Table of Contents

• Overview
• When to Use
• Core Concepts
• Service Configuration
• Execution Result
• Quick Start
• Register Services
• Execute via Service
• Health Checks
• Service Selection
• Auto-Selection
• Failover Pattern
• Integration Pattern
• Detailed Resources
• Exit Criteria

Service Registry

Overview

A registry pattern for managing connections to external services. Handles configuration, health checking, and execution across multiple service integrations.

When To Use

• Managing multiple external services.
• Need consistent execution interface.
• Want health monitoring across services.
• Building service failover logic.

When NOT To Use

• Single service integration without registry needs

Core Concepts

Service Configuration

@dataclass
class ServiceConfig:
    name: str
    command: str
    auth_method: str  # "api_key", "oauth", "token"
    auth_env_var: str
    quota_limits: dict
    models: list[str] = field(default_factory=list)

Verification: Run the command with

--help

flag to verify availability.

Execution Result

@dataclass
class ExecutionResult:
    success: bool
    stdout: str
    stderr: str
    exit_code: int
    duration: float
    tokens_used: int

Verification: Run the command with

--help

flag to verify availability.

Quick Start

Register Services

from leyline.service_registry import ServiceRegistry

registry = ServiceRegistry()

registry.register("gemini", ServiceConfig(
    name="gemini",
    command="gemini",
    auth_method="api_key",
    auth_env_var="GEMINI_API_KEY",
    quota_limits={"rpm": 60, "daily": 1000}
))

Verification: Run the command with

--help

flag to verify availability.

Execute via Service

result = registry.execute(
    service="gemini",
    prompt="Analyze this code",
    files=["src/main.py"],
    model="gemini-2.5-pro"
)

if result.success:
    print(result.stdout)

Verification: Run the command with

--help

flag to verify availability.

Health Checks

# Check single service
status = registry.health_check("gemini")

# Check all services
all_status = registry.health_check_all()
for service, healthy in all_status.items():
    print(f"{service}: {'OK' if healthy else 'FAILED'}")

Verification: Run the command with

--help

flag to verify availability.

Service Selection

Auto-Selection

# Select best service for task
service = registry.select_service(
    requirements={
        "large_context": True,
        "fast_response": False
    }
)

Verification: Run the command with

--help

flag to verify availability.

Failover Pattern

def execute_with_failover(prompt: str, files: list) -> ExecutionResult:
    for service in registry.get_healthy_services():
        result = registry.execute(service, prompt, files)
        if result.success:
            return result
    raise AllServicesFailedError()

Verification: Run the command with

--help

flag to verify availability.

Integration Pattern

# In your skill's frontmatter
dependencies: [leyline:service-registry]

Verification: Run the command with

--help

flag to verify availability.

Detailed Resources

• Service Config: See

  modules/service-config.md

  for configuration options.
• Execution Patterns: See

  modules/execution-patterns.md

  for advanced usage.

Exit Criteria

• Services registered with configuration.
• Health checks passing.
• Execution results properly handled.