cc-whatsnew

cc-whatsnew is a skill for Claude Code from iroha924/mumei. It costs 124 tokens per session (1,671 once invoked), scanned A, original, MIT.

A Claude Code changelog reader that fetches official release notes and explains what changed in selected versions.

In plain words
What is it for?
It helps review the latest release, a chosen version, a version range, or the last several versions, then assess relevance to mumei.
Why use it?
It removes the need to manually compare release notes or guess which new features apply to a particular setup.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions CLAUDE.md; mentions subagents; names the AskUserQuestion tool.

Part of the mumei plugin — 11 skills, 10 agents, 18 hooks shipped together

Good fit It helps review the latest release, a chosen version, a version range, or the last several versions, then assess relevance to mumei.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/iroha924/mumei/cc-whatsnew
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 iroha924/mumei --skill cc-whatsnew
Clone the repo
git clone --depth 1 https://github.com/iroha924/mumei

Made for: Claude Code.

Or install mumei, the plugin that ships this one along with the rest of its 11 skills, 10 agents, 18 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 cc-whatsnew

README.md
[![agentmods](https://agentmods.dev/badge/skills/iroha924/mumei/cc-whatsnew/github.svg)](https://agentmods.dev/skills/iroha924/mumei/cc-whatsnew)
Your own site
<a href="https://agentmods.dev/skills/iroha924/mumei/cc-whatsnew"><img src="https://agentmods.dev/badge/skills/iroha924/mumei/cc-whatsnew/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 cc-whatsnew

Your own site · 80×15
<a href="https://agentmods.dev/skills/iroha924/mumei/cc-whatsnew"><img src="https://agentmods.dev/badge/skills/iroha924/mumei/cc-whatsnew.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 124 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,671 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.
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 $0.00124 $0.01671
Opus 5 $0.00062 $0.00835
Sonnet 5 $0.00025 $0.00334
Haiku 4.5 $0.00012 $0.00167

Measured 11d ago against content hash 1489e5ed41d1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

cc-whatsnew 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 11d 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.

.claude/skills/cc-whatsnew/SKILL.md · 197 lines

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.

cc-whatsnew

Fetches new Claude Code features from official sources and judges their applicability to mumei in one pass.

Step 1. Determine the scope

Interpret $ARGUMENTS with these rules:

Input example Interpretation
latest or empty release notes for the latest version
v2.1.139 / 2.1.139 single version
v2.1.135..v2.1.140 range (both ends inclusive)
last 5 / last 10 cumulative diff of the last N versions

If $ARGUMENTS is empty, choose the scope via AskUserQuestion. Question and options:

  • question: Which range of the Claude Code changelog should be fetched?
  • header: Range
  • options:
    1. Latest version — release notes for the most recent release
    2. Last 5 versions — cumulative diff
    3. Specific version — enter vX.Y.Z via Other
    4. Specify a range — enter vA..vB via Other

For "Specific version" and "Specify a range", use the Other input as-is.

Step 2. Fetch from primary sources

Fetch the original text with WebFetch from one of the following, always. Never report from memory-based guesses or search-result summaries alone:

  • https://github.com/anthropics/claude-code/releases — release page originals
  • https://code.claude.com/docs/en/changelog — official changelog

When a new field or new API appears, additionally fetch for spec confirmation:

  • https://code.claude.com/docs/en/hooks
  • https://code.claude.com/docs/en/skills
  • https://code.claude.com/docs/en/plugins-reference
  • https://code.claude.com/docs/en/commands
  • the feature's dedicated page (e.g. agent-view, model-config)

Read the full file on GitHub · 197 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. 11d ago First seen · 197 lines · 124 tokens per session scan A 1489e5ed41d1

Subscribe to this mod's changes

cc-whatsnew is a skill published in the GitHub repository iroha924/mumei (2 stars, last pushed 4d ago), licensed MIT. It adds 124 tokens to every session and 1,671 once invoked, about $0.0006 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.