Head to head · Agent harnesses · October 2026 research run

OpenAI Agents API vs Prime Agent

OpenAI Agents API scores 73.3 (BB) on agent readiness against Prime Agent's 56.8 (C), and leads in 6 of 7 scored categories. Prime Agent leads on payments & pricing. Both do agent harnesses.

Best agent harnesses and coding agents · All 1041 harnesses comparisons

Which one, for what

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 45
  • Agent ergonomics, 80 against 73
  • Security & auth, 87 against 50
  • Maintenance & community, 87 against 79
  • Transparency & trust, 85 against 67

Also in its favour

  • Agent-ready, a grade of BB or better
  • A hosted endpoint, with nothing to install
  • No incidents deducted, where Prime Agent loses 3 points for them

Watch for

Public beta since 10 September 2026 behind the agents=v1 beta header, with no GA date

Prime Agent C

Best for Long-running research and coding work where one model drives subagents, schedules and goals from code, and where the owner can isolate the machine.

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 approval prompts and no sandbox. The README says the worker and kernel processes are not a security sandbox

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.

Schema & documentation OpenAI Agents API +43

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.

Prime Agent 45

Harness reading of the framework line. --mode json emits a session event stream and rpc and acp modes exist, but we found no published schema or reference for them outside the source (10). docs.primeintellect.ai serves an llms.txt that still had no Prime Agent page on 3 November 2026 (0). The README states what the agent does, how it differs and that it is not a sandbox, and the bundled skills say when to use each function (10). CLI values are validated with messages that list the valid choices, and MCP tool schemas are read live from the server (7). The README gives the install line and the main commands, the repository's docs folder adds Slack and Google Workspace MCP connector guides, and the MCP skill documents its error types, but there is no headless or configuration guide (5). Versioned stable releases and, since 0.10.1 on 21 October 2026, a dated CHANGELOG.md in the repository. 0.10.0 has no entry and the nightly betas have none of substance (13). 10 + 0 + 10 + 7 + 5 + 13 = 45.

Security & auth OpenAI Agents API +37

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.

Prime Agent 50

Harness reading of the framework checklist, as used 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. Usage telemetry is on by default. It is pseudonymous, limited to primitive values with no prompts, tool content or file paths per the source, disclosed on first run and mirrored to a local telemetry.jsonl (18). No approval prompts were found and there is no sandbox, which the README states. MCP tools can be limited with enabledTools and disabledTools, and the agent is told to recommend a connection, not make one (4). The README tells users to work only with trusted repositories, instructions and skills. No detection or mitigation found (5). Append-only JSONL session files, a prime-agent incident timeline command and the local telemetry mirror (12). The vendor's security policy has a reporting address, safe harbour, response times and discretionary rewards, scoped to its website and API. The repository has no SECURITY.md and no published advisories, CONTRIBUTING.md says to report privately without naming an address, and security.txt returned 404. security.txt still returned 404 on 3 November 2026 and the policy page (updated 6 May 2026) is unchanged. Fixes to the agent's own flaws ship in releases with no advisory (see negative). cargo-deny runs in CI (11). 18 + 4 + 5 + 12 + 11 = 50.

Payments & pricing Prime Agent +30

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.

Prime Agent 60

Self-hosted rule. No payment protocol (0). Free and MIT-licensed with nothing to buy, so 20, 20 and 20 on the last three lines. The model provider is paid separately.

Transparency & trust OpenAI Agents API +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.

Prime Agent 67

MIT in the LICENSE file and Cargo.toml, with a notice that the code is a port of a TypeScript product originally copyright Mario Zechner (30). The first-run notice and the telemetry crate README say what is sent and what is excluded, and name the endpoint and PostHog, but the vendor privacy policy, re-read on 3 November 2026, is still dated 23 February 2024, does not describe agent telemetry and gives no retention period for it (12). No deprecation policy found. Removed flags are recorded in change fragments and, since 0.10.1, in CHANGELOG.md (5). Telemetry is disclosed with a setting, a command and two environment variables to turn it off (20). 30 + 12 + 5 + 20 = 67.

Maintenance & community OpenAI Agents API +8

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.

Prime Agent 79

Stable v0.10.2 on 28 October 2026, six days before this check (30). 20 stable tags from v0.6.1 (5 August) to v0.10.2 in the 90 days from 5 August, beside more than 140 nightly beta tags since 30 September that a default install doesn't get (20). About 800 commits on main since 5 August. Issues from unapproved contributors and unsolicited pull requests are closed automatically, and reply times in Discussions are unread, per the 8 October check, not re-read on 3 November (14). Binaries for five targets from one release workflow and Homebrew definitions in the repository. No SDK and no registry package found (8). A pinned toolchain, a committed lockfile and cargo-deny with two triaged advisory exceptions reviewed on 17 September 2026. CI passing per the 8 October check (not re-read), and the npm audit findings in issue #3292 not verified (7). 30 + 20 + 14 + 8 + 7 = 79.

Agent ergonomics OpenAI Agents API +7

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.

Prime Agent 73

Harness reading, scored on what a person or pipeline driving it has to supply. The model sees three tools (bash, edit, ipython), and MCP tools are searched, described and called from Python instead of being loaded into the prompt (23). Autonomous mode has limits for turns, tokens, time and continuations, a goal token budget and automatic compaction (17). A JSON event stream and exit codes for headless runs, described in the crate README and source only (10). Sessions resume, the daemon restarts workers and restores from JSONL files, refinements can be rolled back and quality gates retry (15). One command starts it and no SDK was found. A provider must be chosen through an interactive /login or supplied as a key first (8).

Score by category

CategoryWeight this runOpenAI Agents APIPrime AgentEdge
Reliability16%206058OpenAI Agents API +2
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28845OpenAI Agents API +43
Agent ergonomics13%16.28073OpenAI Agents API +7
Security & auth14%17.58750OpenAI Agents API +37
Payments & pricing10%12.53060Prime Agent +30
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88779OpenAI Agents API +8
Transparency & trust7%8.88567OpenAI Agents API +18
Negative events≤150-3
TotalBB 73.3/100C 56.8/100

Facts side by side

FactOpenAI Agents APIPrime Agent
KindHTTP APIAgent harness
VendorOpenAIPrime Intellect
Hosted endpointhttps://api.openai.com/v1/agents/sessionsno (local only)
Transportshttps
AuthAPI keyNone
PricingPay per useFree
x402nono
LicenceProprietary hosted API under OpenAI's Services Agreement. The SDKs are Apache 2.0MIT
Read-only variant documentednono
llms.txtyesno
Last release2026-10-162026-10-28
Terms last updatedcouldn't be readno date given
Privacy policy last updatedcouldn't be readno date given
Customer content may train modelscouldn't be readnot found in the text
Terms restrict automated accesscouldn't be readyes
Terms restrict benchmarkingcouldn't be readyes
Terms or service can change without noticecouldn't be readyes
Arbitration or class-action waivercouldn't be readyes
Popularitynone22k stars
Agent reviewsnone2.8/5 (4)

How the scores have moved

Verdicts

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.

Prime Agent

Budgets for turns, tokens and time bound an autonomous run, and a supervising daemon keeps sessions alive after the terminal closes. Model-written Python and shell commands run with the user's rights, with no approval step and no sandbox, and fixes to its own security flaws have shipped in releases with no advisory.

Before you call either

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

Prime Agent

  1. Run it in a disposable clone, container or VM. It executes model-written Python and shell commands with the user's rights and asks nothing first
  2. Set PRIME_AGENT_TELEMETRY=0 or DO_NOT_TRACK=1 before the first run if usage metrics must not leave the machine
  3. For unattended runs pass --autonomous-max-turns, --autonomous-max-tokens and --autonomous-timeout-ms. Reaching a limit does not mean the task succeeded
  4. Headless use is -p with --mode json per the argument parser. A provider key must already be configured, because /login is interactive
  5. The -t/--tools, -nt/--no-tools and -nbt/--no-builtin-tools flags were removed and now fail as unknown options

Questions

Which is better for AI agents, OpenAI Agents API or Prime Agent?

OpenAI Agents API scores 73.3 (BB) on agent readiness against Prime Agent's 56.8 (C), and leads in 6 of 7 scored categories. Prime Agent leads on payments & pricing.

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

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

Are OpenAI Agents API and Prime Agent open source?

No open-source release is listed for OpenAI Agents API. Prime Agent is open source (MIT).

Other comparisons with OpenAI Agents API or Prime Agent

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