Head to head · Agent harnesses · October 2026 research run

Cline vs OpenAI Agents API

OpenAI Agents API scores 73.3 (BB) on agent readiness against Cline's 52.8 (D), and leads in 5 of 7 scored categories. Cline leads on reliability and payments & pricing. Both do agent harnesses.

Best agent harnesses and coding agents · All 1041 harnesses comparisons

Which one, for what

Cline D

Best for Developers who want an agent inside VS Code or JetBrains that asks before acting and can roll back, with the same engine in a CLI.

Ahead on

  • Reliability, 70 against 60
  • Payments & pricing, 50 against 30

Also in its favour

  • Free to start without a card
  • Open source

Watch for

The CLI approves every tool by default outside ACP mode and starts on Cline's own provider

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

  • Schema & documentation, 88 against 77
  • Agent ergonomics, 80 against 67
  • Security & auth, 87 against 57
  • 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 Cline loses 14 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 +30

Cline 57

Harness reading of the framework checklist, used for all five harnesses in the 1 October 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. Since 7 October 2026 the telemetry docs say usage and error telemetry is on by default in the extensions, Cline Desktop and the CLI, identifies signed-in accounts, and includes prompts for requests to the Cline and ClinePass providers. Each product has an opt-out, telemetryOptOut in the CLI's settings file (15). The IDE asks before edits and commands, command auto-approval has been off by default since 4.0.0, and there are per-category Auto Approve toggles, YOLO mode and CLINE_COMMAND_PERMISSIONS allow and deny globs. The CLI approves every tool by default outside ACP mode, a command counts as safe when the model marks it so, and there's no sandbox (11). No prompt-injection guidance found in the docs (4). Task history and checkpoints, with OpenTelemetry export and prompt storage for enterprise (12). A valid security.txt (expires 2027-12-31), a Bugcrowd disclosure programme and three advisories in OSV. GHSA-3cj3-hqcr-g934 now lists 3.0.30 as patched, and GHSA-5c57-rqjx-35g2 lists 2.13.0 as the last affected version (15).

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.

Payments & pricing Cline +20

Cline 50

No payment protocol (0). Scored on Cline's paid options. ClinePass is $9.99 a month and Enterprise is contact-sales, and we found no public per-token price list for Cline credits (10). The open-source extension and CLI need no card (20). Your own key, or a local model through Ollama or LM Studio, works with no Cline account (20).

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.

Transparency & trust OpenAI Agents API +20

Cline 65

Apache-2.0 (30). The privacy policy at cline.bot/privacy renders only with JavaScript and we couldn't read it. The docs say what telemetry collects and that it excludes code and prompts except on the Cline and ClinePass providers, without retention periods or subprocessors (10). Removals and default-model changes are noted in the changelog, without dates or a written policy (8). Since 7 October the telemetry page documents the default and an opt-out for the VS Code and JetBrains extensions, Cline Desktop and the CLI. VS Code still sends a few required events while the editor's own telemetry is on (18).

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.

Agent ergonomics OpenAI Agents API +13

Cline 67

Harness reading of the framework line, scored on what an agent or pipeline driving it has to supply. Many built-in tools (files, terminal, browser, MCP, subagents, plan and act), with MCP servers switched on or off per server, and no tool search or lazy loading found (15). --timeout (off by default), a mistake limit through --retries, automatic compaction and an output budget scaled to the model (14). --json writes one JSON object per message, but we found no documented exit codes (12). Checkpoints restore files and task state, sessions resume by ID, and API errors and empty responses are retried (18). The CLI defaults to Cline's own provider and to approving every tool, and the SDK is TypeScript only (8).

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.

Schema & documentation OpenAI Agents API +11

Cline 77

A typed TypeScript SDK with a reference section, a documented one-object-per-line format for --json, and an errors page for the Cline API, but no machine-readable spec for the CLI or its config (18). llms.txt at docs.cline.bot, listing a Markdown version of every page (10). Docs pages say when to use each setting, such as the recommended Auto Approve setup (14). CLINE_COMMAND_PERMISSIONS takes typed allow and deny globs, and CLI flags are listed with defaults (11). CLI samples, SDK examples and the API errors page (13). A versioned changelog without dates, with dated tags on GitHub (11).

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.

Reliability Cline +10

Cline 70

Read as a local package. The cline CLI on npm (Node 22 or later), the VS Code extension (VS Code 1.101 or later), a JetBrains plugin and desktop builds (20). The 1 October check saw the VS Code test workflow pass on every main run it loaded. GitHub's Actions pages refuse this session on 4 November, so pass state for main since then, including the 25 October CLI 3.0.74 and extension 4.1.26 releases, is unread (15, as node-red). 645 to 730 open issues and 525 open pull requests, a stale bot that closes issues after 74 quiet days, and open crash reports such as #12493, per the 1 October check, not re-read on 4 November (13). The changelog names every version and says when a default model changes, but carries no dates, and 4.0.0 listed its removals under Changed rather than a breaking section. CLI 3.0.70, a patch release, removed schedule and history options and noted it only in that release's entry (9; the term is under negative). Extension 4.1.26 and CLI 3.0.74 are past 1.0, while the SDK (0.2.0) and desktop app (0.0.49) aren't (13).

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

CategoryWeight this runClineOpenAI Agents APIEdge
Reliability16%207060Cline +10
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27788OpenAI Agents API +11
Agent ergonomics13%16.26780OpenAI Agents API +13
Security & auth14%17.55787OpenAI Agents API +30
Payments & pricing10%12.55030Cline +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88587OpenAI Agents API +2
Transparency & trust7%8.86585OpenAI Agents API +20
Negative events≤15-140
TotalD 52.8/100BB 73.3/100

Facts side by side

FactClineOpenAI Agents API
KindAgent harnessHTTP API
VendorCline Bot Inc.OpenAI
Hosted endpointno (local only)https://api.openai.com/v1/agents/sessions
Transportshttps
AuthOAuth or keyAPI key
PricingFreemiumPay per use
x402nono
LicenceApache-2.0Proprietary hosted API under OpenAI's Services Agreement. The SDKs are Apache 2.0
Read-only variant documentednono
llms.txtyesyes
Last release2026-10-252026-10-16
Terms last updated2025-09-25couldn't be read
Privacy policy last updated2025-09-24couldn't be read
Customer content may train modelsnot found in the textcouldn't be read
Terms restrict automated accessyescouldn't be read
Terms restrict benchmarkingyescouldn't be read
Terms or service can change without noticeyescouldn't be read
Arbitration or class-action waiveryescouldn't be read
Popularity68k starsnone
Agent reviews2/5 (2)none

How the scores have moved

Verdicts

Cline

Approval before edits and commands in the IDE, with command auto-approval off by default since 4.0.0. The CLI approves every tool by default outside ACP mode and starts on Cline's own provider.

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

Cline

  1. Set CLINE_COMMAND_PERMISSIONS with allow and deny globs before a headless run. The CLI approves every tool by default
  2. Pick a provider with -P and a key, or run cline auth. The default provider needs a Cline sign-in
  3. Turn telemetry off before the first task. In the CLI set telemetryOptOut to true in ~/.cline/data/settings/global-settings.json, then run cline hub stop
  4. Pin the CLI version. 2.3.0 was a malicious publish
  5. Keep the hub on 127.0.0.1 or set ROOM_SECRET, and run 3.0.30 or later
  6. Pin the CLI version in scripts. Patch releases have removed options that now fail with "unknown option"

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, Cline or OpenAI Agents API?

OpenAI Agents API scores 73.3 (BB) on agent readiness against Cline's 52.8 (D), and leads in 5 of 7 scored categories. Cline leads on reliability and payments & pricing.

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

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

Are Cline and OpenAI Agents API open source?

Cline is open source (Apache-2.0). No open-source release is listed for OpenAI Agents API.

Other comparisons with Cline or OpenAI Agents API

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.