openhands skill

OpenHands CLI

Delegate coding tasks to the OpenHands CLI via the terminal tool. OpenHands is model-agnostic: any LiteLLM-supported provider (OpenAI, Anthropic, OpenRouter, DeepSeek, Ollama, vLLM, etc.).

This skill is the headless-mode wrapper for batch / one-shot delegation. The interactive textual UI is not used from Hermes.

When to Use

• User wants a coding task delegated to OpenHands specifically.
• User wants a coding agent that can run on a non-Anthropic / non-OpenAI provider (DeepSeek, Qwen, Ollama, vLLM, Nous, etc.) — sibling skills claude-code and codex are tied to one vendor.
• Multi-step file edits + shell commands inside a workspace.

For Claude-native, prefer claude-code. For OpenAI-native, prefer codex. For Hermes-native subagents, use delegate_task.

Prerequisites

1. Install upstream (requires Python 3.12+ and uv):

terminal(command="uv tool install openhands --python 3.12")

Verify: openhands --version (currently OpenHands CLI 1.16.0 / SDK v1.21.0 at time of writing).

1. Pick a model and set env vars for --override-with-envs:

export LLM_MODEL=openrouter/openai/gpt-4o-mini       # or any LiteLLM slug
   export LLM_API_KEY=$OPENROUTER_API_KEY
   export LLM_BASE_URL=https://openrouter.ai/api/v1     # omit for native OpenAI

LLM_MODEL uses LiteLLM's full slug. When the provider is OpenRouter the slug is doubly-prefixed: openrouter// (e.g. openrouter/anthropic/claude-sonnet-4.5). For native Anthropic: anthropic/claude-sonnet-4-5. For native OpenAI: openai/gpt-4o-mini.

1. Suppress the startup banner so JSON output isn't preceded by ASCII art:

export OPENHANDS_SUPPRESS_BANNER=1

How to Run

Always invoke through the terminal tool. Always pass --headless --json --override-with-envs --exit-without-confirmation for automation.

One-shot task

terminal(
  command="OPENHANDS_SUPPRESS_BANNER=1 LLM_MODEL=openrouter/openai/gpt-4o-mini LLM_API_KEY=$OPENROUTER_API_KEY LLM_BASE_URL=https://openrouter.ai/api/v1 openhands --headless --json --override-with-envs --exit-without-confirmation -t 'Add error handling to all API calls in src/'",
  workdir="/path/to/project",
  timeout=600
)

Background for long tasks

terminal(command="<same as above>", workdir="/path/to/project", background=true, notify_on_complete=true)
process(action="poll", session_id="<id>")
process(action="log", session_id="<id>")

Resume a previous conversation

OpenHands prints Conversation ID: <32-hex> and a Hint: openhands --resume line at the end of each run. Use the dashed form to resume:

terminal(
  command="OPENHANDS_SUPPRESS_BANNER=1 LLM_MODEL=... openhands --headless --json --override-with-envs --exit-without-confirmation --resume <dashed-uuid> -t 'Now fix the bug you found'",
  workdir="/path/to/project"
)

Real Flag List

Verified against openhands --help (CLI 1.16.0). Anything not in this table is not a flag — pass it via env var or settings file.

There is no --model, --max-iterations, --workspace, --sandbox, --sandbox-type flag. Model is LLMMODEL. Workspace is the workdir you pass to the terminal tool. Sandbox / runtime is the RUNTIME and SANDBOXVOLUMES env vars.

JSON Event Schema

With --json --headless, OpenHands emits JSONL — one JSON object per line, plus a handful of non-JSON status lines (Initializing agent..., Agent is working, Agent finished, the final summary box, Goodbye!, Conversation ID:, Hint:). Filter for lines starting with {.

Top-level kind field discriminates events:

• MessageEvent — user / agent text turn. source is user or agent.
• ActionEvent — agent picked a tool. Read toolname (fileeditor, terminal, finish) and action.kind (FileEditorAction, TerminalAction, FinishAction).
• ObservationEvent — tool result. observation.is_error is the success flag. source is environment.
• FinishAction inside an ActionEvent carries the agent's final message in action.message.

The cli prints all stderr from LiteLLM/Authlib first — see Pitfalls. Parse only stdout, line by line, ignoring lines that don't start with {.

Pitfalls

• LiteLLM warnings on every invocation. The CLI prints bedrock-runtime and sagemaker-runtime warnings to stderr because botocore isn't installed. Plus an Authlib deprecation. These are noise, not failures. Pipe stderr to /dev/null or filter it out before showing the user.
• Banner spam. Without OPENHANDSSUPPRESSBANNER=1, every run starts with a multi-line +--+ ASCII box advertising the SDK. Always export it.
• --override-with-envs is mandatory for automation. Without it, OpenHands ignores LLMAPIKEY / LLMBASEURL / LLM_MODEL and falls back to ~/.openhands/settings.json. On a fresh install this file doesn't exist and the CLI hangs waiting for first-run setup.
• Model slug is LiteLLM's, not the provider's. openrouter/openai/gpt-4o-mini works; openai/gpt-4o-mini while pointed at OpenRouter does not. anthropic/claude-sonnet-4-5 (hyphen) is native Anthropic; openrouter/anthropic/claude-sonnet-4.5 (dot) is via OpenRouter. Get it wrong → cryptic LiteLLM 400.
• pip install openhands-ai is the wrong package. That's the legacy V0 SDK. The new CLI is uv tool install openhands --python 3.12. There is no maintained conda package.
• Resume ID format is fiddly. The CLI ends with Conversation ID: f46573d9cfdb45e492ca189bde40019b (no dashes) and then a Hint: openhands --resume f46573d9-cfdb-45e4-92ca-189bde40019b (with dashes). Use the dashed form.
• Headless ignores --llm-approve. If you pass it, you get an argparse error. Headless mode hardcodes always-approve.
• No Windows support upstream. The OpenHands docs require WSL on Windows. This skill is gated [linux, macos] accordingly.
• ~/.openhands/conversations// accumulates. Each run persists a trajectory. Clean it up if running batches.
• Heavy install (~200 packages). Use uv tool install (isolated venv) to avoid dependency conflicts with the active project.

Verification

terminal(
  command="OPENHANDS_SUPPRESS_BANNER=1 LLM_MODEL=openrouter/openai/gpt-4o-mini LLM_API_KEY=$OPENROUTER_API_KEY LLM_BASE_URL=https://openrouter.ai/api/v1 openhands --headless --json --override-with-envs --exit-without-confirmation -t 'Print the string OPENHANDS_OK to stdout via the terminal tool.'",
  workdir="~/.hermes/cache/scratch",
  timeout=120
)

If the JSONL stream ends with a FinishAction whose action.message mentions OPENHANDS_OK, the install is working.

Related

• OpenHands GitHub
• OpenHands CLI command reference
• Sibling skills: claude-code (Anthropic-only), codex (OpenAI-only), opencode (multi-provider via OpenCode), hermes-agent (Hermes subagents via delegate_task).