semver

semver is a skill for Claude Code, Codex from LenoSeibert/semver-plugin. It costs 58 tokens per session (544 once invoked), scanned A, original, MIT.

A reference for Semantic Versioning 2.0.0, a standard way to number software releases based on compatibility changes. It explains version validity, release increments, and pre-release ordering.

In plain words
What is it for?
It is for selecting the next major, minor, or patch version, validating version strings, and comparing pre-release versions.
Why use it?
It helps avoid choosing a version number that misrepresents whether an update breaks existing users or adds compatible functionality.

Skill for Claude CodeCodex

Part of the semver-plugin plugin — 4 skills, 3 hooks 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/lenoseibert/semver-plugin/semver
Any agent
npx skills add LenoSeibert/semver-plugin --skill semver
Clone the repo
git clone --depth 1 https://github.com/LenoSeibert/semver-plugin

Made for: Claude Code, Codex.

Or install semver-plugin, the plugin that ships this one along with the rest of its 4 skills, 3 hooks.

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 semver

README.md
[![agentmods](https://agentmods.dev/badge/skills/lenoseibert/semver-plugin/semver.svg)](https://agentmods.dev/skills/lenoseibert/semver-plugin/semver)
Your own site
<a href="https://agentmods.dev/skills/lenoseibert/semver-plugin/semver"><img src="https://agentmods.dev/badge/skills/lenoseibert/semver-plugin/semver.svg" alt="Measured on agentmods" height="20"></a>
Per session 58 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 544 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 $0.00058 $0.00544
Opus 5 $0.00029 $0.00272
Sonnet 5 $0.00012 $0.00109
Haiku 4.5 $0.00006 $0.00054

Measured 3d ago against content hash 2c7b54fc609f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

semver 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 3d 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/semver/SKILL.md · 55 lines

How it starts

The opening of the file, as written. The whole thing — 55 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Semantic Versioning 2.0.0

Use the declared public API—not commit-message labels, diff size, or perceived importance—as the compatibility boundary. Ask what the public API is only when the available code and documentation cannot establish it safely.

Choose a bump

For versions at or above 1.0.0, select the highest applicable change:

  1. MAJOR: any backward-incompatible public API change. Reset minor and patch.
  2. MINOR: backward-compatible public API functionality or a deprecation. It may include fixes. Reset patch.
  3. PATCH: backward-compatible correction of incorrect behavior only.
  4. No release: no released artifact changes.

For 0.y.z, explicitly state that SemVer defines the API as unstable and does not prescribe which component represents a breaking change. Follow the project's documented 0.x policy; if absent, recommend and label a convention instead of presenting it as a SemVer requirement.

Validate syntax

A normal version is X.Y.Z, with non-negative integers and no leading zeroes. Pre-release identifiers follow -, are dot-separated ASCII alphanumerics or hyphens, are non-empty, and numeric identifiers have no leading zeroes. Build identifiers follow +, obey the same character/empty rules, and may have leading zeroes.

Do not accept a leading v as strict SemVer syntax. Mention when an ecosystem treats it as a tag convention rather than part of the version.

Compare precedence

Compare major, minor, and patch numerically. A pre-release is below the same normal version. Compare pre-release identifiers left to right: numeric numerically, non-numeric lexically in ASCII, numeric below non-numeric, and a longer sequence above its equal prefix. Ignore build metadata entirely.

Release invariants

  • Declare a precise public API before claiming SemVer compliance.
  • Never alter the contents of an already released version.
  • 1.0.0 defines the stable public API.
  • Explain the compatibility evidence behind the recommendation.
  • Cite https://semver.org/ when the user requests a source.

Read the full file on GitHub · 55 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. 3d ago First seen · 55 lines · 58 tokens per session scan A 2c7b54fc609f

Subscribe to this mod's changes

semver is a skill published in the GitHub repository LenoSeibert/semver-plugin (1 stars, last pushed 1mo ago), licensed MIT. It adds 58 tokens to every session and 544 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 2026-08-31.

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