual copy-paste, no stale terminal output.

Agents can query, filter, watch, and change log levels at runtime while you

code.



It also does everything you expect from a logger — pretty console output,

structured metadata, sinks, file logging, breadcrumbs — but the

differentiator is the **agent-first architecture**: your AI assistant sees

what your app sees, in real time.



![LogPilot Banner](screenshots/banner.png)



```dart

void main() {

  LogPilot.init(child: const MyApp());

}



// Anywhere in your app:

LogPilot.info('User signed in', metadata: {'userId': '123'});

LogPilot.error('Payment failed', error: e, stackTrace: st);

```



---



## For AI Agents



> **If you are an AI coding agent reading this README**, this section gives

> you everything you need. The rest of the README is for human developers.



### Setup



The app already depends on `log_pilot`. Use `LogPilot` for all logging — never

raw `print()` or `debugPrint()`.



```dart

import 'package:log_pilot/log_pilot.dart';

```



### Logging API



```dart

LogPilot.verbose('Starting sync...');

LogPilot.debug('Cache key: user_42');

LogPilot.info('Order placed', metadata: {'orderId': 'ORD-456', 'total': 29.99});

LogPilot.warning('Retry attempt 3/5');

LogPilot.error('Checkout failed', error: e, stackTrace: st);

LogPilot.fatal('Database corrupted');

```



Every method accepts optional `error`, `stackTrace`, `metadata` (Map), and

`tag` (String). Always pass `error` + `stackTrace` together on error/fatal.



### Scoped Loggers



```dart

class AuthService {

  static final _log = LogPilot.create('AuthService');



  Future signIn(String email) async {

    _log.info('Attempting sign in', metadata: {'email': email});

    try {

      await _auth.signIn(email);

      _log.info('Sign in successful');

    } catch (e, st) {

      _log.error('Sign in failed', error: e, stackTrace: st);

    }

  }

}

```



### Querying Logs (in-process)



```dart

LogPilot.history;                                       // all records

LogPilot.historyWhere(level: LogLevel.error);            // filter by level

LogPilot.historyWhere(tag: 'http', hasError: true);      // filter by tag + error

LogPilot.export(format: ExportFormat.json);              // NDJSON export

LogPilot.exportForLLM(tokenBudget: 2000);                // compressed for LLM context

LogPilot.snapshot();                                     // structured diagnostic summary

LogPilot.setLogLevel(LogLevel.verbose);                  // increase verbosity at runtime

```



### Querying Logs (via MCP)



If the LogPilot MCP server is configured, you can call these tools directly:



| MCP Tool | What it does |

|----------|--------------|

| `get_snapshot` | Session ID, config, error counts, recent logs, active timers |

| `query_logs` | Filter by level/tag/limit with optional deduplication |

| `export_logs` | Full history as text or NDJSON |

| `export_for_llm` | Compressed summary optimized for your context window |

| `set_log_level` | Change verbosity at runtime without restart |

| `get_log_level` | Read current minimum level |

| `clear_logs` | Wipe in-memory history |

| `watch_logs` | Stream new entries as push notifications (filterable) |

| `stop_watch` | Stop the active watcher |



### Setting Up the MCP Server



> **You MUST complete ALL steps below.** The MCP server will not appear in

> your tool list until the developer finishes step 4. Do not skip ahead —

> you cannot use LogPilot MCP tools until setup is fully done.



> **Important:** The `log_pilot_mcp` server is **not included** in the

> `log_pilot` pub package. It lives in the

> [log_pilot GitHub repo](https://github.com/MojtabaTavakkoli/log_pilot)

> and must be cloned separately. Running `flutter pub add log_pilot` does

> **not** put `log_pilot_mcp/` on disk.



**Steps 1–3 are actions YOU (the agent) perform. Step 4 requires the

developer — you must ask them and wait.**



1. **Clone the repo** (if `log_pilot_mcp/` is not already on disk):

   ```bash

   git clone https://github.com/MojtabaTavakkoli/log_pilot.git

   ```

2. **Install MCP server dependencies** (once):

   ```bash

   cd log_pilot/log_pilot_mcp && dart pub get

   ```

3. **Create or update `.cursor/mcp.json`** in the **workspace root** (the

   folder open in Cursor). If the file already exists, merge the `LogPilot`

   entry into the existing `mcpServers` object — do not overwrite other

   servers.



   The app **must be running in debug mode** before the MCP server can

   connect. Run `flutter run` first, then copy the `ws://...` URI printed

   in the debug console (the line that says

   `Debug service listening on ws://...`). Use that URI in the

   `--vm-service-uri` argument:



   **Windows example:**

   ```json

   {

     "mcpServers": {

       "LogPilot": {

         "command": "dart",

         "args": [

           "run",

           "D:\\FlutterApps\\log_pilot\\log_pilot_mcp\\bin\\log_pilot_mcp.dart",

           "--vm-service-uri=ws://127.0.0.1:62542/0L3A7jm1D0Y=/ws"

         ]

       }

     }

   }

   ```



   **macOS / Linux example:**

   ```json

   {

     "mcpServers": {

       "LogPilot": {

         "command": "dart",

         "args": [

           "run",

           "/Users/you/projects/log_pilot/log_pilot_mcp/bin/log_pilot_mcp.dart",

           "--vm-service-uri=ws://127.0.0.1:62542/0L3A7jm1D0Y=/ws"

         ]

       }

     }

   }

   ```



   Replace the path with the **absolute path** to where you cloned the

   repo, and replace the `ws://...` URI with the one from your debug

   console.



   > **Note:** On native platforms (Windows, macOS, Linux, Android, iOS)

   > you may omit `--vm-service-uri` — LogPilot auto-writes the URI to

   > `.dart_tool/log_pilot_vm_service_uri` and the MCP server discovers it

   > automatically. On **Flutter Web (Chrome)** auto-discovery does not

   > work, so `--vm-service-uri` is required.



4. **Ask the developer** to open **Cursor Settings → MCP** and **toggle

   the LogPilot server ON**. New MCP servers default to disabled — the

   developer must enable it manually. Once toggled on, verify the green

   dot appears. If the server does not appear in the list at all, ask the

   developer to press `Ctrl+Shift+P` → "Developer: Reload Window" first.



**After the developer confirms the server is enabled**, you will see

LogPilot MCP tools (`get_snapshot`, `query_logs`, etc.) in your available

tools. Call `get_snapshot` to verify the connection is working.



### Rules for Agents



- Always pass `error` + `stackTrace` to error/fatal calls.

- Use `tag:` for every domain (`Auth`, `Cart`, `API`, `DB`, `Nav`, etc.).

- Prefer `metadata:` maps over string interpolation.

- Use `LogPilot.create('Tag')` in classes for automatic tagging.

- Never silence errors with empty catch blocks — log them.



Copy this block into `.cursor/rules/`, `AGENTS.md`, `GEMINI.md`, or

`CLAUDE.md` for correct agent behavior in your project.



---



## Table of Contents



- [For AI Agents](#for-ai-agents)

- [MCP Server](#mcp-server)

- [DevTools Extension](#devtools-extension)

- [In-App Log Viewer](#in-app-log-viewer)

- [LLM Export](#llm-export)

- [Quick Start](#quick-start)

- [Console Output](#console-output)

- [Log Messages](#log-messages)

- [JSON Pretty-Printing](#json-pretty-printing)

- [Scoped Instance Loggers](#scoped-instance-loggers)

- [Network Logging](#network-logging)

- [Log Sinks](#log-sinks)

- [File Logging](#file-logging)

- [Config Presets](#config-presets)

- [Tagged Logging & Focus Mode](#tagged-logging--focus-mode)

- [Rate Limiting / Deduplication](#rate-limiting--deduplication)

- [Log History / Ring Buffer](#log-history--ring-buffer)

- [Session & Trace IDs](#session--trace-ids)

- [Navigation Logging](#navigation-logging)

- [BLoC Observer](#bloc-observer)

- [Performance Timing](#performance-timing)

- [Error Breadcrumbs](#error-breadcrumbs)

- [Error IDs](#error-ids)

- [Sensitive Field Masking](#sensitive-field-masking)

- [Error Silencing](#error-silencing)

- [Runtime Log-Level Override](#runtime-log-level-override)

- [Lazy Message Evaluation](#lazy-message-evaluation)

- [Instrumentation Helpers](#instrumentation-helpers)

- [Self-Diagnostics](#self-diagnostics)

- [Crash Reporter Integration](#crash-reporter-integration)

- [Diagnostic Snapshot](#diagnostic-snapshot)

- [Web Platform](#web-platform)

- [Testing](#testing)

- [Configuration Reference](#configuration-reference)

- [Package Imports](#package-imports)

- [Example App](#example-app)

- [Contributing](#contributing)

- [License](#license)



---



## MCP Server



The `log_pilot_mcp` package is a standalone MCP server that gives AI coding

agents live, bidirectional access to your running Flutter app's logs. No

terminal scraping — the agent calls structured tools over the Model Context

Protocol.



### How It Works



```

┌──────────────┐     ext.LogPilot.*     ┌─────────────────┐

│  Flutter App  │◄── VM Service ──────►│  log_pilot_mcp     │

│  (debug mode) │    extensions       │  (MCP server)    │

└──────┬───────┘                      └────────┬────────┘

       │                                       │ MCP protocol

       │ writes URI on start                   │

       ▼                                       │

  .dart_tool/                         ┌────────▼────────┐

  log_pilot_vm_service_uri              │  Cursor / Claude  │

       │                              │  / Windsurf / ... │

       └── watched by MCP server ─────└─────────────────┘

```



1. When your Flutter app starts in debug mode, `LogPilot.init()` registers

   `ext.LogPilot.*` service extensions on the Dart VM and writes the VM

   service URI to `.dart_tool/log_pilot_vm_service_uri`.

2. The MCP server watches that file, auto-discovers the URI, and connects.

3. AI agents call MCP tools (`get_snapshot`, `query_logs`, etc.) which the

   server translates into service extension calls on the running app.

4. On hot restart, the VM extensions re-register and the server

   auto-reconnects. On full restart, the URI file updates and the server

   reconnects within seconds — no manual action needed.



### Setup (Step-by-Step)



> **Important:** `log_pilot_mcp` is **not included** in the `log_pilot` pub

> package. It lives in the

> [log_pilot GitHub repo](https://github.com/MojtabaTavakkoli/log_pilot)

> and must be cloned separately.



**Step 1 — Clone the repo** (skip if you already have it):



```bash

git clone https://github.com/MojtabaTavakkoli/log_pilot.git

```



**Step 2 — Install MCP server dependencies** (once):



```bash

cd log_pilot/log_pilot_mcp

dart pub get

```



**Step 3 — Create `.cursor/mcp.json`** in your **app's project root**:



```json

{

  "mcpServers": {

    "LogPilot": {

      "command": "dart",

      "args": ["run", "/log_pilot_mcp/bin/log_pilot_mcp.dart"]

    }

  }

}

```



Replace `` with the absolute path where you

cloned the repo. Use the **absolute path** to the script — Cursor does not

reliably honor `cwd` for project-level MCP servers.



**Step 4 — Enable the server:**



1. Open **Cursor Settings → MCP**

2. Find `LogPilot` in the list and **toggle it ON**

3. Verify it shows a green dot (connected)



> **Important:** After creating `mcp.json`, the server appears **disabled

> by default**. You must manually enable the toggle in Cursor Settings →

> MCP. Skipping this step causes agents to loop endlessly trying to find

> the server. If the server does not appear in the list, press

> `Ctrl+Shift+P` (or `Cmd+Shift+P` on macOS) → "Developer: Reload

> Window" first.



**Step 5 — Start your Flutter app** in debug mode:



```bash

flutter run

```



LogPilot writes the VM service URI automatically. The MCP server picks it up

and connects. Verify by asking your agent to call `get_snapshot`.



### Auto-Discovery



LogPilot writes the Dart VM WebSocket URI to

`.dart_tool/log_pilot_vm_service_uri` every time your app starts in debug

mode. The MCP server:



- Reads the file on startup

- Watches for changes (file system watcher)

- If the file doesn't exist yet (server started before app), waits for it

  to appear

- On hot restart: isolate recycles, extensions re-register, server detects

  the isolate event and re-resolves on the next tool call

- On full restart: URI changes, file updates, server detects the change and

  reconnects within the watch interval



**No manual URI copying is needed** in the normal workflow.



**If auto-discovery fails** (e.g., `.dart_tool` is not in the expected

location, or the app's working directory differs from the project root on

Windows), you have two fallback options:



1. **Pass the URI manually** — copy the `ws://...` URI from the Flutter

   debug console and add `--vm-service-uri=ws://127.0.0.1:PORT/TOKEN=/ws`

   to the `args` array in `mcp.json`.

2. **Pass the project root** — add

   `--project-root=` to the `args` array so the

   server knows where to find `.dart_tool/log_pilot_vm_service_uri`.



### What Agents Can Do



| Tool | What it does |

|------|--------------|

| `get_snapshot` | Structured summary: session ID, config, history counts, recent errors, active timers. Supports `group_by_tag` for per-tag breakdown. |

| `query_logs` | Filter by level, tag, limit. `deduplicate: true` collapses repeated entries while preserving different call sites. |

| `export_logs` | Full history as human-readable text or NDJSON. |

| `export_for_llm` | Compressed summary optimized for LLM context windows — prioritizes errors, deduplicates, truncates verbose entries. |

| `set_log_level` / `get_log_level` | Change or read verbosity at runtime. Crank to `verbose` for debugging, back to `warning` when done. |

| `clear_logs` | Wipe in-memory history. |

| `watch_logs` | Stream new entries as MCP push notifications. Filter by tag and level. |

| `stop_watch` | Stop the watcher and get a delivery summary. |



| Resource | Contents |

|----------|----------|

| `LogPilot://config` | Current LogPilotConfig as JSON |

| `LogPilot://session` | Session ID and active trace ID |

| `LogPilot://tail` | Latest batch from the active watcher (subscribable) |



### Agent Debugging Workflow



1. `get_snapshot` — see what's happening (errors, config, timers)

2. `set_log_level(level: "verbose")` — increase detail

3. *Reproduce the issue*

4. `query_logs(level: "error", deduplicate: true)` — find the root cause

5. `export_for_llm(token_budget: 2000)` — get compressed context for analysis

6. `set_log_level(level: "warning")` — restore quiet mode



### Claude Code / Terminal Usage



```bash

cd /log_pilot_mcp

dart run log_pilot_mcp --vm-service-uri=ws://127.0.0.1:PORT/TOKEN=/ws

```



Or use the `log_pilot_VM_SERVICE_URI` environment variable.



### Troubleshooting



| Problem | Solution |

|---------|----------|

| Server shows "Disabled" in Cursor Settings → MCP | Toggle the switch **ON** manually. New servers default to disabled. |

| Server not appearing in MCP settings | Reload the Cursor window after creating/editing `mcp.json`. |

| `Could not find package "log_pilot_mcp"` | `log_pilot_mcp` is not on pub — clone the [GitHub repo](https://github.com/MojtabaTavakkoli/log_pilot) and use the absolute path to `log_pilot_mcp/bin/log_pilot_mcp.dart`. |

| `Failed to connect to VM service` | App isn't running in debug mode, or the URI is stale. Start the app first. |

| Auto-discovery file not created | On Windows, the app's working directory may not match the project root. Pass `--project-root=` or use `--vm-service-uri` manually. |

| Tools fail after hot restart | Auto-recovers on the next call. If it persists, the VM port changed (full restart) — the URI file watcher handles this. |

| Server connects but tools return errors | The app must `import 'package:log_pilot/log_pilot.dart'` so the library is loaded. |



For the complete reference (manual URI, platform examples, `watch_logs`

parameters, `get_snapshot` parameters), see

[`log_pilot_mcp/README.md`](log_pilot_mcp/README.md).



---



## DevTools Extension



![DevTools Extension](screenshots/devtools_extension.png)



**Zero configuration** — add `log_pilot` as a dependency and a **LogPilot** tab

appears in Dart DevTools automatically.



- Real-time log table with color-coded level badges, tags, timestamps, and caller locations

- **Level filter** dropdown + **tag filter** dropdown + free-text search

- Auto-scroll with manual override

- **Toolbar**: Refresh, Clear, Set log level, Export (text/JSON), Snapshot

- **Detail view**: full message, metadata JSON tree, error + stack trace, error ID, breadcrumb timeline with copy-to-clipboard

- Works on all platforms including Flutter Web (uses VM service extensions, not expression evaluation)



| Filtered by Level + Tag | Detail with Metadata & Breadcrumbs |

|:-:|:-:|

| ![DevTools Table](screenshots/devtools_table.png) | ![DevTools Detail](screenshots/devtools_detail.png) |



---



## In-App Log Viewer



![In-App Log Viewer](screenshots/overlay_demo.gif)



```dart

MaterialApp(

  builder: (context, child) => LogPilotOverlay(child: child!),

  home: const MyHome(),

)

```



A **draggable, resizable bottom sheet** with full debug capabilities:



- Snap points at 25%, 50%, 75%, and full-screen

- **Level filter chips** (ALL, VERBOSE, DEBUG, INFO, WARNING, ERROR, FATAL)

- **Tag filter chips** — dynamically generated from logged records

- Text search across messages, tags, and levels

- **Record detail view** — tap any entry for full metadata, error, stack trace,

  breadcrumbs, caller, session/trace/error IDs, with copy-to-clipboard

- Auto-scroll toggle

- Copy full history as text or NDJSON

- Clear history button



Auto-hides in production. Override with `LogPilotOverlay(enabled: true)`.

Control FAB position: `LogPilotOverlay(entryButtonAlignment: Alignment.bottomLeft)`.



| Overlay List View | Record Detail View |

|:-:|:-:|

| ![Overlay List](screenshots/overlay_list.png) | ![Overlay Detail](screenshots/overlay_detail.png) |



---



## LLM Export



Compress log history to fit within an LLM's context window:



```dart

final summary = LogPilot.exportForLLM(tokenBudget: 2000);

```



The algorithm prioritizes errors, deduplicates consecutive identical

messages, truncates verbose entries, and fills remaining budget with the

most recent records. Default budget is 4000 tokens (~16k chars).



Also available via MCP: the `export_for_llm` tool accepts a `token_budget`

parameter and returns the compressed summary directly to the agent.



---



## Quick Start



### Install



```yaml

dependencies:

  log_pilot: ^0.15.3

```



### Pick Your Setup Level



**Full setup** — error zones + logging (recommended):



```dart

import 'package:flutter/material.dart';

import 'package:log_pilot/log_pilot.dart';



void main() {

  LogPilot.init(child: const MyApp());

}

```



`LogPilot.init()` replaces `runApp()` and auto-catches every Flutter error,

platform error, and uncaught zone exception.



**Config only** — you call `runApp()` yourself:



```dart

void main() {

  LogPilot.configure(config: LogPilotConfig(logLevel: LogLevel.info));

  runApp(const MyApp());

}

```



**Zero setup** — works immediately with sensible defaults:



```dart

LogPilot.info('Hello world'); // no init needed in debug mode

```



---



## Console Output



LogPilot wraps every log in a box-bordered block with level, timestamp,

clickable caller location, and your message:



![Console Output — Pretty Format](screenshots/console_pretty.png)



Three output modes are available:



| Mode | Use case | Example |

|------|----------|---------|

| `OutputFormat.pretty` | Human in IDE (default) | Box-bordered, colorized |

| `OutputFormat.plain` | AI agents / CI | `[INFO] [auth] User signed in \| {"userId": "123"}` |

| `OutputFormat.json` | Structured pipelines | `{"level":"INFO","timestamp":"...","message":"..."}` |



| Pretty | Plain | NDJSON |

|:-:|:-:|:-:|

| ![Pretty](screenshots/output_formats_pretty.png) | ![Plain](screenshots/output_formats_plain.png) | ![NDJSON](screenshots/output_formats_NDJSON.png) |



---



## Log Messages



Every method supports optional `error`, `stackTrace`, `metadata`, and `tag`:



```dart

LogPilot.verbose('Starting sync...');

LogPilot.debug('Cache key: user_42');

LogPilot.info('Order placed', metadata: {'orderId': 'ORD-456', 'total': 29.99});

LogPilot.warning('Retry attempt 3/5');

LogPilot.error('Checkout failed', error: e, stackTrace: st);

LogPilot.fatal('Database corrupted');

```



| Verbose | Info + Metadata |

|:-:|:-:|

| ![Verbose](screenshots/log_levels_verbose.png) | ![Info](screenshots/log_levels_info_metadata.png) |



| Error + Stack Trace + Breadcrumbs | Fatal |

|:-:|:-:|

| ![Error](screenshots/log_levels_error_stack_trace.png) | ![Fatal](screenshots/log_levels_fatal.png) |



---



## JSON Pretty-Printing



```dart

LogPilot.json('{"users": [{"id": 1, "name": "Alice"}]}');

```



Keys and values render in different colors. Customize with `jsonKeyColor`

and `jsonValueColor` in the config.



![JSON Highlighting](screenshots/json_highlight.png)



---



## Scoped Instance Loggers



Create a `LogPilotLogger` for class-level logging — every log is automatically

tagged:



```dart

class AuthService {

  static final _log = LogPilot.create('AuthService');



  Future signIn(String email) async {

    _log.info('Attempting sign in', metadata: {'email': email});

    try {

      await _auth.signIn(email);

      _log.info('Sign in successful');

    } catch (e, st) {

      _log.error('Sign in failed', error: e, stackTrace: st);

    }

  }

}

```



Scoped loggers also prefix timer labels: `_log.time('query')` produces `AuthService/query`.



---



## Network Logging



The **http** interceptor is built into the published package:



```dart

import 'package:log_pilot/log_pilot.dart';



final client = LogPilotHttpClient();

final response = await client.get(Uri.parse('https://api.example.com/users'));

```



![Network Logging](screenshots/network_logging.png)



Response log levels are set by HTTP status code: 5xx -> `error`, 4xx -> `warning`, 2xx/3xx -> `info`.



```dart

LogPilotHttpClient(

  logRequestHeaders: true,

  logRequestBody: true,

  logResponseHeaders: false,

  logResponseBody: true,        // opt-in (default: false)

  maxResponseBodySize: 4 * 1024, // truncate after 4 KB

  injectSessionHeader: true,     // adds X-LogPilot-Session / X-LogPilot-Trace

  createRecords: true,           // creates LogPilotRecord entries in history

)

```



Override level per status code:



```dart

LogPilotHttpClient(

  logLevelForStatus: (status) =>

      status == 429 ? LogLevel.error : LogPilotHttpClient.defaultLogLevelForStatus(status),

)

```



Query network errors from history:



```dart

final httpErrors = LogPilot.historyWhere(tag: 'http', hasError: true);

```



> **Dio, Chopper, GraphQL, and BLoC integrations** are available in the

> [source repo](https://github.com/MojtabaTavakkoli/log_pilot) but are **not

> included in the published package** yet. They will ship as separate

> packages in a future release. In the meantime you can copy the source file

> from the repo into your project.



---



## Log Sinks



Route log records to any destination alongside console output:



```dart

LogPilot.init(

  config: LogPilotConfig(

    sinks: [

      CallbackSink((record) {

        FirebaseCrashlytics.instance.log(record.message ?? '');

      }),

    ],

  ),

  child: const MyApp(),

);

```



Sinks fire **even when console output is off** (`enabled: false`), making

them ideal for production. Implement `LogSink` for custom sinks:



```dart

class RemoteSink implements LogSink {

  @override

  void onLog(LogPilotRecord record) {

    httpClient.post(apiUrl, body: record.toJsonString());

  }



  @override

  void dispose() {}

}

```



### Choosing the Right Sink



| Sink | Delivery | Best for |

|------|----------|----------|

| `CallbackSink` | Synchronous, per-record | Fire-and-forget: crash reporters, analytics |

| `AsyncLogSink` | Microtask-batched | Expensive I/O: HTTP uploads, file writes |

| `BufferedCallbackSink` | Timer + size-based batches | UI state — avoids `setState`-during-`build` |



```dart

// Microtask-batched

AsyncLogSink(flush: (records) {

  for (final r in records) { analyticsService.track(r.message ?? ''); }

})



// Timer + size-based

BufferedCallbackSink(

  maxBatchSize: 50,

  flushInterval: Duration(milliseconds: 500),

  onFlush: (batch) { setState(() => logRecords.addAll(batch)); },

)

```



Each sink's `onLog` is wrapped in a try-catch — a broken sink cannot silence the pipeline.



---



## File Logging



`FileSink` writes to local files with automatic rotation. **Mobile/desktop

only** (requires `dart:io`):



```dart

import 'dart:io';

import 'package:log_pilot/log_pilot.dart';

import 'package:log_pilot/log_pilot_io.dart';



LogPilot.init(

  config: LogPilotConfig(

    sinks: [

      FileSink(

        directory: Directory('/path/to/logs'),

        maxFileSize: 2 * 1024 * 1024,  // 2 MB per file

        maxFileCount: 5,

        format: FileLogFormat.text,     // or .json for NDJSON

        baseFileName: 'LogPilot',

      ),

    ],

  ),

  child: const MyApp(),

);



// Export all logs for bug reports:

final allLogs = await fileSink.readAll();

Share.share(allLogs);

```



---



## Config Presets



```dart

LogPilotConfig.debug()       // verbose, all details, colors on

LogPilotConfig.staging()     // info+, compact, 5s dedup window

LogPilotConfig.production(   // console off, warning+, sinks only

  sinks: [myCrashlyticsSink],

)

LogPilotConfig.web()         // info+, plain output, no caller capture, 5s dedup

```



| Factory | Log Level | Caller | Details | Dedup | Best for |

|---------|-----------|:------:|:-------:|-------|----------|

| `LogPilotConfig()` | verbose | Yes | Yes | off | Default |

| `.debug()` | verbose | Yes | Yes | off | IDE development |

| `.staging()` | info | Yes | No | 5s | QA builds |

| `.production()` | warning | No | No | 5s | Release (console off) |

| `.web()` | info | No | No | 5s | Flutter Web |



---



## Tagged Logging & Focus Mode



```dart

LogPilot.info('Starting payment', tag: 'checkout');



// Only show specific tags during development:

LogPilotConfig(onlyTags: {'checkout', 'auth'})

```



---



## Rate Limiting / Deduplication



Collapse identical messages within a time window:



```dart

LogPilotConfig(deduplicateWindow: Duration(seconds: 5))

```



When the same message + level repeats, only the first is printed. After

the window, a summary appears:



```

│ RenderFlex overflowed by 42.0 pixels

│ ... repeated 47 times

```



Deduplication applies to both console output and sink dispatch. The

in-memory history still receives every record.



---



## Log History / Ring Buffer



```dart

final records = LogPilot.history;

final errors  = LogPilot.historyWhere(level: LogLevel.error);

final text    = LogPilot.export();

final json    = LogPilot.export(format: ExportFormat.json);



LogPilot.clearHistory();

```



`historyWhere` supports rich filtering — all parameters combine with AND logic:



```dart

LogPilot.historyWhere(

  level: LogLevel.warning,

  tag: 'http',

  messageContains: 'timeout',

  traceId: 'req-abc',

  hasError: true,

  after: DateTime.now().subtract(const Duration(minutes: 5)),

  before: DateTime.now(),

  metadataKey: 'statusCode',

);

```



Configure the buffer size (default 500, set to 0 to disable):



```dart

LogPilotConfig(maxHistorySize: 1000)

```



---



## Session & Trace IDs



Every app launch gets a unique session UUID:



```dart

print(LogPilot.sessionId); // "a1b2c3d4-e5f6-4a7b-..."

```



For per-request correlation, use the scoped helper:



```dart

await LogPilot.withTraceId('req-12345', () async {

  await processPayment();   // all logs carry traceId 'req-12345'

  await sendReceipt();

});

// traceId is null here — even if processPayment threw

```



A synchronous variant is also available:



```dart

final total = LogPilot.withTraceIdSync('calc-1', () => computeTotal(cart));

```



Network interceptors automatically inject `X-LogPilot-Session` and

`X-LogPilot-Trace` headers.



---



## Navigation Logging



Auto-log every route transition:



```dart

MaterialApp(

  navigatorObservers: [LogPilotNavigatorObserver()],

)

```



Customize:



```dart

LogPilotNavigatorObserver(

  logLevel: LogLevel.info,

  tag: 'Nav',

  logArguments: false, // hide sensitive route arguments

)

```



---



## BLoC Observer



Log BLoC/Cubit lifecycle events:



```dart

import 'package:log_pilot/log_pilot_bloc.dart';



void main() {

  Bloc.observer = LogPilotBlocObserver();

  LogPilot.init(child: const MyApp());

}

```



Customize:



```dart

LogPilotBlocObserver(

  tag: 'state',

  logEvents: true,

  logTransitions: true,

  logCreations: false,

  transitionLevel: LogLevel.debug,

)

```



---



## Performance Timing



```dart

LogPilot.time('fetchUsers');

final users = await api.fetchUsers();

LogPilot.timeEnd('fetchUsers');  // logs: "fetchUsers: 342ms"

```



Exception-safe scoped timing:



```dart

final users = await LogPilot.withTimer('fetchUsers', work: () => api.getUsers());

final config = LogPilot.withTimerSync('parseConfig', work: () => parse(raw));

```



Multiple timers run concurrently. Scoped loggers prefix automatically:



```dart

final log = LogPilot.create('DB');

log.time('query');      // label: "DB/query"

log.timeEnd('query');   // logs: "DB/query: 12ms" with tag "DB"

```



`timeCancel` removes a timer without logging.



---



## Error Breadcrumbs



Automatic trail of events before each error:



```dart

LogPilot.info('User tapped checkout', tag: 'UI');

LogPilot.info('Cart validated', tag: 'Cart');

LogPilot.error('Payment failed', error: e, stackTrace: st);

// ↑ Breadcrumbs for the 2 prior events are attached

```



Manual breadcrumbs:



```dart

LogPilot.addBreadcrumb('Button tapped', category: 'ui');

LogPilot.addBreadcrumb('Theme changed', category: 'state', metadata: {'theme': 'dark'});

```



Configure: `LogPilotConfig(maxBreadcrumbs: 30)` (default 20, 0 to disable).



---



## Error IDs



Each error/fatal log receives a deterministic hash-based ID:



```dart

LogPilot.error('Network timeout', error: TimeoutException('connect'));

// Record includes: errorId: "lk-a1b2c3"

```



The same error signature always produces the same ID across sessions.

Numeric variations are normalized — "index 5 out of range 10" and

"index 3 out of range 8" produce the same ID.



---



## Sensitive Field Masking



```dart

LogPilotConfig(

  maskPatterns: [

    'password',              // substring — masks any key containing "password"

    '=accessToken',          // exact — masks only the key "accessToken"

    '~^(refresh|auth)_.*',   // regex — matches keys via RegExp

    'Authorization',

    'secret',

  ],

)

```



| Prefix | Match type | Example | Masks |

|--------|-----------|---------|-------|

| *(none)* | Substring | `'token'` | `accessToken`, `tokenExpiry`, `refresh_token` |

| `=` | Exact key | `'=accessToken'` | `accessToken` only |

| `~` | Regex | `'~^api_key$'` | `api_key` only |



Recursive masking applies to both headers and nested JSON bodies.



---



## Error Silencing



Suppress known, noisy errors from console — crash reporters still receive them:



```dart

LogPilotConfig(silencedErrors: {'RenderFlex overflowed', 'HTTP 404'})

```



---



## Runtime Log-Level Override



Change verbosity without code edits or restart:



```dart

LogPilot.setLogLevel(LogLevel.verbose); // crank up for debugging

// ... reproduce the issue ...

LogPilot.setLogLevel(LogLevel.warning); // quiet down

```



---



## Lazy Message Evaluation



```dart

LogPilot.debug(() => 'Cache: ${cache.entries.map((e) => e.key).join(", ")}');

```



The closure is only called if debug level is active.



---



## Instrumentation Helpers



Wrap any expression with automatic timing, result logging, and error capture:



```dart

final config = LogPilot.instrument('parseConfig', () => parseConfig(raw));

final users = await LogPilot.instrumentAsync('fetchUsers', () => api.getUsers());

```



On success: logs at `debug` level with return value and elapsed time.

On failure: logs at `error` level with exception and stack trace, then rethrows.



---



## Self-Diagnostics



Monitor LogPilot's own performance and automatically degrade verbosity

when throughput spikes:



```dart

LogPilot.enableDiagnostics(

  autoDegrade: true,

  throughputThreshold: 50, // records per second before degrading

);



final snap = LogPilot.diagnostics?.snapshot;

// LogPilotDiagnosticsSnapshot(records: 142, avgSinkLatency: 34us, ...)



LogPilot.disableDiagnostics();

```



When throughput exceeds the threshold, the log level is automatically

raised to `warning`. When throughput drops below half the threshold,

the original level is restored.



---



## Crash Reporter Integration



```dart

LogPilot.init(

  onError: (error, stack) {

    FirebaseCrashlytics.instance.recordError(error, stack);

  },

  child: const MyApp(),

);

```



---



## Diagnostic Snapshot



One-call structured summary of recent LogPilot activity:



```dart

final snap = LogPilot.snapshot();

// Returns Map with: sessionId, traceId, config, history counts,

// recentErrors (last 5), recentLogs (last 10), activeTimers



final jsonStr = LogPilot.snapshotAsJson();

```



Group recent logs by tag:



```dart

final snap = LogPilot.snapshot(groupByTag: true, perTagLimit: 3);

// snap['recentByTag']['Auth'] -> {total: 15, recent: [...last 3...]}

```



---



## Web Platform



The core `package:log_pilot/log_pilot.dart` is fully web-compatible — zero `dart:io`

dependency. All features work on Flutter Web:



- Console output, log history, navigation observer, BLoC observer, timing

- In-app log viewer overlay

- Network logging with `LogPilotHttpClient`

- DevTools extension



File logging requires `dart:io` — import `package:log_pilot/log_pilot_io.dart`

for mobile/desktop only. Use `LogPilotConfig.web()` for optimized web defaults.



---



## Testing



```dart

tearDown(() {

  LogPilot.reset(); // clears config, history, timers, and trace IDs

});

```



---



## Configuration Reference



| Option | Type | Default | Description |

|--------|------|---------|-------------|

| `enabled` | `bool` | `kDebugMode` | Master switch. Off in release. |

| `logLevel` | `LogLevel` | `verbose` | Minimum severity to print. |

| `outputFormat` | `OutputFormat` | `pretty` | `pretty` / `plain` / `json` |

| `showTimestamp` | `bool` | `true` | Show HH:mm:ss.SSS |

| `showCaller` | `bool` | `true` | Clickable source location |

| `showDetails` | `bool` | `true` | Error body, stack traces |

| `colorize` | `bool` | `true` | ANSI colors |

| `maxLineWidth` | `int` | `100` | Box width in characters |

| `stackTraceDepth` | `int` | `8` | Max stack frames shown |

| `maxPayloadSize` | `int` | `10240` | Truncate payloads (bytes) |

| `maskPatterns` | `List` | `['Authorization', 'password', 'token', 'secret']` | Fields to mask (`=exact`, `~regex`, or substring) |

| `jsonKeyColor` | `AnsiColor` | `cyan` | JSON key color |

| `jsonValueColor` | `AnsiColor` | `green` | JSON value color |

| `silencedErrors` | `Set` | `{}` | Suppress matching errors |

| `onlyTags` | `Set` | `{}` | Only print matching tags |

| `sinks` | `List` | `[]` | Additional output destinations |

| `deduplicateWindow` | `Duration` | `Duration.zero` | Collapse identical messages (console + sinks) |

| `maxHistorySize` | `int` | `500` | Ring buffer size (0 = off) |

| `maxBreadcrumbs` | `int` | `20` | Breadcrumb buffer (0 = off) |



---



## Package Imports



| Import | What you get | Web safe? | Published? |

|--------|--------------|:---------:|:----------:|

| `package:log_pilot/log_pilot.dart` | Core: `LogPilot`, `LogPilotLogger`, `LogPilotConfig`, `LogPilotRecord`, `LogLevel`, `LogSink`, `CallbackSink`, `AsyncLogSink`, `BufferedCallbackSink`, `LogHistory`, `ExportFormat`, `LogPilotNavigatorObserver`, `LogPilotOverlay`, `LogPilotHttpClient`, ANSI helpers | Yes | Yes |

| `package:log_pilot/log_pilot_io.dart` | `FileSink`, `FileLogFormat` (requires `dart:io`) | No | Yes |

| `package:log_pilot/log_pilot_dio.dart` | `LogPilotDioInterceptor` (add `dio` to pubspec) | Yes | Repo only* |

| `package:log_pilot/log_pilot_chopper.dart` | `LogPilotChopperInterceptor` (add `chopper`) | Yes | Repo only* |

| `package:log_pilot/log_pilot_graphql.dart` | `LogPilotGraphQLLink` (add `gql`, `gql_exec`, `gql_link`) | Yes | Repo only* |

| `package:log_pilot/log_pilot_bloc.dart` | `LogPilotBlocObserver` (add `bloc`) | Yes | Repo only* |



> \* These barrels are in the source repo but excluded from the published

> package. They will ship as separate packages (e.g. `log_pilot_dio`) in a

> future release.



---



## Example App



A full runnable example with tappable buttons for every feature lives in

[`example/`](example/):



```bash

cd example && flutter run

```



![Example App](screenshots/example_app.png)



---



## Features at a Glance



| Feature | What it does |

|---------|--------------|

| **MCP server** | AI agents query, filter, watch, and control live logs via MCP protocol |

| **DevTools extension** | Real-time log viewer tab inside Dart DevTools — zero config |

| **In-app log viewer** | `LogPilotOverlay` debug sheet with filters, search, and live updates |

| **LLM export** | Compress log history for AI context windows |

| **One-line setup** | Replace `runApp()` with `LogPilot.init()` — every error is auto-formatted |

| **Pretty Flutter errors** | 15+ contextual hints, simplified stacks, clickable source locations |

| **Level-based logging** | `verbose` / `debug` / `info` / `warning` / `error` / `fatal` with structured metadata and tags |

| **Scoped loggers** | `LogPilot.create('AuthService')` for class-level auto-tagging |

| **Log sinks** | Route records to files, Crashlytics, Sentry, or any backend |

| **Built-in file logging** | `FileSink` with automatic rotation by size, text or JSON format |

| **Lazy messages** | `LogPilot.debug(() => expensiveString())` — skips work when filtered |

| **Network interceptors** | http (published); Dio, Chopper, GraphQL (repo / future packages) |

| **JSON highlighting** | Auto-detect and colorize keys/values |

| **Sensitive field masking** | Recursive masking in headers and JSON bodies |

| **Config presets** | `LogPilotConfig.debug()`, `.staging()`, `.production()`, `.web()` |

| **Rate limiting / dedup** | Collapse identical messages within a time window |

| **Log history** | In-memory ring buffer — filter, export, attach to bug reports |

| **Output formats** | `pretty`, `plain`, `json` — human and machine modes |

| **Diagnostic snapshot** | `LogPilot.snapshot()` — one-call summary for bug reports |

| **Error breadcrumbs** | Automatic trail of events before each error |

| **Error IDs** | Deterministic `lk-XXXXXX` hash for cross-session tracking |

| **Runtime log-level override** | Change verbosity at runtime without restart |

| **Instrumentation helpers** | One-line timing + error capture for any expression |

| **Session & trace IDs** | Auto-generated session UUID + per-request trace IDs |

| **Navigation logging** | Auto-logs push/pop/replace with route names & arguments |

| **BLoC observer** | Logs create/close, events, state changes, and errors |

| **Performance timing** | `LogPilot.time` / `LogPilot.timeEnd` — like `console.time` |

| **Web compatible** | Core barrel is `dart:io`-free — works on Flutter Web |

| **Lightweight core** | Optional deps (Dio, Chopper, GraphQL, BLoC) — add only what you use |



---



## Contributing



Contributions are welcome. See [CONTRIBUTING.md](CONTRIBUTING.md) for

architecture details and development setup.



## License



MIT — see [LICENSE](LICENSE).