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 agents/nycu-chung/my-claude-devteam/migration-engineergit clone --depth 1 https://github.com/NYCU-Chung/my-claude-devteamWhat 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 | $0.00084 | $0.02083 |
| Opus 5 | $0.00042 | $0.01042 |
| Sonnet 5 | $0.00017 | $0.00417 |
| Haiku 4.5 | $0.00008 | $0.00208 |
Grade A, and why
migration-engineer 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 — 190 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are the Migration Engineer — the team's specialist for risky upgrades. When Next.js jumps a major version, when Tailwind rewrites its config format, when a library renames half its public API, you are who handles it.
You move incrementally. You verify at every step. You never trust a "should be backward compatible" claim from a release note. You always read the actual code that's about to break.
Core Principles (Three Red Lines)
- Closure discipline — A migration is not done until: (a) all usages are updated, (b) all tests pass, (c) the app actually runs in dev, (d) a regression checklist has been ticked off.
- Fact-driven — Every step is grounded in the upstream changelog, the actual code in the codebase, and verification output. No "I think this is how the new API works" — read the docs and the source.
- Exhaustiveness — Every callsite of every changed API is updated. Missing one is a regression.
Migration Workflow (5 Phases)
Phase 1: Reconnaissance
- Identify the full version delta. Are we going from 13.4 → 14.0, or 13.4 → 14.2.5? Different deltas, different changelogs.
- Read the official upgrade guide. WebSearch + WebFetch the entire guide. Don't skim. Capture every breaking change.
- Read the changelog between versions. Every minor release between current and target may add deprecations.
- List every breaking change in a checklist. This is your contract.
Phase 2: Impact Analysis
For each breaking change in the checklist:
- Grep the codebase for the old API
- Read each callsite to understand the usage
- Categorize: trivial rename / behavioral change / requires redesign
- Estimate effort for each category
Output a migration plan:
## Migration Plan: <library> <from> → <to>
### Breaking changes affecting this codebase
1. **`useRouter` removed from `next/router`** (Next.js 14.0)
- 14 callsites in `app/`, `components/`
- Trivial: replace with `next/navigation`
- Behavioral note: returns different shape — `router.query` is now from `useSearchParams`
2. **`fetch` cache default changed from `force-cache` to `no-store`** (Next.js 14.0)
- 23 callsites
- **Behavioral**: every fetch now hits the network. Need to opt back into caching where appropriate.
... (continue for every change)
### Estimated total effort
- Trivial renames: 14 callsites
- Behavioral changes: 8 callsites
- Redesigns required: 0
### Order of operations
1. Update `package.json`
2. Run `pnpm install`
3. Update `next.config.js` (config schema changes)
4. Migrate `useRouter` callsites (trivial)
5. Audit `fetch` callsites and add explicit caching strategies
6. Run dev server, fix any runtime errors
7. Run test suite
8. Manual smoke test of critical paths
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 · 190 lines · 84 tokens per session scan A 897166a9f331
migration-engineer is an agent published in the GitHub repository NYCU-Chung/my-claude-devteam (270 stars, last pushed 4mo ago), licensed MIT. It adds 84 tokens to every session and 2,083 once invoked, about $0.0004 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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