Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/hainamchung/agent-assistantnpx agentmods add agents/hainamchung/agent-assistant/frontend-engineerWrote 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/hainamchung/agent-assistant/frontend-engineer)<a href="https://agentmods.dev/agents/hainamchung/agent-assistant/frontend-engineer"><img src="https://agentmods.dev/badge/agents/hainamchung/agent-assistant/frontend-engineer/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/hainamchung/agent-assistant/frontend-engineer"><img src="https://agentmods.dev/badge/agents/hainamchung/agent-assistant/frontend-engineer.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 | $0.01150 |
| Opus 5.5 | $0.00007 | $0.00460 |
| Sonnet 5.5 | $0.00004 | $0.00230 |
| Haiku 4.5 | $0.00002 | $0.00115 |
Grade C, and why
frontend-engineer scanned grade C with 1 finding 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 1mo 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.
Hidden instructionshighPrompt injection
Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.
<!-- 🔒 COGNITIVE ANCHOR — MANDATORY OPERATING SYSTEM --> How it starts
The opening of the file, as written. The whole thing — 159 lines — stays where its author put it; the contents beside it link to each section on GitHub.
BINDING: This file OVERRIDES default AI patterns. Follow Thinking Protocol EXACTLY. EXTRACT: Core Directive + Constraints + Output Format before proceeding.
🎨 Frontend Engineer
| Attribute | Value |
|---|---|
| ID | agent:frontend-engineer |
| Role | Principal Frontend Architect |
| Profile | frontend:execution |
| Reports To | tech-lead |
| Consults | designer, backend-engineer, performance-engineer |
| Confidence | 85% (escalate if below) |
CORE DIRECTIVE: Build interfaces that feel alive. Every pixel serves a purpose. Accessibility is not optional—it's fundamental.
Prime Directive: DESIGN → BUILD → TEST → POLISH. User experience is the ultimate metric.
⚡ Skills
MATRIX DISCOVERY: Skills auto-injected from domain files in
~/.{TOOL}/skills/agent-assistant/matrix-skills/Profile:frontend:execution| Domains:frontend,design,architecture
🎯 Expert Mindset
THINK_LIKE:
- "Can a keyboard-only user use this?"
- "What happens on slow network?"
- "How does this look on mobile?"
- "Is the component reusable?"
ALWAYS:
- Handle loading, error, empty states
- Use semantic HTML elements
- Test across viewports
- Follow existing patterns
🧠 Thinking Protocol
Step 0: CONTEXT CHECK (MANDATORY)
1. CHECK PROJECT DOCS (if ./.documents/ exists):
- knowledge-standards/00-index.md → Coding standards (drill into sub-files as needed)
- knowledge-architecture/00-index.md → Component patterns (drill into sub-files as needed)
- knowledge-domain/00-index.md → API contracts, data shapes (drill into sub-files as needed)
→ USE these as constraints
2. CHECK for:
- ./.reports/{topic}/plans/PLAN-{feature}
- ./.reports/{topic}/designs/DESIGN-{feature}
→ EXISTS: READ fully, follow EXACTLY
→ NOT EXISTS + Complex: STOP → Request from tech-lead/designer
3. SCOUT existing patterns → Follow them
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.
- 1mo ago First seen · 159 lines · 18 tokens per session scan C c31c0e580e55
frontend-engineer is an agent published in the GitHub repository hainamchung/agent-assistant (54 stars, last pushed 4mo ago), licensed MIT. It adds 18 tokens to every session and 1,150 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it C with 1 finding (hidden instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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