Building CLI Applications on Amplifier

Amplifier is Microsoft's composable AI agent framework that enables:

• Bundle composition - Mix session orchestrators, hooks, tools, and providers
• Module ecosystem - 36+ modules available (Module Catalog)
• Provider flexibility - Claude, GPT, Gemini, local models, and more
• Production-ready - Logging, observability, and hooks built-in

This skill teaches how to build CLI applications using amplifier-foundation patterns - the source of truth for Amplifier application development.

Amplifier Ecosystem

This skill is part of the broader Amplifier ecosystem:

Core Repositories

• amplifier - Main framework repository
• amplifier-core - Core library (execution engine)
• amplifier-foundation - Foundation library (configuration/composition layer)
• Amplifier Modules - Module catalog (36+ available modules)

Reference Implementations

• amplifier-simplecli - Production terminal UI implementation

Reference Implementation

See amplifier-simplecli for a complete working example demonstrating these patterns in production. This terminal UI implementation showcases:

• Full bundle composition workflow
• Memory system integration (tool-memory, hooks-memory-capture, context-memory)
• 14 pre-configured modules
• Streaming UI with hooks-event-broadcast
• Complete documentation structure

Key Resources:

• 📊 ARCHITECTURE_FLOWS.md - Visual diagrams showing Foundation (setup) → Core (runtime) separation
• 🗺️ ROADMAP.md - Feature roadmap with implementation details
• 🔧 MODULE_GAP_ANALYSIS.md - Module coverage and requirements

Use it as a reference when building your own CLI applications.

Core Workflow

Every Amplifier application follows this fundamental pattern:

from amplifier_foundation import load_bundle

async def main():
    # 1. Load bundles
    foundation = await load_bundle("git+https://github.com/microsoft/amplifier-foundation@main")
    provider = await load_bundle("./providers/anthropic.yaml")  # Your provider config

    # 2. Compose bundles (later overrides earlier)
    composed = foundation.compose(provider)

    # 3. Prepare (resolves and downloads modules)
    prepared = await composed.prepare()

    # 4. Create session and execute
    async with await prepared.create_session() as session:
        response = await session.execute("Hello!")
        print(response)

This is the pattern. Everything else builds on this foundation.

Quick Start

# Install amplifier-foundation
pip install amplifier-foundation

# Or with uv
uv add amplifier-foundation

Example Bundles

Complete, production-ready bundle examples are available in references/EXAMPLES.md:

• Base Bundle - Session orchestrator, memory system, hooks, and tools
• Provider Configurations - Claude Opus 4.5, Sonnet 4.5, Haiku 4
• Agent Bundle - Specialized bug-hunter agent example

These examples show real bundle structures you can copy and adapt. In your CLI app, organize them as:

your-cli/
├── bundles/base.md
├── providers/opus.yaml
└── agents/bug-hunter.md

What is a Bundle?

A Bundle is a composable configuration unit that produces a mount plan for sessions.

Bundle → compose() → prepare() → create_session() → execute()

Bundle Sections

bundle

session

providers

tools

hooks

agents

context

instruction

Bundle Format

Bundles are markdown files with YAML frontmatter:

---
bundle:
  name: my-app
  version: 1.0.0

session:
  orchestrator: {module: loop-streaming}
  context: {module: context-simple}

providers:
  - module: provider-anthropic
    source: git+https://github.com/microsoft/amplifier-module-provider-anthropic@main
    config:
      default_model: claude-sonnet-4-5

tools:
  - module: tool-filesystem
    source: git+https://github.com/microsoft/amplifier-module-tool-filesystem@main
---

You are a helpful assistant for software development.

Composition Pattern

Bundles compose with later overriding earlier:

result = base.compose(overlay)  # overlay wins on conflicts

Merge Rules

session

providers

tools

hooks

instruction

Common Composition Patterns

Base + Environment:

import os

base = await load_bundle("./bundles/base.md")
dev_overlay = await load_bundle("./bundles/dev.md")
prod_overlay = await load_bundle("./bundles/prod.md")

env = os.getenv("ENV", "dev")
overlay = dev_overlay if env == "dev" else prod_overlay
bundle = base.compose(overlay)

Feature Bundles:

filesystem = Bundle(name="fs", tools=[{"module": "tool-filesystem", "source": "..."}])
web = Bundle(name="web", tools=[{"module": "tool-web", "source": "..."}])

# Compose what you need
full = base.compose(filesystem).compose(web)

Includes Chain (Declarative):

# dev.md
bundle:
  name: dev
includes:
  - ./base.md
providers:
  - module: provider-anthropic
    config: {debug: true}

CLI Application Architecture

Use this blueprint for building CLI applications:

import asyncio
import logging
from dataclasses import dataclass
from pathlib import Path

from amplifier_foundation import Bundle, load_bundle


@dataclass
class AppConfig:
    """Application configuration."""
    provider_bundle: str = "anthropic-sonnet.yaml"
    api_key: str | None = None
    log_level: str = "INFO"

    @classmethod
    def from_env(cls) -> "AppConfig":
        return cls(
            provider_bundle=os.getenv("PROVIDER", "anthropic-sonnet.yaml"),
            api_key=os.getenv("ANTHROPIC_API_KEY"),
            log_level=os.getenv("LOG_LEVEL", "INFO"),
        )

    def validate(self) -> None:
        if not self.api_key:
            raise ValueError("ANTHROPIC_API_KEY not set")


class AmplifierApp:
    """Amplifier CLI application pattern."""

    def __init__(self, config: AppConfig):
        self.config = config
        self.session = None
        self.logger = logging.getLogger("amplifier_app")

    async def initialize(self) -> None:
        """Initialize: load bundles, compose, prepare, create session."""
        # Load foundation
        foundation = await load_bundle("git+https://github.com/microsoft/amplifier-foundation@main")

        # Load provider
        provider = await load_bundle(f"./providers/{self.config.provider_bundle}")

        # Add tools
        tools = Bundle(
            name="app-tools",
            tools=[
                {"module": "tool-filesystem", "source": "git+..."},
                {"module": "tool-bash", "source": "git+..."},
            ],
        )

        # Compose all bundles
        composed = foundation.compose(provider).compose(tools)

        # Prepare (downloads modules)
        prepared = await composed.prepare()

        # Create session
        self.session = await prepared.create_session()

    async def execute(self, prompt: str) -> str:
        """Execute a prompt."""
        if not self.session:
            raise RuntimeError("Session not initialized")
        return await self.session.execute(prompt)

    async def shutdown(self) -> None:
        """Graceful shutdown."""
        if self.session:
            await self.session.cleanup()

    async def __aenter__(self):
        await self.initialize()
        return self

    async def __aexit__(self, *args):
        await self.shutdown()


async def main():
    config = AppConfig.from_env()
    config.validate()

    async with AmplifierApp(config) as app:
        response = await app.execute("Hello!")
        print(response)


if __name__ == "__main__":
    asyncio.run(main())

Key Architectural Principles

1. Configuration as Dataclass: Use

   @dataclass

   for config, load from env/files
2. Initialize/Execute/Shutdown Lifecycle: Clean lifecycle management
3. Context Manager Pattern: Use

   async with

   for automatic cleanup
4. Composition Over Inheritance: Compose bundles, don't subclass

Session Patterns

Basic Session

bundle = await load_bundle("/path/to/bundle.md")
prepared = await bundle.prepare()

async with await prepared.create_session() as session:
    response = await session.execute("Hello!")

Multi-Turn Conversation

Session maintains context automatically:

async with await prepared.create_session() as session:
    await session.execute("My name is Alice")
    response = await session.execute("What's my name?")
    # Response knows about Alice

Resuming Sessions

# First session
async with await prepared.create_session() as session:
    await session.execute("Remember: X=42")
    session_id = session.session_id

# Later: resume
async with await prepared.create_session(session_id=session_id) as session:
    response = await session.execute("What is X?")
    # Knows X=42

Agent Delegation

Defining Agents

Example agent bundle structure (see references/EXAMPLES.md for complete example):

---
bundle:
  name: bug-hunter
  version: 1.0.0
  description: Finds and fixes bugs

providers:
  - module: provider-anthropic
    config:
      default_model: claude-sonnet-4-5
      temperature: 0.3
---

You are an expert bug hunter. Find bugs systematically.

Spawning Agents

# Load agent as bundle
agent_bundle = await load_bundle("./agents/bug-hunter.md")

# Spawn sub-session
result = await prepared.spawn(
    child_bundle=agent_bundle,
    instruction="Find the bug in auth.py",
    compose=True,            # Compose with parent bundle
    parent_session=session,  # Inherit UX from parent
)

print(result["output"])

@Mention System

Reference context files using

@namespace:path

See @foundation:context/guidelines.md for guidelines.

How it works:

1. During composition, each bundle's

   base_path

   is tracked by namespace
2. PreparedBundle resolves

   @namespace:path

   references
3. Content is loaded and included inline

Memory System (Custom Extension)

⚠️ Note: The memory system is a custom community extension, NOT part of official amplifier-foundation.

Amplifier can be extended with persistent memory capabilities using three custom modules:

What Memory Enables

• Persistent observations across sessions (bugfix, feature, discovery, decision)
• Session tracking with structured summaries and next_steps
• Automatic learning capture from tool outputs (no manual add_memory calls)
• Full-text search across all memory content
• Progressive disclosure for cost-effective context injection

Quick Setup

Add to your bundle:

session:
  memory_context:
    module: context-memory
    source: git+https://github.com/michaeljabbour/amplifier-module-context-memory@main

hooks:
  - module: hooks-memory-capture
    source: git+https://github.com/michaeljabbour/amplifier-module-hooks-memory-capture@main
    config:
      min_content_length: 50
      auto_summarize_interval: 10

tools:
  - module: tool-memory
    source: git+https://github.com/michaeljabbour/amplifier-module-tool-memory@main
    config:
      storage_path: ~/.amplifier/memories.db
      max_memories: 1000
      enable_fts: true
      enable_sessions: true

For complete setup, configuration options, and usage patterns, see references/MEMORY.md.

Philosophy

Mechanism, Not Policy

Foundation provides mechanism for bundle composition. It doesn't decide which bundles to use - those are policy decisions for your application.

Foundation (mechanism):          App (policy):
- load_bundle()                  - Search path order
- compose()                      - Well-known bundles
- prepare()                      - @user:, @project: shortcuts
- create_session()               - Environment-specific config

Text-First

• Bundles are markdown (human-readable)
• Configuration is YAML (diffable)
• No binary formats

Composable

Small bundles compose into larger configurations. Prefer composition over complexity.

Deep Dive References

For detailed information on specific topics, see the

references/

Architecture & Core Concepts

• ARCHITECTURE.md - Foundation architecture patterns and philosophy
• HOOKS.md - Complete hooks system documentation

Building Applications

• BUILD_PATTERNS.md - Comprehensive CLI build patterns and implementation details

Extensions & Customization

• MEMORY.md - Custom memory system extension guide (community contribution)
• CUSTOM_EXTENSIONS.md - Information about community extensions

Project Resources

• CONTRIBUTING.md - Repository structure and contribution guidelines
• TROUBLESHOOTING.md - Production patterns, bug fixes, and troubleshooting guide
• REFERENCE_IMPLEMENTATION_HISTORY.md - Evolution of amplifier-simplecli reference implementation

These references provide comprehensive coverage beyond the quick start patterns in this document. Start here for overview, explore references for depth.

Reference: amplifier-app-cli

The

amplifier-app-cli

When building your own CLI, start from the foundation patterns above, not from copying amplifier-app-cli internals.

Production Configuration Choices

When building production CLIs, leverage amplifier-foundation's native capabilities. The example bundles in references/EXAMPLES.md demonstrate production-ready choices.

Orchestrator: loop-streaming

Why loop-streaming over loop-events:

session:
  orchestrator:
    module: loop-streaming
    config:
      extended_thinking: true
      max_iterations: 25

Key benefits:

• Parallel tool execution via

  asyncio.gather()

  prevents race conditions
• Tool results are guaranteed complete before being added to context
• Streaming support for better user experience
• Production-tested in amplifier-app-cli

Foundation provides:

• loop-basic

  - Sequential execution (simple, deterministic)

• loop-events

  - Event-driven with hooks (vulnerable to race conditions)

• loop-streaming

  - Parallel execution with determinism (production choice)

Context Manager: context-simple

Why context-simple over context-persistent:

session:
  context:
    module: context-simple
    config:
      max_tokens: 200000
      compact_threshold: 0.8
      auto_compact: true

Key benefits:

• In-memory context management (fast startup)
• Automatic compaction when approaching token limits
• Same compaction logic as context-persistent
• Perfect for stateless CLI sessions

Foundation provides:

• context-simple

  - In-memory with auto-compaction (CLI default)

• context-persistent

  - File-based memory loading (for long-term memory)

• context-memory

  - Advanced memory patterns

When to use persistent: If your CLI needs to load previous conversation history at startup (rare for CLI tools).

Safety Hooks from Foundation Ecosystem

The example bundle includes production safety hooks from amplifier-foundation:

hooks:
  # Approval for dangerous operations
  - module: hooks-approval
    source: git+https://github.com/microsoft/amplifier-module-hooks-approval@main
    config:
      auto_approve: false
      dangerous_patterns: ["rm -rf", "sudo", "DROP TABLE", ...]

  # Automatic file backups
  - module: hooks-backup
    source: git+https://github.com/microsoft/amplifier-module-hooks-backup@main

  # Git and datetime awareness
  - module: hooks-status-context
    source: git+https://github.com/microsoft/amplifier-module-hooks-status-context@main
    config:
      include_datetime: true
      include_git_status: true

Note: Cost tracking hooks are not currently available in amplifier-foundation. Monitor token usage through the hooks-streaming-ui module's token display feature.

Validation: amplifier-app-cli uses the same foundation modules, proving production viability.

Common Development Tasks

Adding a New Provider

1. Create

   providers/my-provider.yaml

   :

   bundle:
     name: my-provider
   providers:
     - module: provider-openai
       source: git+https://github.com/microsoft/amplifier-module-provider-openai@main
       config:
         default_model: gpt-4o
   

2. Load and compose:

   provider = await load_bundle("./providers/my-provider.yaml")
   composed = foundation.compose(provider)
   

Adding Tools

Compose a tools bundle:

tools = Bundle(
    name="my-tools",
    tools=[
        {"module": "tool-filesystem", "source": "git+..."},
        {"module": "tool-bash", "source": "git+...", "config": {"allowed_commands": ["ls", "cat"]}},
    ],
)
composed = base.compose(tools)

Testing with Mock Provider

test_bundle = Bundle(
    name="test",
    providers=[{
        "module": "provider-mock",
        "source": "git+https://github.com/microsoft/amplifier-module-provider-mock@main",
        "config": {"responses": ["Hello!", "How can I help?"]},
    }],
)

Validation

from amplifier_foundation import load_bundle

bundle = await load_bundle(path)
prepared = await bundle.prepare()  # Activates modules (may download/install)

Error Handling

from amplifier_foundation import (
    load_bundle,
    BundleNotFoundError,
    BundleLoadError,
    BundleValidationError,
)

try:
    bundle = await load_bundle(path)
except BundleNotFoundError:
    print(f"Bundle not found: {path}")
except BundleLoadError as e:
    print(f"Failed to load: {e}")
except BundleValidationError as e:
    print(f"Invalid bundle: {e}")

Building a Complete CLI Application

Detailed guide available: For comprehensive build patterns, implementation details, and best practices, see references/BUILD_PATTERNS.md.

This section demonstrates how to build a full-featured CLI using foundation patterns. Following these patterns results in significantly less code (~85% reduction) compared to implementing session management, bundle loading, and configuration merging yourself.

Example Architecture

your-cli/
├── your_cli/
│   ├── app.py                  Core app class encapsulating foundation workflow
│   ├── config.py               Configuration dataclass
│   ├── session_manager.py      Session metadata storage (not state!)
│   ├── project.py              Project detection logic
│   ├── main.py                 CLI entry point (Typer/Click/argparse)
│   └── commands/               Command implementations
├── providers/                   Provider bundles
├── bundles/                     Base bundles
└── agents/                      Agent bundles

Core Pattern: AmplifierApp Class

The

AmplifierApp

class AmplifierApp:
    """Foundation-based CLI application."""

    def __init__(self, config: Config):
        self.config = config
        self.session: Optional[Session] = None
        self.prepared: Optional[PreparedBundle] = None

    async def initialize(self) -> None:
        """Initialize: load → compose → prepare → session."""
        bundles = []

        # 1. Load foundation
        foundation = await load_bundle(
            "git+https://github.com/microsoft/amplifier-foundation@main"
        )
        bundles.append(foundation)

        # 2. Load provider
        provider = await load_bundle(self.config.provider)
        bundles.append(provider)

        # 3. Load config files (configs ARE bundles!)
        global_config = Path.home() / ".amplifier" / "config.yaml"
        if global_config.exists():
            bundles.append(await load_bundle(str(global_config)))

        # 4. Load project config
        if self.config.project_root:
            project_config = find_project_config(self.config.project_root)
            if project_config:
                bundles.append(await load_bundle(str(project_config)))

        # 5. Compose all (later wins)
        composed = bundles[0]
        for bundle in bundles[1:]:
            composed = composed.compose(bundle)

        # 6. Prepare and create session
        self.prepared = await composed.prepare()
        self.session = await self.prepared.create_session()

    async def execute(self, prompt: str) -> str:
        """Execute prompt against session."""
        return await self.session.execute(prompt)

    async def spawn_agent(self, agent_path: str, instruction: str) -> dict:
        """Spawn agent sub-session."""
        agent_bundle = await load_bundle(agent_path)
        return await self.prepared.spawn(
            child_bundle=agent_bundle,
            instruction=instruction,
            compose=True,
            parent_session=self.session,
        )

Key Insights:

• Direct foundation API usage (no wrappers)
• Config files ARE bundles (reuse mechanism)
• Composition handles all merging
• Foundation manages session state
• App layer just orchestrates composition order

Configuration System

Simple dataclass with environment variable support:

@dataclass
class Config:
    """Application configuration."""

    provider: str = field(
        default_factory=lambda: os.getenv(
            "AMPLIFIER_PROVIDER",
            "./providers/anthropic.yaml"
        )
    )
    bundle: Optional[str] = field(
        default_factory=lambda: os.getenv("AMPLIFIER_BUNDLE")
    )
    bundles: list[str] = field(default_factory=list)
    project_root: Optional[Path] = None

    @classmethod
    def from_env_and_project(cls) -> "Config":
        """Load from env + project detection."""
        config = cls()
        manager = ProjectManager()
        config.project_root = manager.get_project_root()
        return config

No custom config merging needed - bundle composition handles it!

Project Detection

Lightweight project management (~50 lines vs app-cli's complex multi-project system):

class ProjectManager:
    def get_project_root(self) -> Path:
        """Find project root (.git or .amplifier directory)."""
        cwd = Path.cwd()
        for parent in [cwd, *cwd.parents]:
            if (parent / ".git").exists() or (parent / ".amplifier").exists():
                return parent
            if parent == Path.home():
                return cwd
        return cwd

    def get_project_id(self, project_root: Path) -> str:
        """Generate stable project ID from path."""
        return hashlib.md5(str(project_root.resolve()).encode()).hexdigest()[:8]

    def get_project_storage(self, project_root: Path) -> Path:
        """Get project-specific storage directory."""
        project_id = self.get_project_id(project_root)
        storage = Path.home() / ".amplifier" / "projects" / project_id
        storage.mkdir(parents=True, exist_ok=True)
        return storage

Session Metadata (Not State!)

Critical distinction: We store metadata ONLY (for user reference), not session state.

class SessionManager:
    """Lightweight session metadata storage."""

    def save_session_metadata(self, session_id: str, metadata: dict):
        """Save session metadata."""
        path = self.storage / f"{session_id}.json"
        metadata.update({
            "session_id": session_id,
            "created_at": datetime.now().isoformat(),
        })
        path.write_text(json.dumps(metadata, indent=2))

    def list_sessions(self) -> list[dict]:
        """List all sessions."""
        sessions = []
        for path in self.storage.glob("*.json"):
            sessions.append(json.loads(path.read_text()))
        return sorted(sessions, key=lambda s: s["created_at"], reverse=True)

50 lines vs app-cli's SessionStore: 479 lines (90% reduction)

Why so much smaller?

• Foundation handles session state during lifetime
• We only store metadata for user to remember context
• No atomic operations, backup files, corruption recovery
• "Resumption" = showing user past context, not restoring state

CLI Commands with Typer

Modern CLI framework with auto-completion and rich output:

import typer
from rich.console import Console

app = typer.Typer()
console = Console()

@app.command()
def run_prompt(
    prompt: str = typer.Argument(...),
    provider: Optional[str] = typer.Option(None, "--provider", "-p"),
    bundle: Optional[list[str]] = typer.Option(None, "--bundle", "-b"),
):
    """Execute a single prompt."""
    asyncio.run(_execute_prompt(prompt, provider, bundle))

async def _execute_prompt(prompt: str, provider: Optional[str], bundles: Optional[list[str]]):
    config = Config.from_env_and_project()
    if provider:
        config.provider = provider
    if bundles:
        config.bundles = list(bundles)

    async with AmplifierApp(config) as app:
        response = await app.execute(prompt)
        console.print(Markdown(response))

REPL Mode

Interactive mode using prompt_toolkit:

async def repl_mode():
    """Interactive REPL mode."""
    config = Config.from_env_and_project()
    config.validate()

    async with AmplifierApp(config) as app:
        history_file = Path.home() / ".amplifier" / "repl_history"
        prompt_session = PromptSession(
            history=FileHistory(str(history_file)),
            multiline=True,
        )

        while True:
            try:
                user_input = await prompt_session.prompt_async(">>> ")
                if user_input.lower() in ("exit", "quit"):
                    break

                response = await app.execute(user_input)
                console.print(Markdown(response))

            except KeyboardInterrupt:
                continue
            except EOFError:
                break

Foundation maintains context across all REPL inputs automatically!

Agent Commands

Direct spawn() usage (no wrapper needed):

@app.command(name="run")
def run_agent(
    agent: str = typer.Argument(...),
    instruction: str = typer.Argument(...),
    resume: Optional[str] = typer.Option(None, "--resume"),
):
    """Spawn an agent."""
    asyncio.run(_spawn_agent(agent, instruction, resume))

async def _spawn_agent(agent: str, instruction: str, resume_id: Optional[str]):
    config = Config.from_env_and_project()
    async with AmplifierApp(config) as app:
        agent_path = _resolve_agent_path(agent)
        result = await app.spawn_agent(
            agent_path,
            instruction,
            session_id=resume_id  # None = new, or ID to resume
        )
        console.print(Markdown(result["output"]))

Foundation handles agent resumption natively!

Bundle Commands

Inspect bundles using foundation's Bundle object:

@app.command()
def inspect(bundle_path: str):
    """Inspect bundle contents."""
    asyncio.run(_inspect_bundle(bundle_path))

async def _inspect_bundle(bundle_path: str):
    bundle = await load_bundle(bundle_path)

    console.print(f"{bundle.name} v{bundle.version}")
    if bundle.providers:
        console.print("\nProviders:")
        for p in bundle.providers:
            console.print(f"  • {p['module']}")

    if bundle.tools:
        console.print("\nTools:")
        for t in bundle.tools:
            console.print(f"  • {t['module']}")

Bundle object is self-documenting - no custom introspection needed!

Code Reduction Breakdown

Key Takeaways

Do:

• Use foundation APIs directly
• Let config files BE bundles
• Store only session metadata, not state
• Use bundle composition for all merging
• Leverage foundation features (mentions, caching, hooks)

Don't:

• Wrap foundation APIs (spawner, session store)
• Create custom config merging
• Try to persist session state
• Reimplement foundation features
• Copy app-cli internals

Pattern Summary:

Your CLI → AmplifierApp → foundation workflow
            ↓
         load → compose → prepare → session → execute
            ↑
      All heavy lifting done by foundation

The app layer is truly thin (typically ~1,500 LOC) - just CLI commands, config search, and metadata tracking.

File Reference

See references/ARCHITECTURE.md for foundation architecture.

External Documentation

• Foundation Concepts: https://github.com/microsoft/amplifier-foundation/blob/main/docs/CONCEPTS.md
• Common Patterns: https://github.com/microsoft/amplifier-foundation/blob/main/docs/PATTERNS.md
• CLI Blueprint: https://github.com/microsoft/amplifier-foundation/blob/main/examples/08_cli_application.py
• Profile Authoring: https://github.com/microsoft/amplifier-profiles/blob/main/docs/PROFILE_AUTHORING.md