breaking-changes-management

breaking-changes-management is a skill for Claude Code, Codex from PracticalSwan/agent-skills. It costs 43 tokens per session (1,017 once invoked), scanned A, original, MIT.

A guide for handling changes that can break existing users of an API, configuration, command, or file format. It covers versioning, migration instructions, deprecation notices, and changelog updates.

In plain words
What is it for?
It is for managing breaking changes, major releases, renamed or removed APIs, changed request or response formats, and upgrade documentation.
Why use it?
It helps users understand what changed, whether they are affected, and how to update their code or configuration. It also makes compatibility risks explicit before release.

Skill for Claude CodeCodex

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/practicalswan/agent-skills/breaking-changes-management
Any agent
npx skills add PracticalSwan/agent-skills --skill breaking-changes-management
Clone the repo
git clone --depth 1 https://github.com/PracticalSwan/agent-skills

Made for: Claude Code, Codex.

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 breaking-changes-management

README.md
[![agentmods](https://agentmods.dev/badge/skills/practicalswan/agent-skills/breaking-changes-management.svg)](https://agentmods.dev/skills/practicalswan/agent-skills/breaking-changes-management)
Your own site
<a href="https://agentmods.dev/skills/practicalswan/agent-skills/breaking-changes-management"><img src="https://agentmods.dev/badge/skills/practicalswan/agent-skills/breaking-changes-management.svg" alt="Measured on agentmods" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,017 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 $0.00043 $0.01017
Opus 5 $0.00022 $0.00508
Sonnet 5 $0.00009 $0.00203
Haiku 4.5 $0.00004 $0.00102

Measured yesterday against content hash 7c1e47169b51, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

breaking-changes-management 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.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/migration-guide-scaffold.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

breaking-changes-management/SKILL.md · 104 lines

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.

Breaking Changes Management

Use this skill when behavior, interfaces, configuration, or compatibility contracts change in a way that can break consumers.

  • Leverage native parallel subagent dispatch and 200k+ context windows where available.

Activation Conditions

Use symptom -> action triggers: when one matches, apply this skill and verify with the protocol below.

  • Releasing a major version
  • Renaming or removing public APIs
  • Changing request or response shapes
  • Replacing config keys, env vars, CLI flags, or file formats
  • Writing migration notes, deprecation notices, or upgrade checklists

Workflow

  1. Identify the exact consumer-visible break.
  2. State who is affected and from which version.
  3. Provide the replacement path or mitigation.
  4. Add before/after examples.
  5. Update CHANGELOG.md and any setup or usage docs that changed.

Required Outputs

  • Changelog entry with a clear BREAKING label
  • Migration guide with old usage, new usage, and upgrade steps
  • Deprecation timeline if removal is delayed
  • Validation notes for any examples or scripts that changed

Anti-Patterns

  • Starting work before the plan or gate is clear: Execution drifts when success criteria are implied instead of explicit.
  • Treating verification as optional cleanup: The last mile is where regressions and missing updates are usually hiding.
  • Mixing planning, implementation, and release work in one jump: You lose the causal chain that explains why a change is safe.

Verification Protocol

Before claiming "skill applied successfully":

  1. Pass/fail: The Breaking Changes Management workflow starts from explicit success criteria, constraints, and stop conditions.
  2. Pass/fail: Required evidence is collected before any completion, approval, or readiness claim.
  3. Pass/fail: The next action follows the documented gate order without skipping review or verification steps.
  4. Pressure-test scenario: Apply the workflow under time pressure with one failing check and one tempting shortcut.
  5. Success metric: Zero rationalizations; blocked, failed, or unverified work is reported as such.

Read the full file on GitHub · 104 lines

Files

What ships with it

4 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. yesterday Changed 7c1e47169b51
  2. 5d ago First seen · 104 lines · 43 tokens per session scan A e2eb0f09741f

Subscribe to this mod's changes

breaking-changes-management is a skill published in the GitHub repository PracticalSwan/agent-skills (13 stars, last pushed 4d ago), licensed MIT. It adds 43 tokens to every session and 1,017 once invoked, about $0.0002 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.