ABK (Agent Builder Kit)

Modular utilities for building LLM agents

ABK is a feature-gated Rust crate providing essential utilities for building LLM-based agents. Choose only the components you need via Cargo features.

Features

ABK provides three main feature modules:

config - Configuration Management

• TOML configuration file parsing
• Environment variable loading via .env files
• Type-safe configuration structures
• Path resolution helpers
• Validation and defaults

observability - Logging & Metrics

• Markdown-formatted logging for agent sessions
• LLM interaction tracking
• Command execution logging
• Tool execution logging
• Session lifecycle management
• Debug-level message inspection

cli - CLI Display Utilities

Coming soon - will be extracted from simpaticoder

• Panel and message box rendering
• Time formatting utilities
• Text truncation and formatting
• Color and styling helpers

Installation

Add to your Cargo.toml:

[dependencies]
# Enable only the features you need:
abk = { version = "0.1", features = ["config"] }

# Or enable multiple features:
abk = { version = "0.1", features = ["config", "observability"] }

# Or enable everything:
abk = { version = "0.1", features = ["all"] }

Usage

Configuration Feature

use abk::config::{ConfigurationLoader, EnvironmentLoader};
use std::path::Path;

// Load environment variables
let env = EnvironmentLoader::new(None);

// Load configuration from TOML
let config_loader = ConfigurationLoader::new(
    Some(Path::new("config/simpaticoder.toml"))
).unwrap();
let config = &config_loader.config;

// Access configuration
println!("Max iterations: {}", config.execution.max_iterations);
println!("LLM provider: {:?}", env.llm_provider());

Configuration Structure

The Configuration struct includes:

• Agent: Core agent settings (name, version, user agent)
• Templates: Template paths and settings
• Logging: Logging configuration (level, format, targets)
• Execution: Execution limits (timeout, retries, max iterations)
• Modes: Operation modes (auto-approve, dry-run, verbose)
• Tools: Tool-specific configuration (file window size, result limits)
• Search Filtering: Directory and file filtering for search operations
• LLM: LLM provider configuration (endpoint, streaming)

Environment Variables

The EnvironmentLoader handles:

• .env file loading (if provided)
• System environment variable access
• Provider selection via LLM_PROVIDER

Observability Feature

use abk::observability::Logger;
use std::collections::HashMap;

// Create a logger with custom path and log level
let logger = Logger::new(
    Some(Path::new("logs/agent.md")),
    Some("DEBUG")
).unwrap();

// Or use default (temp directory, INFO level)
let logger = Logger::default();

// Log a session start
let config = HashMap::new();
logger.log_session_start("auto", &config).unwrap();

// Log LLM interactions
let messages = vec![]; // Your message history
logger.log_llm_interaction(&messages, "Response text", "gpt-4").unwrap();

// Log command executions
logger.log_command_execution(
    "cargo build",
    "Compiling...",
    "",
    0,
    "auto"
).unwrap();

// Log tool executions
logger.log_tool_execution(
    "search_file",
    r#"{"pattern":"Logger"}"#,
    "Found 5 matches",
    true
).unwrap();

// Log completion
logger.log_completion("Task completed successfully").unwrap();

Roadmap

ABK is part of the larger Trustee ecosystem extraction from simpaticoder.

• ✅ Phase 1: config feature (v0.1.0 - extracted from trustee-config)
• ✅ Phase 2: observability feature (v0.1.1 - extracted from simpaticoder/src/logger)
• ⏳ Phase 3: cli feature (extracting from simpaticoder/src/cli/commands/utils.rs)

Why ABK?

Instead of maintaining separate trustee-config, trustee-observability, and trustee-cli crates, ABK unifies them under one package with feature flags. This provides:

• Unified versioning - One version number for all infrastructure utilities
• Simplified dependencies - Import one crate instead of three
• Modular builds - Only compile what you use
• Coordinated releases - Breaking changes managed together

License

Dual-licensed under MIT OR Apache-2.0