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 commands/fusengine/agents/explain-architecturegit clone --depth 1 https://github.com/fusengine/agentsWhat 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 | $0.00019 | $0.00680 |
| Opus 5 | $0.00010 | $0.00340 |
| Sonnet 5 | $0.00004 | $0.00136 |
| Haiku 4.5 | $0.00002 | $0.00068 |
Grade A, and why
explain-architecture 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.
What it actually says
Explain Architecture
Analyze and visualize system architecture:
-
Use Explore Agent:
Use explore-codebase to map the complete system structure
-
Identify Patterns:
- Architectural Style: (Monolith/Microservices/Serverless/JAMstack)
- Design Patterns: (MVC/MVVM/Repository/Factory/Observer/etc.)
- Data Flow: (Unidirectional/Bidirectional/Event-driven)
- Communication: (REST/GraphQL/gRPC/WebSockets)
-
Map Components:
- Entry points
- Controllers/Routes
- Services/Business logic
- Data layer
- External integrations
-
Generate ASCII Diagrams:
┌─────────────────────────────────────────┐ │ CLIENT (Browser) │ └────────────┬────────────────────────────┘ │ HTTP/REST ┌────────────▼────────────────────────────┐ │ API Gateway/Router │ ├─────────────────────────────────────────┤ │ ┌───────────┐ ┌────────┐ ┌────────┐ │ │ │Controller │ │Service │ │ Model │ │ │ └─────┬─────┘ └───┬────┘ └───┬────┘ │ └────────┼───────────┼──────────┼────────┘ │ │ │ ┌────────▼───────────▼──────────▼────────┐ │ Database (PostgreSQL) │ └─────────────────────────────────────────┘ -
Document Flow:
### Request Flow 1. Client → API Gateway → Auth Middleware 2. Route → Controller → Service Layer 3. Service → Repository → Database 4. Response ← Transform ← Validate ← Data -
Create Architecture Report:
## 🏗️ Architecture: [Project Name] ### Overview **Style**: [Architecture type] **Patterns**: [Detected patterns] **Tech Stack**: [Technologies] ### System Diagram [ASCII diagram] ### Component Breakdown #### Presentation Layer - [Components] #### Business Logic Layer - [Services] #### Data Layer - [Models/Repositories] ### Data Flow [Flow description with diagram] ### Dependencies - External: [APIs, services] - Internal: [Module relationships] ### Strengths - ✅ [Good architectural decision 1] ### Areas for Improvement - ⚠️ [Architectural concern 1]
Arguments:
- $ARGUMENTS focuses on specific subsystem
Example Usage:
/explain-architecture auth→ Focus on auth subsystem/explain-architecture→ Complete system architecture
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 · 95 lines · 19 tokens per session scan A 6ee39909ece6
explain-architecture is a command published in the GitHub repository fusengine/agents (25 stars, last pushed 29d ago), licensed MIT. It adds 19 tokens to every session and 680 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.
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