Aider

Type: full-code · Vendor: Paul Gauthier / Aider-AI community · Language: Python · License: Apache-2.0 · Status: active · Status in practice: mature · First released: 2023-05-09

Links: homepage docs repo

Open-source terminal-native AI pair-programmer that edits files in a git repo through diff-formatted edits, auto-commits each change, and works with almost any LLM provider.

Description. Aider runs in the terminal, takes natural-language requests, and applies them as diffs to files in your git repo. Every edit is auto-committed with a descriptive message so you can review via standard git tools and use /undo to roll back. A concise repo map of classes/functions is sent with each request so the model has whole-codebase awareness. Aider supports cloud and local models, prompt caching on supported providers, voice input, image input, automatic lint+test loops, and an 'architect' mode that splits planning from editing across two models.

Agent loop shape. Single-agent loop built around git as substrate. User types a request → Aider consults the repo-map → selects an edit format (whole-file, diff, udiff, search-replace) appropriate to the model → emits edits → applies them to files → optionally runs --lint-cmd and --test-cmd → tries to fix any non-zero exit → commits to git. /undo rewinds the last commit. Architect mode runs a planning model first, then hands the proposal to a faster editor model.

Primary use cases

terminal-native AI pair-programming in a git repo
diff-formatted edits with auto-commit and /undo
architect+editor multi-model splits
auto-lint and auto-test feedback loops

flowchart TD user[User request] --> repomap[Repo-map sent to LLM] repomap --> mode{Mode} mode -->|code| llm[LLM emits diff] mode -->|architect| arch[Architect LLM plan] arch --> edit[Editor LLM emits diff] edit --> llm llm --> apply[Apply diff to files] apply --> lint[Auto-lint] lint --> test[Auto-test] test --> fix{Errors?} fix -->|yes| llm fix -->|no| commit[Git auto-commit] commit --> done[Ready] done -.->|/undo| revert[Git revert]

Key concepts

Edit formats (docs) — Model emits diffs (whole-file / diff / udiff / search-replace) Aider parses and applies.
Repo-map → agentic-rag (docs) — Graph-optimised concise map of the whole repo sent to the LLM.
Git as memory → replay-time-travel (docs) — Every edit is a commit; /undo is git revert.
Modes (code/ask/architect/help) → multi-model-routing (docs) — Architect+editor split is the multi-model loop.
Prompt caching → prompt-caching (docs) — Caches system prompt, read-only files, repo map, editable files.
Auto lint + auto test → code-execution (docs) — Automatic feedback loop after every edit.

Aider

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References

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