Aider (harness)
OSS terminal coding agent by Paul Gauthier — one of the original AI-pair-programmer CLIs (2023). Architect/Editor modes; repo-map for context; uses any LiteLLM-compatible model. Memory via CONVENTIONS.md and .aider.conf.yml — author-edited markdown. Distinct from the separate Aider memory-row in "Coding-agent memory"; this row characterises the harness itself.
Active · Verified 2026-10-31 · fresh as of 2026-10-31 · 51 cited facts, 2 with a third-party source · 1 recorded change · Suggest a correction
At a glance
- Type
- Terminal-native AI pair programmer (OSS, Python) vendor fix
- Tier
- T2
- Section
- Agent IDEs & coding harnesses
- Latest release
- v0.86.2 (2026-02-12) third-party fix
- License
- Apache-2.0 vendor fix
- GitHub
- Aider-AI/aider — ~49.7k stars, last commit 2026-02 (last push 2026-02-25 per ecosyste.ms) repo fix
- Pricing
- Free (OSS); usage via LLM provider vendor fix
- Funding
- OSS — no commercial entity vendor fix
- Freshness
- 2026-10-31 fix
- Layer
- agent-infra repo fix
- Licensing
- open-source vendor fix
- Developer activity
- OpenRank 8.86 (12-mo avg 9.78) · 130 participants — 2026-09 third-party fix
When to use
Optimised for: Architect/Editor split + repo-map context + multi-model via LiteLLM
Anti-fit: CLI-only; no GUI; primarily text editing — limited tool execution vs Claude Code
Pros & cons
Pros
Earliest-mover credibility; multi-model is real — switching from Claude to GPT to Gemini is a one-line config change; Aider edit-benchmark is widely cited.
Cons
Small dev team; trails newer agents on tool-use surface; weaker MCP ecosystem than Claude/Codex CLI.
Claims & capabilities
Among the earliest production-quality terminal coding agents; multi-model (Anthropic, OpenAI, Gemini, Ollama via LiteLLM).
Technical surface
- API surface
- CLI (Python)
- Backend storage
- local repo + CONVENTIONS.md
- Deployment
- Self-hosted only — local CLI (pip install aider-chat); BYO LLM provider
- Embedding model
- not applicable — not a memory product
- Multi-tenancy
- single-user (CLI)
- MCP
- no — no MCP client/server in Aider README or docs
- A2A
- searched not found
- OpenTelemetry
- searched not found
Alternatives to Aider (harness) → live options ranked by shared design, licence, hosting and MCP support
Similar systems
Other agent ides & coding harnesses in the catalog, ranked by inbound references.
- Claude Code (Anthropic) T1
Anthropic's agentic coding tool: Claude as a coding agent in the terminal, IDEs (VS Code, JetBrains), desktop app, web/mobile, GitHub and Slack. Context via CLAUDE.md, skills, hooks, subagents and MCP servers.
- Cursor (IDE) T1
AI-first IDE that forked VS Code; Composer (multi-file edit) and Agent Mode (long-running coding agent) are its flagship surfaces. Memory layer = .cursorrules / Rules; recall via repo-aware Context Engine. Anysphere (parent) raised $900M Series C at $9.9B in May 2025; acquired by SpaceX (announced 2026-08-14, terms undisclosed), product continues under the Cursor brand.
- OpenAI Codex CLI T1
OpenAI's actively developed OSS terminal coding agent (Apr 2025), now written in Rust (codex-rs replaced the original TS CLI); also IDE extension + desktop app. Separate from the Codex Web cloud agent and the retired 2021 Codex model API. The codex mcp-server command (Codex as an MCP server) was deprecated on 2026-08-24 and removed in CLI 0.154.0 (2026-09-09); OpenAI points integrations to the experimental Codex app server, and codex mcp still connects Codex to external MCP servers.
- Opencode (SST) T2
SST team's open-source terminal coding agent — TypeScript, multi-model, MCP-native. Released 2025; explicitly positioned as a permissively-licensed Claude Code alternative. Memory via AGENTS.md (the emerging cross-harness convention).
- Bedrock AgentCore (AWS) T2
AWS Bedrock AgentCore — managed runtime to deploy + scale + observe agents. Multi-component: Runtime, Identity, Memory, Gateway, Browser, Code Interpreter, Observability. Distinct from Bedrock Agents (older fixed-config product); AgentCore is the 2025 framework-agnostic runtime for any agent (LangGraph, CrewAI, Strands, OpenAI Agents SDK).
- GitHub Copilot (Agent Mode) T1
The original AI coding assistant (Copilot in editor; 2021). 2025 evolved into a full agentic surface: chat, completions, Agent Mode (multi-step), and Copilot Workspace. Backed by Microsoft. Distinct row from Workspace — this row covers the everyday in-editor + agent mode product, Workspace covers the hosted spec-driven workflow.
Sources (50 cited facts, 2 third-party)
Each fact links to the page it came from; the badge says who published it (how to read sources).
- What it is Terminal-native AI pair programmer (OSS, Python) vendor
- What it does & what's distinct OSS terminal coding agent by Paul Gauthier — one of the original AI-pair-programmer CLIs… vendor
- Claims / benefits Among the earliest production-quality terminal coding agents; multi-model (Anthropic, Op… vendor
- Modalities text vendor
- Created 2023-05 vendor
- Latest release v0.86.2 (2026-02-12) third-party
- License Apache-2.0 vendor
- GitHub Aider-AI/aider — ~49.7k stars, last commit 2026-02 (last push 2026-02-25 per ecosyste.ms) repo
- Mindshare 20+ HN threads since 2023; consistent top of weekly "AI coding tools" comparison posts vendor
- Funding OSS — no commercial entity vendor
- Customers / scale OSS — broad community adoption; indie devs over-indexed vendor
- Pricing Free (OSS); usage via LLM provider vendor
- Compliance OSS — no formal compliance vendor
- Data handling Local CLI; LLM calls go through user's chosen provider vendor
- Deployment Self-hosted only — local CLI (pip install aider-chat); BYO LLM provider vendor
- HQ US (independent; Paul Gauthier) vendor
- Founders / pedigree Paul Gauthier (ex-MIT; ex-Inktomi) vendor
- Memory volume / scale no scale claim vendor
- Performance Leaderboard at aider.chat/docs/leaderboards/ — Aider edit-benchmark vendor
- Code/weights release Open-source — github.com/Aider-AI/aider vendor
- API surface CLI (Python) vendor
- Backend storage local repo + CONVENTIONS.md vendor
- Multi-tenancy single-user (CLI) vendor
- Encryption TLS for LLM API vendor
- Versioning CONVENTIONS.md in git vendor
- Schema evolution free-form / no schema vendor
- Namespace primitives per-repo vendor
- Contradiction handling human-arbitrate vendor
- MCP support no — no MCP client/server in Aider README or docs repo
- Import / export CONVENTIONS.md is plain markdown vendor
- Validated verticals coding agents — broad horizontal vendor
- Time to running <10min (`pip install aider-chat`) vendor
- Anti-fit CLI-only; no GUI; primarily text editing — limited tool execution vs Claude Code vendor
- Optimised for Architect/Editor split + repo-map context + multi-model via LiteLLM vendor
- Adjacent infrastructure LiteLLM for model routing vendor
- Pros Earliest-mover credibility; multi-model is real — switching from Claude to GPT to Gemini… vendor
- Cons Small dev team; trails newer agents on tool-use surface; weaker MCP ecosystem than Claud… vendor
- Project & sources aider.chat; github.com/Aider-AI/aider vendor
- download-trajectory [{"ym":"2025-11","monthly":141220,"cum":141220},{"ym":"2025-12","monthly":221453,"cum":3… registry
- cost-input-usd-per-mtok 0 vendor
- cost-output-usd-per-mtok 0 vendor
- cost-tier free vendor
- cost-pricing-model free-tier vendor
- cost-last-verified 2026-06-29 vendor
- capability-benchmark-sources aider-polyglot: 88.0% (gpt-5 (high), diff edit format, leaderboard entry 2025-08-23) htt… vendor
- architecture-deployment-locus local vendor
- licensing-bucket open-source vendor
- positioning-platform-vs-product product vendor
- taxonomy-three-layer-rollup agent-infra repo
- developer-activity-opendigger {"activity":205.86,"as_of":"2026-09","openrank_12mo":9.78,"openrank_current":8.86,"parti… third-party
What changed
Changes to this record's lifecycle, licence, release, pricing and hosting facts, from the catalog's git history. Subscribe (Atom)
- 2026-10-26
- Latest release “aider 0.x rolling (2025-2026)” → “v0.86.2 (2026-02-12)” source
- Deployment “Self-host (pip install aider-chat)” → “Self-hosted only — local CLI (pip install aider-chat); BYO LLM provider” source
- MCP support “depth-floor — Aider primarily uses its own tool-call format; MCP support tracked in issues” → “no — no MCP client/server in Aider README or docs” source
Related systems
References (1)
- LiteLLM depends on at runtime — uses any LiteLLM-compatible model. Memory via CONVENTIONS.md and .aider.conf.yml — author-edited markdown.