# OpenAI Agents API vs Unstoppable (slim)

> OpenAI Agents scores 73.3 (BB) to Unstoppable's 34.7 (F) for agent harnesses. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/openai-agents-api-vs-unstoppable.md (~6,450 tokens) · this version ~2,980 tokens · JSON https://www.anchorterminal.com/compare/openai-agents-api-vs-unstoppable.json · canonical https://www.anchorterminal.com/compare/openai-agents-api-vs-unstoppable
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-11-06
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OpenAI Agents API scores 73.3 (BB) on agent readiness against Unstoppable's 34.7 (F), and leads in 6 of 7 scored categories. Both do agent harnesses.

- OpenAI Agents API: BB 73.3, rank #99 of 1354 · https://www.anchorterminal.com/tools/openai-agents-api.min.md
- Unstoppable: F 34.7, rank #1249 of 1354 · https://www.anchorterminal.com/tools/unstoppable.min.md
- OpenAI Agents API, good 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 45; Schema & documentation, 88 against 30; Agent ergonomics, 80 against 5; Security & auth, 87 against 36; Maintenance & community, 87 against 58; Transparency & trust, 85 against 56. Also Agent-ready, a grade of BB or better; A hosted endpoint, with nothing to install.
- Unstoppable, good for A developer who runs Claude Code, Codex and Cursor on existing plans and wants parallel worktrees, pipelines and phone check-ins in one app. Also No key needed to call it; Free to start without a card.

| Category | OpenAI Agents API | Unstoppable |
| --- | --- | --- |
| Reliability (16%) | 60 | 45 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 88 | 30 |
| Agent ergonomics (13%) | 80 | 5 |
| Security & auth (14%) | 87 | 36 |
| Payments & pricing (10%) | 30 | 30 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 87 | 58 |
| Transparency & trust (7%) | 85 | 56 |

| Fact (where they differ) | OpenAI Agents API | Unstoppable |
| --- | --- | --- |
| Kind | HTTP API | Agent harness |
| Vendor | OpenAI | Unstoppable Domains, Inc. |
| Hosted endpoint | `https://api.openai.com/v1/agents/sessions` | no (local only) |
| Transports | https |  |
| Auth | API key | None |
| Pricing | Pay per use | Freemium |
| Licence | Proprietary hosted API under OpenAI's Services Agreement. The SDKs are Apache 2.0 | Proprietary, under Unstoppable Domains, Inc.'s Terms of Service. No source published |
| Last release | 2026-10-16 | 2026-10-23 |
| Terms last updated | couldn't be read | 2026-10-06 |
| Privacy policy last updated | couldn't be read | 2026-10-08 |
| Customer content may train models | couldn't be read | not found in the text |
| Terms restrict automated access | couldn't be read | not found in the text |
| Terms restrict benchmarking | couldn't be read | yes |
| Terms or service can change without notice | couldn't be read | not found in the text |
| Arbitration or class-action waiver | couldn't be read | yes |

Why the edge:
- Agent ergonomics, OpenAI Agents API +75: 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.); Unstoppable 5 (These lines measure an interface an agent calls, and Unstoppable has none, so context cost, output controls and retries score nothing. For the person, a usage limit shows choices to wait for the reset or continue on credits (2 of 20). Guest use with no account, a first-run page that imports Claude and Codex projects, and few required settings. No SDK (3 of 15). Total 5.)
- Schema & documentation, OpenAI Agents API +58: 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.); Unstoppable 30 (Graded on the interface an outside agent can use, which is none. No API, OpenAPI file, MCP server or documented command (0). unstoppable.ai/llms.txt lists the product, help and policy pages in Markdown (10). Twenty-two dated help articles explain for a person what each part does and when to use it, such as Code and Work modes and approval modes (5 of 20). No typed inputs an agent could call (0). Step-by-step examples for people and named error states such as usage limit reached and update failed, with no error responses for an agent (3 of 15). Numbered versions and a public dated changelog, which lists only four releases from 20 to 23 October 2026 (12 of 15). Total 30.)
- Security & auth, OpenAI Agents API +51: 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.); Unstoppable 36 (Harness reading of the framework checklist, as for the other harnesses. 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. Activity sharing is Off for every activity type by default and secrets are removed before upload, but the privacy policy also collects usage telemetry (feature use, session activity, token and spend metrics, diagnostics) with no opt-out stated, and updates download automatically by default (15 of 30). Ask and Accept edits modes with allow and deny rules by command, file write, MCP tool and network host, deny winning, and safety rules that block force-pushes and destructive deletes. Every kind of chat starts in Full access, which skips prompts and safety rules, and local agents have no documented sandbox. Cloud worktrees get their own sandbox (8 of 20). The in-app browser stops agents acting on private sign-in pages. No other guidance on untrusted content from web pages, MCP servers or connected tools (3 of 15). Cost and usage panels, a team feed with tool-use metadata, approval rules with their origin, and an Audit Trail experiment in Labs (8 of 15). Two-factor authentication for accounts. No security.txt on unstoppable.ai, the parent's security.txt expired on 22 January 2024, its bug bounty policy link returns 404, and no SOC 2 or ISO 27001 found (2 of 20). Total 36.)
- Maintenance & community, OpenAI Agents API +29: 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.); Unstoppable 58 (Read for a closed product. Version 1.15.0 on 23 October 2026, and iOS 1.1.9 on 27 October (30). Four desktop releases from 20 to 23 October and nine iOS updates since 11 August 2026 (20). A public changelog, a support email, in-app feedback and a Discord server, none tested for replies. Help articles were updated between 19 and 24 October (6 of 15). No SDK and no MCP registry entry (0). Windows updates check signatures per the 1.13.0 notes, with no build pipeline to inspect (2 of 10). Total 58.)
- Transparency & trust, OpenAI Agents API +29: 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.); Unstoppable 56 (Closed source under terms of 6 October 2026 that name Unstoppable Domains, Inc. and Delaware law. The terms forbid reverse engineering and building a competing product (15). The privacy policy of 8 October 2026 is written for this product. It states activity sharing levels, Off by default, secret removal and encryption, and configurable transcript retention. It gives no retention periods, names no subprocessors, and says usage telemetry may sync depending on settings, which the site's 'we don't collect your code or conversations' leaves open (16 of 30). No deprecation policy. The terms allow removing parts of the service without notice. The changelog dates one retirement (GPT 5.5 to GPT 6.1 Sol) (3 of 20). No subprocessors or data locations disclosed, and the telemetry the app sends has no documented opt-out (6 of 20). Total 40.)
- Reliability, OpenAI Agents API +15: 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.); Unstoppable 45 (Read as local software, because the product is the desktop app the owner runs, as for the other harnesses. Signed downloads for macOS Apple Silicon, macOS Intel and Windows on the download page, version 1.15.0, plus iOS and Android apps in the stores, with the supported platforms stated. No package registry (20). Closed source with no public CI or test suite (0). No public issue tracker. Bugs go through in-app feedback, email and Discord, none of which shows a record we could read (0). Version numbers and a dated changelog, but only 1.12.0 to 1.15.0 are listed and breaking changes are not marked as such (10). Version 1.15.0 (15). The hosted parts (accounts, AI credits, cloud agents, Remote Control) have no status page. status.unstoppabledomains.com covers the domains business only.)