background-demo

A minimal demo subagent for testing a managed background process. A background process runs separately while the main task continues.

In plain words
What is it for?
Use it to launch the supplied demo background script once and confirm that the process starts.
Why use it?
It provides a repeatable way to check that background subprocesses and their scripts start correctly. It is intended for documentation and smoke tests, which are quick checks that basic behavior works.

Agent

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 agents/vinhnx/vtcode/background-demo
Clone the repo
git clone --depth 1 https://github.com/vinhnx/VTCode
Per session 18 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 203 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 $0.00018 $0.00203
Opus 5 $0.00009 $0.00102
Sonnet 5 $0.00004 $0.00041
Haiku 4.5 $0.00002 $0.00020

Measured yesterday against content hash 7a004962511a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

background-demo 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 yesterday.

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.

.vtcode/agents/background-demo.md · 21 lines

What it actually says

Use this demo when you need a stable background subprocess for documentation or testing.

You are already running inside the managed background subprocess.

Do not call spawn_background_subprocess, spawn_agent, or any search tool. Use unified_exec exactly once to start ./scripts/demo-background-subagent.sh from the workspace root as a detached background process. Do not wait for heartbeat output. Do not call unified_exec more than once. After the tool returns, reply with exactly one readiness line that includes the launched PID or a concise confirmation that the process started and ends with task complete., then stop.

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. yesterday First seen · 21 lines · 18 tokens per session scan A 7a004962511a

Subscribe to this mod's changes

background-demo is an agent published in the GitHub repository vinhnx/VTCode (825 stars, last pushed 2d ago), licensed Apache-2.0. It adds 18 tokens to every session and 203 once invoked, about $0.0001 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.