PromptBind

PromptBind lets you bind prompts to functions and methods with a small decorator and TOML sidecar files. It keeps prompts close to your code, supports optional Jinja2 rendering, and allows hot-swapping prompt keys at runtime.

Installation

pip install promptbind

QuickStart

1. Create a prompt file next to your Python module (same name, .toml extension):

# example.toml
[greet]
prompt = "Hello, {{ name }}!"
use_jinja2 = true

[farewell]
prompt = "Goodbye."
use_jinja2 = false

2. Bind prompts to functions with the decorator. By default the prompt key is the function __qualname__, but you can override it with key=....

# example.py
from promptbind import with_prompt, PromptEntry

@with_prompt()
def greet(prompt: PromptEntry) -> str:
    return prompt.render(name="Ada")

@with_prompt(key="farewell")
def bye(prompt: PromptEntry) -> str:
    return prompt.render()

if __name__ == "__main__":
    print(greet())  # -> Hello, Ada!
    print(bye())    # -> Goodbye.

3. Patch prompt keys at runtime if you want to swap to another entry in the same TOML file:

from promptbind import set_prompt_key_patch, unset_prompt_key_patch

set_prompt_key_patch(greet, "farewell")  # greet now uses the farewell prompt
print(greet())  # -> Goodbye.
unset_prompt_key_patch(greet)            # revert to original key

How it works

• A .toml file lives next to each Python file and stores prompt entries.
• with_prompt checks the TOML at import time, injects the matching PromptEntry, and routes calls to your function with prompt as the first argument (methods get self/cls first, then prompt).
• PromptEntry.render(**kwargs) renders with Jinja2 when use_jinja2 = true; otherwise it returns the raw string (passing kwargs in that case is a no-op).

Thread safety note

set_prompt_key_patch/unset_prompt_key_patch mutate shared process-wide state. Avoid calling them concurrently across threads, or you may observe races where a call picks up the wrong prompt key. If you must patch in a multithreaded context, guard these calls with your own locking.

Minimal project layout

project/
├─ example.py
└─ example.toml

That is all you need to start binding prompts to your code. See test/example.py and test/example.toml in the repo for a runnable sample.