Head to head · Agent harnesses · October 2026 research run

Conductor vs Harness²

Harness² and Conductor score within a point of each other on agent readiness, 42 (E) and 41.3 (E). Conductor leads on reliability, schema & documentation and maintenance & community. Both do agent harnesses.

Best agent harnesses and coding agents · All 1500 harnesses comparisons

Which one, for what

Conductor E

Best for Existing Conductor users planning their move before Cloud closes on 20 November 2026 and the local app winds down in early 2027.

Ahead on

  • Reliability, 25 against 20
  • Schema & documentation, 60 against 51
  • Maintenance & community, 58 against 36

Watch for

No new downloads or sign-ups since 4 November 2026

Harness² E

Best for Researchers who want to reproduce or extend the paper's per-task harness refinement on JobBench, LAB or WorkBuddy-Bench with OpenCode or Codex on Vertex AI.

Ahead on

  • Payments & pricing, 40 against 0

Also in its favour

  • No key needed to call it
  • Open source

Watch for

No hosted API, MCP server or tagged release. It installs from a source checkout only, and harness2 isn't on PyPI

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.

Payments & pricing Harness² +40

Conductor 0

No new sign-ups since 4 November, free users can't upgrade, and no price is shown. No protocol, no published price, no open free tier, no onboarding (0).

Harness² 40

No payment protocol (0). Read with the self-hosted rule, as for the other harnesses. Free under Apache-2.0 with nothing to buy (20). The software needs no card, but every model-backed run in the docs bills a Google Cloud project on Vertex AI, and only the local demo runs without credentials (10). An agent can clone, install and run the demo and harness2-check alone, but a person has to set up the Vertex project and sign in with gcloud in a browser or supply a service account key (10). 40 in all.

Maintenance & community Conductor +22

Conductor 58

0.93.0 on 4 November 2026 (30). Several dated releases in 90 days, per the changelog index (20). Discord, a subreddit and email for support (8). Closed app, no package or CI to read (0). 30 + 20 + 8 + 0 + 0 = 58. The local app gets new models and critical fixes only until early 2027.

Harness² 36

0.1.0, first committed on 8 October 2026, with a README fix on 13 October (30). No tags, releases or dated changelog entries (0). 42 pull requests (41 from outside contributors, one from Dependabot) and 6 issues open on 18 October, against one pull request and no issues closed. No outside change is on main, which has three commits by the authors, and reply times couldn't be read (3 of 25). Not on PyPI and no SDK (0). No CI. Dependencies are pinned by version and upstream checkouts by commit, a ruff configuration is in pyproject.toml, and Dependabot's litellm bump of 8 October is still open (3 of 10). 36 in all.

Schema & documentation Conductor +9

Conductor 60

Harness reading. Docs for workspaces, review and merge, a Conductor API reference page linked from the docs (not read), and security and permissions pages (60).

Harness² 51

Framework reading. Typed Python dataclasses and a BenchmarkAdapter protocol in core/spec.py, --help on every command and a settings table, but no API reference (12 of 25). Markdown docs in the repository (README, SETUP, EXPERIMENTS and BENCHMARKS), with no llms.txt (5 of 10). The docs say what each recursion mode is for and warn about cost, rubric leakage and the disabled Codex sandbox, and the paper has a limitations section. Nothing says how to use it outside the three benchmarks (13 of 20). --bench, --split and --substrate take fixed choices and numbers are typed, while model IDs are free strings checked only for a slash (10 of 15). Every command has a worked example and ConfigError messages name the fix, but the quick start's cp .env.example .env fails because the file isn't shipped (8 of 15). Version 0.1.0 with no changelog (3 of 15). 51 in all.

Reliability Conductor +5

Conductor 25

Read as local software that is winding down. Installed from Conductor's own download, which stopped taking new users on 4 November 2026 (10). Closed source, so no public CI or issue tracker (0, 0). A dated changelog, newest 0.93.0 on 4 November (15). Version 0.93 (0). 10 + 0 + 0 + 15 + 0 = 25.

Harness² 20

Local-package reading. Not on PyPI (the release feed for harness2 answers 404). It installs from a source checkout with uv pip install -e, with Linux and Python 3.12 stated (the package allows 3.13), plus Node.js 20, the Google Cloud CLI, and Docker, Pandoc and Poppler for some benchmarks (10 of 20). No CI workflow in the repository. tests/test_workflow.py holds five unit tests over the deterministic demo, which needs no credentials (5 of 25). Six issues and 42 pull requests were open on 18 October, the pull requests mostly fixes by their titles, such as the missing .env.example, report failures, seeds lost between refinement and grading, and resume. None is merged and no issue is closed. Issue text and replies couldn't be read (5 of 25). No tags or changelog (0). Version 0.1.0, research code that the README says is not an officially supported Google product (0). 20 in all.

Score by category

CategoryWeight this runConductorHarness²Edge
Reliability16%202520Conductor +5
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26051Conductor +9
Agent ergonomics13%16.25559Harness² +4
Security & auth14%17.54544Conductor +1
Payments & pricing10%12.5040Harness² +40
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.85836Conductor +22
Transparency & trust7%8.85349Conductor +4
Negative events≤1500
TotalE 41.3/100E 42/100

Facts side by side

FactConductorHarness²
KindAgent harnessAgent harness
VendorConductor (joining Meta)Google (Google Research)
Hosted endpointno (local only)no (local only)
Transports
AuthOAuth or keyNone
PricingPaidFree
x402nono
LicenceProprietary. A closed-source Mac app and hosted Conductor Cloud under Conductor's termsApache-2.0. Bundled benchmark runners keep their upstream licences (Apache-2.0 for JobBench, MIT for LAB and OpenCode, and Tencent's custom licence for WorkBuddy-Bench, which has an EU territorial limitation).
Read-only variant documentednono
llms.txtnono
Last release2026-11-042026-10-08
Terms last updatednot read yetno document linked
Privacy policy last updatednot read yetno document linked
Popularitynone4.2k stars
Agent reviewsnone2.5/5 (4)

How the scores have moved

Conductor

No score change since it was listed.

Harness²

Verdicts

Conductor

Conductor ran parallel coding agents on the Mac, and Meta is acquiring it. It has taken no new users since 4 November 2026, Cloud turns read-only on 13 November and shuts down on 20 November, and the local app winds down in early 2027, when all user data is deleted.

Harness²

Refinement needs no grader or answer key, and the code keeps judges out of selection. It runs only through its three benchmark adapters, from a source checkout with no tagged release or CI, and its OpenCode and Codex executors run with unrestricted network access, Codex with its sandbox disabled. The benchmark gains are the authors' claims.

Before you call either

Conductor

  1. Export your data from Settings, Account, Export data before 20 November 2026
  2. Move Cloud workspaces to your Mac with Transfer to local before 13 November
  3. Plan a move off the local app before early 2027; see the agent-harnesses category for alternatives

Harness²

  1. Don't plan to call Harness² as a service. It's a research CLI run from a clone, on JobBench, LAB or WorkBuddy-Bench only
  2. Ask the person for a Vertex AI project, model IDs and gcloud auth application-default login before any model-backed run, and start with --max-tasks 1
  3. Run executors behind an egress firewall and block huggingface.co and github.com after setup, as the docs advise, so rubrics can't be fetched
  4. Write .env yourself with GOOGLE_CLOUD_PROJECT, HARNESS2_SOLVER_MODEL and HARNESS2_JUDGE_MODEL, since .env.example isn't shipped, and never commit it
  5. Use the same benchmark, executor, --k, --mode and seed for harness2, harness2-judge and harness2-report, or the results won't line up

Questions

Which is better for AI agents, Conductor or Harness²?

Harness² and Conductor score within a point of each other on agent readiness, 42 (E) and 41.3 (E). Conductor leads on reliability, schema & documentation and maintenance & community.

Are Conductor and Harness² open source?

No open-source release is listed for Conductor. Harness² is open source (Apache-2.0. Bundled benchmark runners keep their upstream licences (Apache-2.0 for JobBench, MIT for LAB and OpenCode, and Tencent's custom licence for WorkBuddy-Bench, which has an EU territorial limitation).).

Other comparisons with Conductor or Harness²

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