:PROPERTIES:
:ID:       c3aab2e8-7e43-4abc-93f0-741675cfd78c
:CREATED:  [2026-05-22 Thu]
:END:
#+title: Aider — AI Coding Agent
#+filetags: :passepartout:strategy:competitive:aider:

Language: Python. ~6.8M pip installs. ~40K lines. MIT license. The oldest and most mature open-source coding agent.

Architecture: Chat-based Coder class with 5 edit formats (diff, udiff, patch, whole, architect). Uses litellm for universal provider access (50+ providers). RepoMap provides codebase awareness via cosine-similarity embedding.

Safety model: Purely prompt-based plus user-confirmation dialogs. No deterministic gate stack. No sandboxing. No model output validator. The allowed_to_edit() gate is a single user confirmation call. --yes flag auto-approves. Aider can edit its own source code with no special protection — self-modification is undetectable.

Data model: Ad-hoc. Chat messages in memory. Git commits for persistence. RepoMap is a cosine-similarity index. No persistent memory across sessions. No knowledge graph.

Self-modification: Full. No guard against editing its own files.

Verification: None.

Key gap vs Passepartout: No safety gates, no persistent memory model, no knowledge representation, no verification, no self-modification protection, no architecture for neurosymbolic reasoning. It is a thin shell around litellm + edit format parsers.

See the full [[id:3aa22300-2f25-57b0-8787-9f199cc978b1][competitive analysis]] for the landscape view and comparison.