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 agentmods add skills/bearlike/assistant/app-buildernpx skills add bearlike/Assistant --skill app-buildergit clone --depth 1 https://github.com/bearlike/AssistantWhat 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 | $0.00053 | $0.00547 |
| Opus 5 | $0.00026 | $0.00273 |
| Sonnet 5 | $0.00011 | $0.00109 |
| Haiku 4.5 | $0.00005 | $0.00055 |
Grade A, and why
app-builder 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.
How it starts
The opening of the file, as written. The whole thing — 56 lines — stays where its author put it; the contents beside it link to each section on GitHub.
app-builder
app-builder is a sub-agent — delegate to it via spawn_agent. Do not design the data model, write the frontend, or author pipelines yourself.
How to invoke
spawn_agent(
agent_type="app-builder",
task="<intent + workspace choice — see below>",
acceptance_criteria="app_ready event emitted",
)
What goes in the task
The sub-agent designs the collections, frontend, and pipelines itself. It handles both live/render apps and periodic/collection-backed apps. Worked pipeline shapes live at ${CLAUDE_PLUGIN_ROOT}/examples/recipes/.
Your task gives it only two things:
- Intent — what the user wants the app to do, in their own terms (what it tracks, who it's for, how often it should refresh).
- Workspace choice — which workspace the app's agents anchor to:
own(a fresh private workspace for this app) orshared(an existing one, named). This is the one structural decision the user makes at creation; pass it through, don't invent it.
# Correct — intent + workspace, no layout
task=(
"Build an app that organizes my inbox into actionable task groups every morning "
"and shows them on a dashboard. Workspace: own."
)
# Wrong — prescribing the data model or the UI
task=(
"Create two collections `emails` and `groups`, a cron pipeline, and a Streamlit "
"page with a sidebar and three tabs..."
)
Do not prescribe collection schemas, the frontend layout, page structure, or pipeline mechanics. The sub-agent owns those decisions — prescribing them fights its judgment and produces a worse app.
After the sub-agent finishes
The app is live the moment app_ready fires. Reply with one sentence — "Done, your app is live." Don't describe what it shows; the user can open it.
What NOT to do
- Do not write frontend code, collection schemas, or pipeline prompts yourself.
- Do not call
activate_skill("app-builder")— that does nothing; usespawn_agent. - Do not describe the app's layout or data model in the task — hand off intent and let the sub-agent design it.
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.
- 2d ago First seen · 56 lines · 53 tokens per session scan A b57eee86d033
app-builder is a skill published in the GitHub repository bearlike/Assistant (41 stars, last pushed 8d ago), licensed MIT. It adds 53 tokens to every session and 547 once invoked, about $0.0003 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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