vial-ml 0.1.2

Surgical code isolation for AI agents

Vial

Surgical code isolation for AI agents.

Vial extracts a single function or class from a large Python file into a clean, focused workspace file so an agent only sees — and edits — exactly what it needs to.

Install

pip install vial-ml
# or with uv:
uv add vial-ml

CLI

# Isolate a function
vial extract billing.py process_payment

# Agent edits .vial_workspace/process_payment_isolated.py ...

# Stitch it back (validates syntax first)
vial merge

Python API

from vial import Vial

v = Vial()
isolated_path = v.extract("billing.py", "process_payment")
# agent edits isolated_path ...
v.merge()

Why

When an agent reads a 2,000-line file to fix a 20-line function it wastes tokens, risks editing the wrong code, and produces complex diffs that frequently fail. Vial reduces the context to only what matters, cutting token usage by 71–88% on typical files.

How it works

1. Extract — AST-based line-bound finder locates the exact start/end of the target. A protected context header (imports + module-level globals, commented out) is prepended so the agent has the context it needs without being able to accidentally modify it.
2. Edit — The agent modifies only the isolated file.
3. Merge — Vial validates the modified code's syntax, then splices it back into the original file at the exact line range. Surrounding code is never touched.

All session state lives in a metadata.json file inside the workspace directory.