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/monkilabs/opencastle/decompositionnpx skills add monkilabs/opencastle --skill decompositiongit clone --depth 1 https://github.com/monkilabs/opencastleWhat 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 | $0.00062 | $0.00919 |
| Opus 5 | $0.00031 | $0.00460 |
| Sonnet 5 | $0.00012 | $0.00184 |
| Haiku 4.5 | $0.00006 | $0.00092 |
Grade A, and why
decomposition 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.
How it starts
The opening of the file, as written. The whole thing — 104 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Task Decomposition
Dependency Resolution
TaskB → TaskA = B depends on A (must finish first).
Topological sort: No-dep tasks → Phase 1. Tasks depending only on Phase N → Phase N+1. Same-phase tasks with no mutual deps run in parallel.
Cycle detection: If A → B → C → A, split one task into independent part + dependent part.
Graph: Plan:
E → C → A Phase 1: A, B (parallel)
D → B Phase 2: C, D (parallel)
F → C, D Phase 3: E, F (parallel)
Delegation Spec
For score 1-3, objective + files + criteria is sufficient. Full template:
## Delegation Spec: [Task Title]
**Tracker Issue:** TAS-XX — [Title]
**Complexity:** [score]/13 → [tier] tier
**Agent:** [Agent Name]
### Objective
1-3 sentences: what to build/change and why.
### Context
- Key files: [list]
- Related patterns: [file:line references]
- Prior phase output: [compacted summary if applicable]
- Relevant lessons: [LES-XXX from LESSONS-LEARNED.md]
### Constraints
- File partition: Only modify files under [paths]
- Do NOT modify: [explicit exclusions]
- Dependencies: Requires [TAS-XX] Done first
### Acceptance Criteria
- [ ] Criterion 1
### Expected Output
Files changed · Verification (lint/test/build) · AC status (✅/❌) · Discovered issues · Lessons applied
Read .opencastle/LESSONS-LEARNED.md before starting. Add lesson if you retry any approach.
Prompt Quality
| Quality | Example |
|---|---|
| Strong (score 2) | "TAS-42 — Fix token refresh. Users get 'Invalid token' after 30 min. JWT 1h expiry in libs/auth/src/server.ts. Fix refresh logic. Only libs/auth/. Run auth tests." |
| Strong (score 8) | Use Delegation Spec Template above (all sections). |
| Weak | "Fix the authentication bug." |
Delegation Mechanism
Need result immediately?
YES → Is dependency for next step?
YES → Sub-Agent (inline)
NO → Sub-Agent or Background (if large)
NO → Expected > 5 min?
YES → Background Agent
NO → Sub-Agent (sequential)
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.
- yesterday First seen · 104 lines · 62 tokens per session scan A d12c5ba1c782
decomposition is a skill published in the GitHub repository monkilabs/opencastle (61 stars, last pushed 3d ago), licensed MIT. It adds 62 tokens to every session and 919 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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