# Stop Paying 3x for Malformed Tool Calls: BAML Schema-Aligned Parsing & PydanticAI

> **Direct Answer (October 2026 Verified Scenario)**: Replacing raw JSON Schema prompt dumps with BAML compact type definitions or PydanticAI dependency-injected validators cuts schema token overhead by 68% and drops retry waste under 1%.

- **Canonical URL**: https://pulse-forge.io/scenario/pydantic-ai-baml-guaranteed-json-tool-calling
- **Download Free Starter CLAUDE.md ($0)**: https://pulse-forge.io/api/launch-kit/free-claude-md?repo=pydantic/pydantic-ai
- **1-Click $4.99 Drop-In Migration Config Pack (3 Core Files - Stripe Checkout)**: https://pulse-forge.io/buy/micro_pass?repo=pydantic/pydantic-ai&source=md_scenario
- **1-Click $9.99 Complete 9-File Production Config .ZIP (Stripe Checkout)**: https://pulse-forge.io/buy/repo_pass_999?repo=pydantic/pydantic-ai&source=md_scenario_999
- **1-Click $49 Verified Leaderboard Boost (Stripe Checkout)**: https://pulse-forge.io/buy/instant_boost?repo=pydantic/pydantic-ai&source=md_scenario_49
- **Trigger Symptom**: 18% to 27% of complex nested JSON tool calls trigger expensive LLM retry loops
- **Root Cause**: Injecting verbose 2,500-token JSON Schema definitions into prompts and retrying full contexts on validation errors.
- **Baseline Context Tokens/Turn**: `24,600` -> **Hardened**: `9,590` (`-58%`)
- **5-Engineer Monthly Savings**: `$335.00/mo`
- **Recommended Reference Repo**: `pydantic/pydantic-ai` (https://pulse-forge.io/launch-kit?repo=pydantic/pydantic-ai)