LongHorizon-Harness is a computer-use harness that lets AI agents continue work across desktop applications and the command line for extended periods by planning, acting, verifying, checkpointing, and recovering. It is for users who need Claude Code, Codex, OpenCode, or DeepSeek Harness to make reliable progress on complex long-running workflows without training a new model. The catalogue entries provide skills for operating this execution loop.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add AMAP-ML/LongHorizon-Harness --skill migrate-osworld-agentgit clone --depth 1 https://github.com/AMAP-ML/LongHorizon-HarnessWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/amap-ml/longhorizon-harness/migrate-osworld-agent)<a href="https://agentmods.dev/skills/amap-ml/longhorizon-harness/migrate-osworld-agent"><img src="https://agentmods.dev/badge/skills/amap-ml/longhorizon-harness/migrate-osworld-agent/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/amap-ml/longhorizon-harness/migrate-osworld-agent"><img src="https://agentmods.dev/badge/skills/amap-ml/longhorizon-harness/migrate-osworld-agent.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00033 | $0.00495 |
| Opus 5 | $0.00016 | $0.00247 |
| Sonnet 5 | $0.00007 | $0.00099 |
| Haiku 4.5 | $0.00003 | $0.00049 |
Grade A, and why
migrate-osworld-agent scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
Migrate OSWorld Agent
Use this when adding an upstream OSWorld agent to this repo.
Workflow
- Read the upstream agent.
- Read local patterns before editing:
- use
scripts/python/run_multienv_claude.pyas the main runner reference - use
scripts/bash/run_multienv_claude.shas the shell entrypoint reference - if a similar local agent exists, use it only for interface shape
- if none exists, derive the interface from the runner and
DesktopEnv
- use
- Copy the agent into
mm_agents/with a clear, non-conflicting name. - Adapt only the repo-facing interfaces:
predict()return shape- action dict fields consumed by
DesktopEnv.step() ASK_USERturns and follow-up user responses- done/fail markers
- task current date
- platform, screen, provider, and password settings
- Add a matching multi-env Python runner under
scripts/python/run_multienv_<agent>.py.- start from the closest retained runner structure
- keep task loading, env recreation, checkpoint args, logs, and cleanup behavior
- remove provider/model checks that only apply to the source runner
- Add a small shell entrypoint under
scripts/bash/.- use
uv run
- use
- Keep unrelated agents, scripts, results, and local dirty files out of the change.
Verify
Run fast checks first.
- Compile the new Python files.
- Check shell syntax.
- Check staged diff for whitespace.
- Run local fake tests for:
- action parsing
ASK_USER- user response returning to the agent
- checkpoint argument parsing if touched
Then run one small real smoke test.
- Use the intended provider.
- Use a tiny step limit.
- Prefer public IP for cloud providers when the local machine cannot reach private IPs.
- Confirm the model call happens.
- Confirm at least one environment action executes.
- Confirm result files and trajectory are written.
- Confirm cloud resources are cleaned up.
Before opening a PR, stage only the migration files and re-run the fast checks.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 12d ago First seen · 58 lines · 33 tokens per session scan A 597ace848f61
migrate-osworld-agent is a skill published in the GitHub repository AMAP-ML/LongHorizon-Harness (1,492 stars, last pushed 22d ago), licensed MIT. It adds 33 tokens to every session and 495 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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