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FastroAI Changelog

Introduction

The Changelog documents all notable changes made to FastroAI. This includes new features, bug fixes, and improvements. It's organized by version and date, providing a clear history of the library's development.

[0.4.0] - Dec 20, 2025

Added

  • Enhanced Cost Tracking by @igorbenav
  • Cache token tracking (cache_read_tokens, cache_write_tokens) for accurate cost calculation with prompt caching
  • Audio token tracking for multimodal models
  • Request count tracking (request_count) for API call monitoring
  • Tool call count tracking (tool_call_count) for agentic behavior metrics

  • Provider-specific usage details (usage_details dict) for reasoning tokens, etc.

  • Accurate Prompt Caching Costs

  • Cached tokens are now priced at 90% discount (Anthropic) automatically
  • CostCalculator.calculate_cost() accepts optional cache_read_tokens, cache_write_tokens parameters
  • Pricing overrides support cache token rates via add_pricing_override(cache_read_per_mtok=..., cache_write_per_mtok=...)
  • Fixes cost overreporting when prompt caching is enabled (~18% more accurate)

Changed

  • All Pydantic schemas now use Field(description=...) for better API documentation
  • ChatResponse, StepUsage, and PipelineUsage include new usage fields with sensible defaults
  • Backward compatible - existing code continues to work without changes

Documentation

  • Updated FastroAgent guide with new response fields
  • Added Prompt Caching section to Cost Calculator guide
  • Updated API reference with enhanced schemas

Full Changelog: https://github.com/benavlabs/fastroai/compare/v0.3.0...v0.4.0

[0.3.0] - Dec 17, 2025

Added

  • LogfireTracer by @igorbenav
  • Built-in tracer implementation for Pydantic's Logfire observability platform
  • Implements the Tracer protocol - drop-in replacement for SimpleTracer
  • Automatic span creation with _tags=["fastroai"] for easy filtering in Logfire dashboard
  • Metric logging via logfire.info() with trace correlation
  • Error logging with full exception info via logfire.error()

  • Clear ImportError when logfire package is not installed

  • Optional Dependency by @igorbenav

  • Install with pip install fastroai[logfire] to enable Logfire support
  • Logfire remains optional - core functionality works without it

Documentation

  • Added LogfireTracer to built-in tracers section in tracing guide
  • Added LogfireTracer to API reference
  • Updated README with Logfire installation instructions

What's Changed

Full Changelog: https://github.com/benavlabs/fastroai/compare/v0.2.0...v0.3.0

[0.2.0] - Dec 16, 2025

Added

  • FastroAgent - PydanticAI wrapper with automatic cost calculation and tracing
  • Pipeline - DAG-based workflow orchestration with automatic parallelization
  • @step decorator - Concise function-based pipeline step definitions
  • @safe_tool - Production-safe tool decorator with timeout and retry
  • CostCalculator - Precise cost tracking using microcents (integer arithmetic)
  • Tracer Protocol - Protocol-based tracing interface for observability integration
  • SimpleTracer - Logging-based tracer for development
  • NoOpTracer - No-op tracer for testing or disabled tracing

Documentation

  • Complete documentation site with guides, API reference, and recipes
  • MkDocs Material theme with dark/light mode support

Full Changelog: https://github.com/benavlabs/fastroai/compare/v0.1.0...v0.2.0

[0.1.0] - Dec 15, 2025

Initial release.

  • Core FastroAgent functionality
  • Basic pipeline support
  • Cost calculation primitives