background-terminals

A procedure for running shell commands that continue in the background while other work proceeds. It is intended for development servers, file watchers, streaming builds, and similar long-running tasks.

In plain words
What is it for?
It helps start, monitor, and stop development servers, watchers, builds, migrations, and other non-interactive commands.
Why use it?
It avoids tying up the main terminal or making the agent wait for a process that needs to keep running.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/openpi-dev/openpi/background-terminals
Any agent
npx skills add openpi-dev/openpi --skill background-terminals
Clone the repo
git clone --depth 1 https://github.com/openpi-dev/openpi

Made for: Claude Code, Codex.

Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 292 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00038 $0.00292
Opus 5 $0.00019 $0.00146
Sonnet 5 $0.00008 $0.00058
Haiku 4.5 $0.00004 $0.00029

Measured 2d ago against content hash b872a26df974, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

background-terminals 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 2d 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.

skills/background-terminals/SKILL.md · 31 lines

What it actually says

Background Terminals

Use bg_start for long-running commands; use regular bash for quick commands.

Start

Call bg_start with:

  • command: shell command to run
  • title: short recognizable label
  • working_dir: project directory when different from the current directory
  • timeout_seconds: optional deadline for finite work such as builds, tests, or migrations; omit for servers and watchers

Background commands receive no stdin. Never use them for interactive prompts.

After starting, continue useful work instead of polling. The terminal sends one completion message when it exits or times out.

Inspect and stop

  • Use bg_status only when current output or status is needed.
  • Use bg_list to inventory all tracked terminals.
  • Use bg_kill when a process is no longer needed or is stuck; termination continues even if the tool wait is aborted.
  • Tell the user they can open /ps to inspect live output and kill terminals interactively.

Prefer meaningful titles and avoid starting duplicate servers or watchers. Full output is captured to spill files; tool and completion output shows a concise tail. Terminals are session-scoped and are stopped during shutdown or reload.

Changes

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.

  1. 2d ago First seen · 31 lines · 38 tokens per session scan A b872a26df974

Subscribe to this mod's changes

background-terminals is a skill published in the GitHub repository openpi-dev/openpi (100 stars, last pushed 3d ago), licensed MIT. It adds 38 tokens to every session and 292 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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