safe-migrations

safe-migrations is a skill for Claude Code, Codex from thiientv/godmode. It costs 83 tokens per session (504 once invoked), scanned A, original, MIT.

A method for changing APIs, data schemas, frameworks, dependencies, protocols, storage, or infrastructure while keeping existing users working during the transition.

In plain words
What is it for?
Use it to plan deprecations, dependency upgrades, data moves, contract changes, and infrastructure changes with baselines, coexistence, monitoring, and removal criteria.
Why use it?
It reduces the risk of breaking consumers or losing data during upgrades and migrations by defining compatibility, staged cutovers, validation, and rollback or forward-fix plans.

Skill for Claude CodeCodex

Part of the godmode plugin — 34 skills, 1 hook shipped together

Install

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.

agentmods
npx agentmods add skills/thiientv/godmode/safe-migrations
Any agent
npx skills add thiientv/godmode --skill safe-migrations
Clone the repo
git clone --depth 1 https://github.com/thiientv/godmode

Made for: Claude Code, Codex.

Or install godmode, the plugin that ships this one along with the rest of its 34 skills, 1 hook.

Wrote 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.

agentmods badge for safe-migrations

README.md
[![agentmods](https://agentmods.dev/badge/skills/thiientv/godmode/safe-migrations.svg)](https://agentmods.dev/skills/thiientv/godmode/safe-migrations)
Your own site
<a href="https://agentmods.dev/skills/thiientv/godmode/safe-migrations"><img src="https://agentmods.dev/badge/skills/thiientv/godmode/safe-migrations.svg" alt="Measured on agentmods" height="20"></a>
Per session 83 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 504 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00083 $0.00504
Opus 5 $0.00042 $0.00252
Sonnet 5 $0.00017 $0.00101
Haiku 4.5 $0.00008 $0.00050

Measured 5d ago against content hash 775bd0ef1218, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

safe-migrations 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 5d 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.

skills/safe-migrations/SKILL.md · 61 lines

How it starts

The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Safe Migrations

Treat compatibility, state, and reversibility as first-class requirements.

Decide whether to migrate

Identify the forcing function, affected producers and consumers, stored state, support window, blast radius, and cost of leaving the old path in place. Reject a migration whose benefit does not justify its operational risk.

Establish the baseline

Before changing implementation, capture current contracts and representative behavior: tests, state snapshots, traffic shape, performance, error semantics, and rollback prerequisites. Existing consumers are part of the contract even when their behavior is undocumented.

Design coexistence and cutover

Choose a pattern from migration-patterns.md: expand/contract, adapter, dual-read/write, shadow, strangler, or versioned contract. Define phases, ownership, observability, data reconciliation, entry and exit criteria, and the exact point of no return.

Prefer additive steps:

  1. Introduce the new shape or implementation without removing the old one.
  2. Backfill or translate state with idempotent, resumable operations.
  3. Validate old and new behavior side by side.
  4. Shift traffic or consumers in measured stages.
  5. Hold through a defined observation window.
  6. Remove compatibility code only after usage reaches the agreed threshold.

For each phase, define rollback when reversible and a forward-fix when rollback would corrupt or discard newer state. Never label an untested rollback as a rollback plan.

Verification

Prove old-state/new-code and, when relevant, new-state/old-code compatibility. Check idempotency, interruption recovery, reconciliation, mixed-version operation, and empty-plan/no-diff behavior. Pair production cutover with release-engineering and data modeling with database-design.

Completion condition

The migration has phase-specific evidence, measurable cutover and abort gates, an owned recovery path, and explicit cleanup criteria; no destructive removal occurs while supported consumers or unreconciled state remain.

Read the full file on GitHub · 61 lines

Files

What ships with it

2 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.

Changes

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.

  1. 5d ago First seen · 61 lines · 83 tokens per session scan A 775bd0ef1218

Subscribe to this mod's changes

safe-migrations is a skill published in the GitHub repository thiientv/godmode (93 stars, last pushed 9d ago), licensed MIT. It adds 83 tokens to every session and 504 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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