Module settings 

Lightweight settings helpers: a secret-masking string newtype and a precedence-based value loader.

This mirrors upstream’s _settings.py, which replaced a pydantic-settings-based AFBaseSettings with a function-based loader (load_settings) plus a repr-masking SecretString. Rather than port the Python TypedDict-driven schema loader (which leans on runtime reflection that has no idiomatic Rust equivalent), this module provides the two reusable primitives:

• SecretString — a String newtype whose Debug/Display impls mask the value so secrets never leak into logs, while still (de)serializing to the real value and round-tripping through serde_json.
• load_setting — a single-value loader implementing the same precedence as upstream’s load_settings: explicit override, then a .env file, then the process environment, then a default.

Example

use agent_framework_core::settings::SecretString;

let key = SecretString::new("sk-super-secret");
assert_eq!(format!("{key}"), "***");
assert_eq!(format!("{key:?}"), "SecretString(\"***\")");
assert_eq!(key.expose_secret(), "sk-super-secret");

Structs

SecretString

A string wrapper that masks its value when printed via Debug or Display, to prevent secrets (API keys, tokens, passwords, …) from accidentally ending up in logs or error messages.

Functions

load_setting

Resolve a single setting value using the same precedence as upstream’s load_settings: