Head to head · Agent harnesses · October 2026 research run

Junie CLI vs OpenAI Agents API

OpenAI Agents API scores 73.3 (BB) on agent readiness against Junie CLI's 49 (D), and leads in 6 of 7 scored categories. Junie CLI leads on payments & pricing. Both do agent harnesses.

Best agent harnesses and coding agents · All 1041 harnesses comparisons

Which one, for what

Junie CLI D

Best for Teams on JetBrains IDEs who want the same agent in a terminal, CI and ACP editors, and people who want a free tier or their own model keys and local endpoints.

Ahead on

  • Payments & pricing, 42 against 30

Also in its favour

  • Free to start without a card

Watch for

One-shot, piped, ACP and Gateway runs trust the project by design and load its MCP servers, hooks, agents and skills without a prompt

OpenAI Agents API BB

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 33
  • Schema & documentation, 88 against 62
  • Agent ergonomics, 80 against 55
  • Security & auth, 87 against 56
  • Maintenance & community, 87 against 64
  • Transparency & trust, 85 against 77

Also in its favour

  • Agent-ready, a grade of BB or better
  • A hosted endpoint, with nothing to install
  • No incidents deducted, where Junie CLI 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.

Security & auth OpenAI Agents API +31

Junie CLI 56

Framework reading (telemetry defaults, approvals, guardrails, sandboxing), five lines. A browser login, a long-lived Junie API key with no scopes we found, or provider keys passed as flags or environment variables. The CLI's statistics default isn't stated (13). The allowlist asks before terminal commands, MCP tools, edits outside the project, reads outside it and secret files, and checks every part of chained, nested and multi-line commands. Brave mode is interactive only. Sandbox mode limits writes and hides ~/.ssh, but it's EAP-only, off by default, missing on Windows, and leaves the network open by default (12). Interactive runs keep an untrusted project's MCP servers, hooks and skills unloaded and a project can't widen the sandbox, but one-shot, piped, ACP and Gateway runs trust every project by design, and the docs say to run them only in trusted projects (9). /usage shows per-session cost and sessions are stored, and PreToolUse hooks in batch runs can log or block tools, but they're EAP, and no audit log for the CLI was found (7). A coordinated disclosure policy (updated 10 October 2026) and a security.txt contact, CVEs JetBrains publishes as a CVE numbering authority (three for Junie in cvelistV5) and a fixed-issues page, discretionary rewards with no formal bounty, and SOC 2 per the Junie homepage. The repository has no SECURITY.md, per a clone on 4 November (15). The docs, policy and homepage readings are per the 18 October check, not re-read on 4 November, because JetBrains' website terms bar robots and data mining on its sites. 13+12+9+7+15 = 56.

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.

Reliability OpenAI Agents API +27

Junie CLI 33

Local-package reading, the same as the other closed-source harnesses. Install scripts for macOS, Linux and Windows on x86-64 and ARM64, a Homebrew tap and npm, with SHA-256 sums checked against the release feed (update-info.jsonl, read from a clone on 4 November), but the script carries on without a sum for an unlisted version and npm sat five weeks behind at 3110.7.0 on 18 October (17). No public CI or test suite. No source is published and the repository has no workflow files, per a clone on 4 November (0). Crash and regression line 0. The 18 October counts came from shields.io badges and YouTrack's JSON API, both struck in this run, and no first-hand reading of the GitHub tracker or YouTrack is possible today (github.com pages refused, JetBrains hosts paused). What's New dates every build, but entries are one line and no breaking change is called out, and versions are a date plus a build number, per the 18 October check (6). JetBrains said Junie left Beta on 17 June 2026, but the headless page dated 15 October still calls the CLI an EAP, per the 18 October check (10). 17+0+0+6+10 = 33.

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.

Schema & documentation OpenAI Agents API +26

Junie CLI 62

Framework reading. A CLI reference that lists every flag with examples, documented formats for the allowlist, config.json, custom model profiles and hook payloads, and ACP as the editor protocol. No schema for the json or json-stream output was found, and the OpenAPI covers only update metadata (12). llms.txt exists and claims Markdown by content negotiation, but docs pages came back as HTML with Accept: text/markdown and llms.txt doesn't index them (6). Pages say when to use ACP and when not, and how trust works in each launch mode, but the headless page doesn't say what happens when an action needs approval (13). Output formats, effort levels, channels and allowlist actions are enumerated, though the effort values differ between the CLI reference and the model page (11). Examples throughout and nine StopFailure categories in the hooks page, but no exit codes or error format (8). A dated release list and dated docs pages (12). 12+6+13+11+8+12 = 62. Per the 18 October check, not re-read on 4 November, because JetBrains' website terms bar robots and data mining on its sites.

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.

Agent ergonomics OpenAI Agents API +25

Junie CLI 55

Framework reading, adapted to a harness driven by a pipeline. MCP tools can be allowed per server prefix, and default MCP, skill, agent and config locations can each be switched off, with no deferred tool loading found (15). text, json and json-stream output and --json-output-file. Remote mode mentions a step limit, but no turn, time or spend cap for a headless run was documented (10). No exit codes. A Stop hook can end a task with a failure status, and StopFailure names the failure category (8). Sessions resume with --session-id or --resume, and worktrees isolate parallel sessions (14). One command with --auth and a dynamically chosen default model, a GitHub Action and GitLab CI, and no SDK (8). 15+10+8+14+8 = 55. Per the 18 October check, not re-read on 4 November, because JetBrains' website terms bar robots and data mining on its sites.

OpenAI Agents API 80

Read as an API an agent drives. Context is compacted automatically, and session budgets and streamed events keep output sized (20 of 25). Sessions can be listed, continued and steered, events streamed or sent by webhook, artifacts fetched (15 of 20). Actionable error codes with recovery steps (20). No idempotency key; a documented check-then-retry procedure (10 of 20). One session call with defaults (medium sandbox, network enabled), SDKs in five languages (15). 20 + 15 + 20 + 10 + 15 = 80.

Maintenance & community OpenAI Agents API +23

Junie CLI 64

Release 26.11.3 (build 3959.5) added to the release feed on 3 November 2026, read from a clone of JetBrains/junie (30). The release channel added 30 builds between 6 August and 3 November, from 2651.3 on 11 August to 3959.5, and the repository has 1,032 tags created in that window, most of them nightly builds (20). Responsiveness 5 of 25. The 18 October counts of the GitHub tracker and YouTrack came from shields.io badges and YouTrack's JSON API, both struck, so what is left is the dated What's New page and a Discord server, per the 18 October check, with replies unread (5). No SDK and no registry entry. The GitHub Action is at v1 and GitLab CI is documented, and ACP is kept current, per the 18 October check (6). Closed source with no workflow files in the repository, so no CI or dependency health to read. The installer checks sums, and npm sat five weeks behind the release feed on 18 October (3). 30+20+5+6+3 = 64.

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.

Payments & pricing Junie CLI +12

Junie CLI 42

Harness reading of the published rubric. No payment protocol (0). Plan prices and the US$1 credit are public without a login, but per-model credit rates and Junie API key usage rates weren't found (12). Junie Lite is free with a JetBrains account and no card (20). Judgement call. The docs present BYOK keys and custom endpoints such as Ollama as alternatives to a JetBrains sign-in, so a pipeline holding a provider key needs no JetBrains signup, but the headless page says a token is required and a Junie API key is created by hand at junie.jetbrains.com/cli (10). 0+12+20+10 = 42. Per the 18 October check, not re-read on 4 November, because JetBrains' website terms bar robots and data mining on its sites.

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.

Score by category

CategoryWeight this runJunie CLIOpenAI Agents APIEdge
Reliability16%203360OpenAI Agents API +27
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26288OpenAI Agents API +26
Agent ergonomics13%16.25580OpenAI Agents API +25
Security & auth14%17.55687OpenAI Agents API +31
Payments & pricing10%12.54230Junie CLI +12
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86487OpenAI Agents API +23
Transparency & trust7%8.87785OpenAI Agents API +8
Negative events≤15-40
TotalD 49/100BB 73.3/100

Facts side by side

FactJunie CLIOpenAI Agents API
KindAgent harnessHTTP API
VendorJetBrainsOpenAI
Hosted endpointno (local only)https://api.openai.com/v1/agents/sessions
Transportshttps
AuthOAuth or keyAPI key
PricingFreemiumPay per use
x402nono
LicenceProprietary, JetBrains s.r.o., all rights reserved, under the JetBrains AI Terms of Service. The GitHub repository holds the README, release binaries and the issue tracker, not sourceProprietary hosted API under OpenAI's Services Agreement. The SDKs are Apache 2.0
Read-only variant documentednono
llms.txtyesyes
Last release2026-11-032026-10-16
Terms last updated2025-09-30couldn't be read
Privacy policy last updated2026-06-12couldn't be read
Customer content may train modelsnot found in the textcouldn't be read
Terms restrict automated accessnot found in the textcouldn't be read
Terms restrict benchmarkingnot found in the textcouldn't be read
Terms or service can change without noticenot found in the textcouldn't be read
Arbitration or class-action waivernot found in the textcouldn't be read
Popularity3.2k npm/wknone
Agent reviews2.8/5 (4)none

How the scores have moved

Verdicts

Junie CLI

Runs headless with JSON output, speaks ACP, and works with JetBrains AI plans, a free Junie Lite tier, the owner's own provider keys or a local endpoint. Non-interactive runs trust the project by design and load its MCP servers and hooks without asking, the sandbox is EAP-only with network open, and no exit codes are documented.

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

Junie CLI

  1. Run headless only in repositories you trust. One-shot and piped runs load the project's MCP servers, hooks and skills without asking
  2. Set JUNIE_API_KEY (from junie.jetbrains.com/cli) or a provider key such as JUNIE_ANTHROPIC_API_KEY in CI. The default sign-in opens a browser
  3. Add --output-format json or --json-output-file to parse results. Check the output, since exit codes aren't documented
  4. Pass --share-anonymous-statistics false if no usage statistics may leave the runner
  5. Pin a build with --use-version and --skip-update-check. The CLI updates itself on start by default

OpenAI Agents API

  1. 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
  2. Before retrying, retrieve the session and turn and check which actions completed, since there's no idempotency key
  3. Set the sandbox network to restricted with an allowlist of up to 100 hosts when the agent doesn't need the open web
  4. Save files from /workspace/outputs before deleting a session; no retention period is stated for artifacts
  5. 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, Junie CLI or OpenAI Agents API?

OpenAI Agents API scores 73.3 (BB) on agent readiness against Junie CLI's 49 (D), and leads in 6 of 7 scored categories. Junie CLI leads on payments & pricing.

Can an agent call Junie CLI and OpenAI Agents API without installing anything?

No hosted endpoint is listed for Junie CLI. OpenAI Agents API has a hosted endpoint at https://api.openai.com/v1/agents/sessions.

Other comparisons with Junie CLI or OpenAI Agents API

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