Show HN: Charter – Declare agent tools in Pydantic instead of implementing them

Category: devtools

Tags: agent-tools, pydantic, http-api, llm-agents, tool-validation

Score: 6.8/10 (Innovation: 6, Technical: 7, Documentation: 8, Utility: 6)

Charter is a Python library that lets developers define agent tools using annotated Pydantic models, enabling validation and request building for any HTTP API without writing glue code. It provides a declarative layer with field-level rules, projection/pinning for context control, and built-in formats, aiming to make agent tooling safer and more maintainable than vendor-toolkit or hand-wired approaches.

Target audience: backend developers, AI engineers building agent integrations

Repository: https://github.com/r28ai/charter · Python · Apache-2.0 · 4 stars

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