AndroJack MCP

AndroJack — The Jack of All Android Trades

*An MCP server that equips your AI coding assistant with live, verified Android knowledge — so it builds from official sources, not from memory.*

Also works with: Windsurf · VS Code Copilot · Google Antigravity · JetBrains AI — see Manual Config below ↓

VS Code distribution: Also live on the VS Code Marketplace as AndroJack MCP for VS Code.

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Table of Contents

• The Crisis That Created This Tool
• What Actually Breaks In Practice
• What AndroJack Does
• Honest Activation Model
• What Can Still Break — Even at Level 3
• Defence-in-Depth
• The Killer Argument
• The 23 Tools
• Quick Start
• Manual Config
• Ecosystem: Google's First-Party Tools
• Security & Privacy
• Changelog

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🔥 The Crisis That Created This Tool

In 2025, the Stack Overflow Developer Survey asked 49,000 developers about their experience with AI coding tools. The results should alarm every Android engineer:

• 84% of developers now use AI coding tools — up from 76% the year before.
• Trust in AI accuracy collapsed from 40% to just 29% in a single year.
• 35% of all Stack Overflow visits in 2025 are now triggered by developers debugging and fixing AI-generated code.

The gap between usage and trust is not a coincidence. It is the product of a structural problem: AI models predict tokens, not APIs. They were trained on a snapshot of the world and have no mechanism to know what changed at API 30, what shipped at Google I/O 2025, or what Google Play now rejects at review time.

For Android developers, this failure mode is uniquely dangerous. Android has the fastest-moving ecosystem in mobile development — a new Compose BOM every month, Navigation 3 going stable after seven years of Nav2, Android 16 rewriting the rules on screen orientation locking — and most AI tools have training data that is six months to two years stale by the time you use them.

The result is not just bad code. It is confidently bad code.

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⚡ What Actually Breaks In Practice — Documented Evidence

These are not hypothetical risks. They are documented failure modes from real developer projects.

The Navigation 3 Hallucination (January 2026)

A published case study from Atomic Robot documented a live Navigation 2 → Navigation 3 migration using both Gemini and Claude — with internet access enabled on both. The conclusion, verbatim:

*"LLMs still hallucinate versions. Even with internet access, both agents wanted to use an outdated release candidate instead of the stable 1.0.0 release."*

Navigation 3 went stable in November 2025 after seven years of the same library. It is a complete architectural rethink: back stacks are now plain Kotlin lists, the monolithic nav graph is gone, and NavDisplay replaces NavController. Google's own migration guide is so aware that AI tools get this wrong that it now contains special "AI Agent:" annotations — instructions embedded directly in the official docs for AI tools to follow. An AI tool that generates Nav2 code for a new Compose project in 2026 is not making a small mistake. It is creating an architectural incoherence that requires a full rewrite to fix.

The Compose Deprecation Treadmill

Jetpack Compose ships a new BOM every month. Since most models' training cutoffs, these APIs changed:

Every one of these compiles. Most run without errors. The bugs surface later in CI flakiness, UI regressions, or Play Store review failures.

The Android 16 / API 36 Mandate (in force since August 31, 2026)

Android 16 made a platform-level change affecting every published app: on devices ≥600dp — tablets, foldables, ChromeOS — apps can no longer lock screen orientation or restrict resizability. Since August 31, 2026, Google Play requires new apps and updates to target API 36 (extension available to November 1, 2026). Android 17 / API 37 removes the remaining opt-out.

An AI tool generating android:screenOrientation="portrait" or android:resizeableActivity="false" today is generating code that triggers App Compatibility warnings in Play Console, fails large-screen quality checks, and gets apps demoted in Play Store search results.

The business impact is not theoretical: Foldable users spend 14× more on apps than phone-only users. Tablet + phone users spend 9× more. FlipaClip saw 54% growth in tablet users within four months of going adaptive.

The KMP Silent Failure

Kotlin Multiplatform went mainstream in 2025 — over 900 new KMP libraries published, Room added KMP support, companies now hire specifically for KMP skills. When a developer on a KMP project asks an AI tool to add database support, the AI generates Android-only Room code. It compiles. It runs perfectly on Android. The iOS build fails. The developer spends hours debugging before realizing the root cause: their AI tool does not know KMP exists.

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🧩 What AndroJack Does

AndroJack is a documentation-grounded Android engineering MCP server. It gives your AI coding assistant 23 specialized tools that fetch live, verified answers from official Android and Kotlin sources — instead of predicting from stale training data.

It does not make the AI smarter. It makes the AI accountable to evidence.

Think of it as a pre-build linter for LLMs. While other tools retrieve documentation, AndroJack acts as a strict architectural gatekeeper.

Without AndroJack:  You ask → AI predicts from stale weights → Code (possibly wrong)

With AndroJack: You ask → AI calls tool → Tool fetches official source live → AI reads verified answer → Code (grounded)

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⚠️ Honest Activation Model — Two Levels

[!IMPORTANT]

This is the most important thing to understand before you install AndroJack.

Level 1 is passive. The tools are available but the AI decides when to use them. An AI building a Compose screen may call architecture_reference but skip material3_expressive — and ship M3E violations silently.

Level 2 is active. The androjack_grounding_gate system prompt maps every task type to the correct tool. Building Compose UI? The AI is mandated to call material3_expressive first. Adding a dependency? It must call gradle_dependency_checker. No exceptions.

Level 3 is the loop-back. android_code_validator runs on every code block the AI generates before returning it to the user. 34 rules covering removed APIs, deprecated patterns, Android 16/17 compliance, and Compose-First migration signals. Comments are ignored, so a migration note like // replaced AsyncTask never triggers a false FAIL. Results come back as text and as structuredContent with an output schema. Verdict FAIL means the AI must fix and re-validate — the user never sees the broken code.

→ *For full grounding, always activate Level 2 + Level 3. See Getting the Full Guarantee below.*

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🪲 What Can Still Break — Even at Level 3

[!IMPORTANT]

AndroJack is a documentation-grounding and API-validation tool. It is not a Compose layout engine, a design system enforcer, or a runtime renderer. Level 3 catches removed APIs and deprecated patterns. It cannot catch every class of Android bug. This is not a limitation of AndroJack — it is a fundamental property of static text analysis applied to a visual, runtime-rendered UI framework.

The following bugs were encountered in a real Android app built with AndroJack at Level 2 (v1.4.0). They are documented here honestly so you know exactly what to watch for — and where to reach for different tools.

✅ What Level 3 Catches