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 skills add magnus919/agent-skills --skill migration-engineeringgit clone --depth 1 https://github.com/magnus919/agent-skillsWrote 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/skills/magnus919/agent-skills/migration-engineering)<a href="https://agentmods.dev/skills/magnus919/agent-skills/migration-engineering"><img src="https://agentmods.dev/badge/skills/magnus919/agent-skills/migration-engineering/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/skills/magnus919/agent-skills/migration-engineering"><img src="https://agentmods.dev/badge/skills/magnus919/agent-skills/migration-engineering.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00083 | $0.02486 |
| Opus 5 | $0.00042 | $0.01243 |
| Sonnet 5 | $0.00017 | $0.00497 |
| Haiku 4.5 | $0.00008 | $0.00249 |
Grade A, and why
migration-engineering 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 9d 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 — 197 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Migration Engineering
Plan and execute safe migrations across system boundaries. A migration is any change that moves data, schemas, interfaces, infrastructure, or services from a current state to a target state while preserving correctness, availability, and recoverability during the transition.
This skill owns the cross-system migration method — compatibility design, staging, reconciliation, cutover, recovery, and deprecation. It does not own the implementation details of any single technology or subsystem; those belong to specialist skills.
When to use
Load this skill when the task involves:
| Trigger | Example |
|---|---|
| A schema change that must not break existing readers or writers | "Add a non-nullable column to a high-traffic table with zero downtime" |
| A data migration between stores or representations | "Migrate user profiles from Postgres to a dedicated service with its own database" |
| An API version migration with a deprecation window | "Move consumers from v1 REST to v2 GraphQL over six months" |
| An infrastructure or service migration | "Shift a workload from self-hosted VMs to a managed platform across regions" |
| A cross-system change requiring dual-running and reconciliation | "Replace the legacy billing engine with a new one while keeping both in sync" |
| Planning cutover, rollback, or irreversible steps for a migration | "Define the recovery strategy for the warehouse schema migration" |
When not to use
- Single-technology quick fixes — if the change is confined to one system with no compatibility window, no dual-running, and no cross-system coordination, use the relevant specialist skill directly (e.g., data-engineering for a simple DDL change, api-design-and-evolution for a single-endpoint deprecation).
- Tool-specific how-to guides — this skill provides the method, not vendor-specific instructions. It does not prescribe one migration technology, one database engine, one API gateway, or one infrastructure platform.
- Migrations without a system boundary — in-place refactors, code rewrites that don't cross a data or interface boundary, or single-service configuration changes are not migration-engineering scope.
- Guaranteeing rollback — this skill does not claim rollback is always possible. Some migrations include steps that are irreversible; the method requires identifying those steps explicitly and planning acceptance, communication, and contingency rather than implying a false safety net.
What ships with it
13 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- evals/evals.json 16 KB
- README.md 5.6 KB
- references/compatibility-patterns.md 4.2 KB
- references/discovery-brief.md 12 KB
- references/migration-types.md 4.5 KB
- references/planning-fields.md 2.2 KB
- references/recovery-classification.md 5.1 KB
- references/service-extraction-patterns.md 10 KB
- templates/compatibility-matrix.md 1.6 KB
- templates/cutover-and-recovery-record.md 1.8 KB
- templates/migration-plan.md 2.8 KB
- templates/reconciliation-plan.md 1.5 KB
- templates/service-extraction-assessment.md 5.8 KB
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.
- 9d ago First seen · 197 lines · 83 tokens per session scan A 6cbc9cda44a5
migration-engineering is a skill published in the GitHub repository magnus919/agent-skills (76 stars, last pushed yesterday), licensed MIT. It adds 83 tokens to every session and 2,486 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 2026-09-03.
Other skills, from other repositories
technical-integrations
Hunt existing integration patterns and design vendor/framework-agnostic API, RFC, SDK, and integration plans for new external vendor integrations.
xurl-api-probing
Probe APIs directly and methodically before assuming the client or app layer is at fault.
routing
Version: 1.0 Autor: BACH System Datum: 2026-02-18 API-Key: Nicht erforderlich (OSRM public, Nominatim).
weather
Version: 1.0 Autor: BACH System Datum: 2026-02-18 API-Key: Nicht erforderlich (wttr.in).
mcp-builder
Guide for creating high-quality MCP (Model Context Protocol) servers that enable LLMs to interact with external services through well-designed tools. Use when building MCP servers to integrate external APIs or services, whether in Python (FastMCP) or Node/TypeScript (MCP SDK).
implement-fastapi-routes
The file docstring contains a description of the FastAPI routes we need to implement. Implement these routes.