deprecation-and-migration

deprecation-and-migration is a skill for Claude Code from nexus-substrate/nexus-agents. It costs 68 tokens per session (1,832 once invoked), scanned A, original, MIT.

A guide for safely retiring old software interfaces and changing public names or settings. A deprecated feature is one kept temporarily for compatibility while users move to its replacement.

In plain words
What is it for?
Use it to plan API removals, renames, configuration or command-line option changes, and other migrations after checking replacements, release history, tests, and consumers.
Why use it?
It helps prevent breaking other code that still depends on the old interface.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions CLAUDE.md.

Part of the nexus-agents plugin — 33 skills, 16 agents, 1 hook shipped together

Good fit Use it to plan API removals, renames, configuration or command-line option changes, and other migrations after checking replacements, release history, tests, and consumers.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/nexus-substrate/nexus-agents/deprecation-and-migration
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.

Any agent
npx skills add nexus-substrate/nexus-agents --skill deprecation-and-migration
Clone the repo
git clone --depth 1 https://github.com/nexus-substrate/nexus-agents

Made for: Claude Code.

Or install nexus-agents, the plugin that ships this one along with the rest of its 33 skills, 16 agents, 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 deprecation-and-migration

README.md
[![agentmods](https://agentmods.dev/badge/skills/nexus-substrate/nexus-agents/deprecation-and-migration/github.svg)](https://agentmods.dev/skills/nexus-substrate/nexus-agents/deprecation-and-migration)
Your own site
<a href="https://agentmods.dev/skills/nexus-substrate/nexus-agents/deprecation-and-migration"><img src="https://agentmods.dev/badge/skills/nexus-substrate/nexus-agents/deprecation-and-migration/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.

agentmods 80×15 button for deprecation-and-migration

Your own site · 80×15
<a href="https://agentmods.dev/skills/nexus-substrate/nexus-agents/deprecation-and-migration"><img src="https://agentmods.dev/badge/skills/nexus-substrate/nexus-agents/deprecation-and-migration.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,832 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 3 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Prompt Injection · line 91
    Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.
    Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
  • medium Prompt Injection · line 96
    Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.
    Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
  • medium Excessive Agency · line 105
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
How audits are shown
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 5.1 $0.00068 $0.01832
Opus 5 $0.00034 $0.00916
Sonnet 5 $0.00014 $0.00366
Haiku 4.5 $0.00007 $0.00183

Measured 12d ago against content hash 1ac6be2ff1c4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

deprecation-and-migration 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 12d 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/deprecation-and-migration/SKILL.md · 134 lines

How it starts

The opening of the file, as written. The whole thing — 134 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Deprecation and Migration Skill

When to apply

  • Retiring @deprecated-marked APIs
  • Renaming public types, classes, or string-union members
  • Removing v-gated cleanup work
  • Splitting an over-large public API into focused modules
  • Sunsetting a config option, env var, or CLI flag

Skip when:

  • The deprecation marker is fresh (< 1 minor version of bake) — let consumers see the warning first
  • No replacement exists yet — implement the replacement first, deprecate the old, then migrate
  • The change is purely internal (no public-barrel exposure) — that's a refactor, not a migration

Pre-removal checklist (before opening the cleanup PR)

  • Bake duration: the @deprecated marker has been in at least one published release for ≥ 1 minor version. Multi-month bake is preferred for typed APIs.
  • Replacement is canonical: the replacement exists, has tests, and is the documented preferred path in CLAUDE.md / docs/.
  • Migration recipe drafted: a one-block diff showing the before/after for the most common consumer use case.
  • Reachability audited: grep -rn for the deprecated symbol outside the package; check src/exports/*.ts to know if it's truly public or internal-only.
  • Semver target picked: patch (internal-only or runtime-unchanged), minor (TypeScript-typed-only break), or major (runtime API break).

The four-step process

1. Inventory

List every surface touched by the removal — types, schemas, classes, function names, internal callers, public re-exports, test fixtures, doc references.

# Symbol reach
grep -rn "DeprecatedName" src/ --include="*.ts" | wc -l

# Public-barrel check
grep -rn "DeprecatedName" src/exports/*.ts src/index.ts

# Doc references
grep -rn "DeprecatedName" docs/ skills/

Read the full file on GitHub · 134 lines

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. 12d ago First seen · 134 lines · 68 tokens per session scan A 1ac6be2ff1c4

Subscribe to this mod's changes

deprecation-and-migration is a skill published in the GitHub repository nexus-substrate/nexus-agents (18 stars, last pushed yesterday), licensed MIT. It adds 68 tokens to every session and 1,832 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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