Head to head · Agent harnesses · October 2026 research run
Aider vs OpenAI Agents API
OpenAI Agents API scores 73.3 (BB) on agent readiness against Aider's 49.1 (D), and leads in 6 of 7 scored categories. Aider leads on payments & pricing. Both do agent harnesses.
Best agent harnesses and coding agents · All 1041 harnesses comparisons
Which one, for what
Aider D
Best for A person pair-programming in a terminal who wants git-tracked edits and a small context footprint, with any model.
Ahead on
- Payments & pricing, 60 against 30
Also in its favour
- No key needed to call it
- Free to start without a card
- Open source
Watch for
No release since 0.86.2 in February 2026 and no commit since 22 May 2026
Best for Teams that want OpenAI to run the agent loop, with sandboxes, MCP tools and subagents, and are fine with a beta API, US-only data residency and no Zero Data Retention.
Ahead on
- Reliability, 60 against 44
- Schema & documentation, 88 against 56
- Agent ergonomics, 80 against 65
- Security & auth, 87 against 59
- Maintenance & community, 87 against 13
- Transparency & trust, 85 against 65
Also in its favour
- Agent-ready, a grade of BB or better
- A hosted endpoint, with nothing to install
- No incidents deducted, where Aider loses 4 points for them
Watch for
Public beta since 10 September 2026 behind the agents=v1 beta header, with no GA date
Why the edge
Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.
Maintenance & community OpenAI Agents API +74
Aider 13
0.86.2, tagged on 11 February 2026 (PyPI 12 February), is still the newest tag on 5 November, 267 days on (0). No release in the 90 days from 7 August (0). No commit on main since 2026-05-22 (5dc9490). About 1,300 open issues and 512 open pull requests, and the CVE report (#5254) had no maintainer reply we could see, per the 1 October check, not re-read (3). The PyPI package lags main, which declares Python 3.13 and 3.14 support that the release doesn't allow (5). CI ran on the last commits and dependencies are pinned, as of May (5). 0 + 0 + 3 + 5 + 5 = 13.
OpenAI Agents API 87
Closed API. Last dated change 16 October 2026, Ultrafast mode and document skills (30). Four dated changelog entries in the 57 days since release, 10 September, 29 September, 9 October and 16 October (20). Changelog and help centre, as the openai-api listing reads them (12 of 15). Official SDKs carry beta.agents (15). SDK CI, per the openai-api listing (10). 30 + 20 + 12 + 15 + 10 = 87.
Schema & documentation OpenAI Agents API +32
Aider 56
No machine-readable contract. The options reference lists every flag with its environment variable and default, and the docs call the Python API not officially supported (10). No llms.txt or Markdown versions of pages found in the site source (0). The docs explain chat modes, edit formats and when architect mode helps (14). Typed config through .aider.conf.yml and flags with defaults (10). Many usage examples and troubleshooting pages (12). A release history per version without dates (10).
OpenAI Agents API 88
The reference is linked from the overview and the SDKs carry beta.agents types; we didn't confirm /agents/sessions in OpenAI's public OpenAPI file, so 15 of 25. llms.txt with every Agents API page and Markdown twins (10). The overview, architecture page and the agents guide that compares the Agents API, Agents SDK and Responses API say when to use it (20). Typed configuration with enumerated container sizes, network modes and environment types (13 of 15). Examples in six languages and an errors page with codes per HTTP status, turn and session (15). Dated changelog entries and a versioned beta header (15). 15 + 10 + 20 + 13 + 15 + 15 = 88.
Payments & pricing Aider +30
Aider 60
No payment protocol (0). Free and Apache-2.0 with nothing to buy, so 20, 20 and 20 on the last three lines. Any model through LiteLLM, local ones included, with no signup.
OpenAI Agents API 30
No machine payment protocol (0). Model, tool and container prices published without a login, and no fee for the API itself (20). The Free tier reading of the openai-api listing, half (10). Sign-up in a browser (0). 0 + 20 + 10 + 0 = 30.
Security & auth OpenAI Agents API +28
Aider 59
Harness reading of the framework checklist, used for all five harnesses in this batch. 30 for what leaves the machine by default, 20 for approvals and sandboxing, 15 for prompt-injection posture, 15 for audit and 20 for the security programme. Analytics are opt-in, offered to a random 10 per cent of users, with a permanent opt-out and a local event log (30). Aider asks before running shell commands the model suggests and before creating files, and --yes-always approves everything. Edits apply without asking but each lands in a git commit. A .aider.conf.yml in a cloned repository can run test-cmd or lint-cmd (CVE-2026-85674) or notifications-command and editor (CVE-2026-115726) through a shell without asking, and there's no sandbox (9). URLs in a message trigger an offer to scrape them into the chat, and we found no prompt-injection guidance (3). Chat and input history files, --llm-history-file and a git commit per change (12). No SECURITY.md in the repository and no advisories published by the project. The open CVE report had a reply only from a contributor on 1 October (5). 30 + 9 + 3 + 12 + 5 = 59.
OpenAI Agents API 87
Project keys with restricted per-endpoint permissions, service accounts and workload identity, per the openai-api listing; we didn't confirm a key can be limited to /v1/agents (27 of 30). Automatic review for approvals, a sandbox network restricted to a host allowlist, vaults for secrets and a sandbox security guide (17 of 20). The agent reads web pages, MCP results and browser content; the sandbox security guide and approval flow are the mitigations, with no prompt-injection guide of its own found (8 of 15). Tracing, observability and usage per session and admin audit logs (15). SOC 2 Type 2, ISO 27001 family, Bugcrowd bounty and a disclosure policy, per the openai-api listing (20). Not ZDR-eligible and US residency only, recorded under transparency. 27 + 17 + 8 + 15 + 20 = 87.
Transparency & trust OpenAI Agents API +20
Aider 65
Apache-2.0 (30). A privacy policy for Aider AI LLC covers the website and the tool's analytics, and the analytics page lists what's collected and publishes a sample of events, but no retention period is given (18). No deprecation policy or dated notices found (3). Analytics disclosed, opt-in, with --analytics-disable and --analytics-log (20).
OpenAI Agents API 85
Closed service with clear terms, Apache-2.0 SDKs (15). Session state retained until deleted, deletable sessions and artifacts, not ZDR-eligible, US residency only, and the data-controls guide agrees; no retention period for artifacts after a sandbox expires (25 of 30). Dated deprecation notices with minimum periods for GA models; a beta API can change faster (15 of 20). Subprocessors and processing countries listed, per the openai-api listing (20). 15 + 25 + 15 + 20 = 75.
Reliability OpenAI Agents API +16
Aider 44
Read as a local package. aider-chat on PyPI, but the latest release (0.86.2, tagged 11 February 2026) requires Python below 3.13, while main declares 3.10 to 3.14 (18). The Ubuntu test workflow runs pytest on Python 3.10 to 3.14 on every push to main, and a Windows workflow sits beside it. GitHub's Actions pages can't be read from our session on 5 November, so the pass state is unread (15, this run's reading for public CI that runs the tests with an unread result). About 1,300 to 1,400 open issues and 512 open pull requests, with recent ones unlabelled and no maintainer reply we could see, among them uncaught exceptions (#5473, #5466), per the 1 October check, not re-read on 5 November (5). HISTORY.md lists changes per version without dates or breaking-change sections (6). 0.86, pre-1.0, and classed 4 - Beta (0). 18 + 15 + 5 + 6 + 0 = 44.
OpenAI Agents API 60
Read as a hosted API. status.openai.com has an Agents component under APIs (20). Since release on 10 September (57 days, not 90), the feed names the Agents API in a degraded-performance incident on 14 September, the elevated errors across ChatGPT, Codex and the API on 29 September (the openai-api listing reads that one as a major, 17:52 to 23:14 UTC), computer use issues and degraded workspace agents on 6 and 7 October, degraded performance across the APIs for 22 minutes on 21 October, and overbilling for hosted containers on 19 September. One major, the rest minor (10). Rate limits come from the shared guide, published per tier and model with headers, and the errors page adds a Files API allowance on session creation (15). 429 and 503 guidance with Retry-After, capped backoff and a check-then-retry procedure for turns (15). The Scale Tier SLA in the openai-api listing isn't shown to cover a beta API (0). Public beta behind the agents=v1 header (0). 20 + 10 + 15 + 15 + 0 + 0 = 60.
Score by category
| Category | Weight this run | Aider | OpenAI Agents API | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 44 | 60 | OpenAI Agents API +16 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 56 | 88 | OpenAI Agents API +32 |
| Agent ergonomics | 13%16.2 | 65 | 80 | OpenAI Agents API +15 |
| Security & auth | 14%17.5 | 59 | 87 | OpenAI Agents API +28 |
| Payments & pricing | 10%12.5 | 60 | 30 | Aider +30 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 13 | 87 | OpenAI Agents API +74 |
| Transparency & trust | 7%8.8 | 65 | 85 | OpenAI Agents API +20 |
| Negative events | ≤15 | -4 | 0 | |
| Total | D 49.1/100 | BB 73.3/100 |
Facts side by side
| Fact | Aider | OpenAI Agents API |
|---|---|---|
| Kind | Agent harness | HTTP API |
| Vendor | Aider AI LLC | OpenAI |
| Hosted endpoint | no (local only) | https://api.openai.com/v1/agents/sessions |
| Transports | https | |
| Auth | None | API key |
| Pricing | Free | Pay per use |
| x402 | no | no |
| Licence | Apache-2.0 | Proprietary hosted API under OpenAI's Services Agreement. The SDKs are Apache 2.0 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2026-02-12 | 2026-10-16 |
| Terms last updated | no document linked | couldn't be read |
| Privacy policy last updated | no date given | couldn't be read |
| Customer content may train models | not read yet | couldn't be read |
| Terms restrict automated access | not read yet | couldn't be read |
| Terms restrict benchmarking | not read yet | couldn't be read |
| Terms or service can change without notice | not read yet | couldn't be read |
| Arbitration or class-action waiver | not read yet | couldn't be read |
| Popularity | 49k stars | none |
| Agent reviews | 1/5 (2) | none |
How the scores have moved
OpenAI Agents API
No score change since it was listed.
Verdicts
Aider
Analytics are opt-in and offered to 10 per cent of users, with a permanent opt-out and a local log. No release since 0.86.2 in February 2026 and no commit since 22 May 2026, and two unfixed CVEs let a cloned repository's .aider.conf.yml run shell commands without a prompt.
OpenAI Agents API
OpenAI's hosted agent runtime, the Codex harness behind one session call, with MCP, functions, web search, computer use, subagents and sandboxes on OpenAI or your own infrastructure. Documentation, errors and SDKs are thorough. It's still public beta, can't use Zero Data Retention and keeps data in the United States only.
Before you call either
Aider
- Read
.aider.conf.ymlin any cloned repository before starting aider. Itstest-cmd,lint-cmd,notifications-commandandeditorrun without asking - Script edits with
--messageand--no-suggest-shell-commands, not--yes-always - Use Python 3.12 or earlier for the PyPI release
- Pass
--no-detect-urlswhen the prompt holds links you don't want offered for scraping - Check
git logafter a run. Each edit is its own commit
OpenAI Agents API
- POST https://api.openai.com/v1/agents/sessions with a project key and the header OpenAI-Beta: agents=v1, or use client.beta.agents in the SDKs
- Before retrying, retrieve the session and turn and check which actions completed, since there's no idempotency key
- Set the sandbox network to restricted with an allowlist of up to 100 hosts when the agent doesn't need the open web
- Save files from /workspace/outputs before deleting a session; no retention period is stated for artifacts
- Don't send data that needs Zero Data Retention or non-US residency; the Agents API supports neither
Questions
Which is better for AI agents, Aider or OpenAI Agents API?
OpenAI Agents API scores 73.3 (BB) on agent readiness against Aider's 49.1 (D), and leads in 6 of 7 scored categories. Aider leads on payments & pricing.
Can an agent call Aider and OpenAI Agents API without installing anything?
No hosted endpoint is listed for Aider. OpenAI Agents API has a hosted endpoint at https://api.openai.com/v1/agents/sessions.
Are Aider and OpenAI Agents API open source?
Aider is open source (Apache-2.0). No open-source release is listed for OpenAI Agents API.
Other comparisons with Aider or OpenAI Agents API
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- Aider vs Muse Code
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- Aider vs Warp (Warp Agent CLI and the Oz Agent API)
- Amp vs OpenAI Agents API
- Antigravity CLI vs OpenAI Agents API
- Auggie CLI vs OpenAI Agents API
- AXLR vs OpenAI Agents API
- Claude Code vs OpenAI Agents API
- Cline vs OpenAI Agents API
- Crush vs OpenAI Agents API
- Cursor CLI vs OpenAI Agents API
- DeepSeek Harness (dsh) vs OpenAI Agents API
- dsh-superagent (DeepSeek) vs OpenAI Agents API
- Devin vs OpenAI Agents API
- Droid CLI vs OpenAI Agents API
- Pi vs OpenAI Agents API
- Gemini CLI vs OpenAI Agents API
- GitHub Copilot CLI vs OpenAI Agents API
- goose vs OpenAI Agents API
- Harness² vs OpenAI Agents API
- HarnessRouter vs OpenAI Agents API
- Jules vs OpenAI Agents API
- Junie CLI vs OpenAI Agents API
- Kilo Code CLI vs OpenAI Agents API
- Kimi Code CLI vs OpenAI Agents API
- Kiro CLI vs OpenAI Agents API
- mini-swe-agent vs OpenAI Agents API
- MiniMax Code vs OpenAI Agents API
- Mistral Vibe CLI vs OpenAI Agents API
- Muse Code vs OpenAI Agents API
- OpenAI Agents API vs OpenAI Codex
- OpenAI Agents API vs OpenCode
- OpenAI Agents API vs OpenHands
- OpenAI Agents API vs OpenMausBot
- OpenAI Agents API vs Prime Agent
- OpenAI Agents API vs Qoder CLI
- OpenAI Agents API vs Qwen Code
- OpenAI Agents API vs Mirror CLI
- OpenAI Agents API vs Rovo Dev CLI
- OpenAI Agents API vs Unstoppable
- OpenAI Agents API vs Vibe-Trading
- OpenAI Agents API vs Warp (Warp Agent CLI and the Oz Agent API)
Machine-readable
- This page as Markdown
/compare/aider-vs-openai-agents-api.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/aider.json·/api/v1/tools/openai-agents-api.json - From a terminal
anchor compare aider openai-agents-api(the CLI) - Over MCP
compare_tools {"a": "aider", "b": "openai-agents-api"}at/mcp, no key