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.
git clone --depth 1 https://github.com/vinhnx/VTCodeWrote 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/agents/vinhnx/vtcode/background-demo)<a href="https://agentmods.dev/agents/vinhnx/vtcode/background-demo"><img src="https://agentmods.dev/badge/agents/vinhnx/vtcode/background-demo/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/agents/vinhnx/vtcode/background-demo"><img src="https://agentmods.dev/badge/agents/vinhnx/vtcode/background-demo.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00018 | $0.00208 |
| Opus 5.5 | $0.00007 | $0.00083 |
| Sonnet 5.5 | $0.00004 | $0.00042 |
| Haiku 4.5 | $0.00002 | $0.00021 |
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 13d 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
Background Agent Demo
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 exec_command 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 exec_command 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.
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.
- 13d ago Changed · +2 lines edfabe6cbe8a
- 21d ago Changed a43aae1a1a24
- 1mo ago First seen · 21 lines · 18 tokens per session scan A 7a004962511a
background-demo is an agent published in the GitHub repository vinhnx/VTCode (880 stars, last pushed today), licensed Apache-2.0. It adds 18 tokens to every session and 208 once invoked, about $0.0001 per session on Opus 5.5. 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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