Aider: Terminal Pair Programming, Context and Model Costs
What does Aider do?
Aider is a terminal-based pair-programming tool for working on new or existing code. The official site describes repository mapping, Git integration, multi-file edits and optional linting and testing. It connects to cloud or local models. That combination suits developers who want a conversational editing workflow while keeping their normal editor and Git review process.
How should you choose context?
The FAQ advises adding the files that need editing instead of sending the entire repository. A compact repository map provides broader context. For a large monorepo, narrow the working scope and inspect ignore settings. More input is not automatically better: irrelevant code increases model cost and can obscure the function or interface you actually want changed.
What does it cost?
Separate the tool from the selected model. Cloud API charges depend on provider, input context and generated output; local inference requires suitable hardware and operating resources. This profile does not establish a universal per-task price. Record total session spend, including failed edits and repeated tests, rather than comparing only the first model response.
What is a useful first task?
Use a disposable copy of a small repository and ask for a CSV parser to accept quoted commas without changing existing handling of empty fields. Supply a fixture and expected output. Request a short explanation of the intended edit before applying it. Review the complete diff and run the existing parser tests plus the quoted-comma case.
What should acceptance require?
The new fixture must pass, old fixtures must still pass, and unrelated modules should remain unchanged. Check the resulting commit history because the documented Git integration can create commits. A successful commit proves a change was recorded, not that it is correct. Preserve your own uncommitted work before starting and avoid sharing secrets in code or chat context.
Which alternatives fit?
Compare Cline for a Plan-and-Act workflow and Cursor for an editor-centered experience. Compare the same bounded bug fix, counting correction time and reviewing which files and commands each tool can access.
Sources checked October 28, 2026: Product · Context guidance · Model connections.