Sepia

Q: What is a Claude Code skill and how does the Sepia skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Sepia is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Content category. Learn more at https://claudskills.com/learn/what-is-skill-md/.

Category: Content · Sub-category: writing · Last updated: 2026-09-28

type:review type:debug

Make AI-generated writing read as human-written, in fiction and in professional prose. Repairs the narrative architecture of fiction and stories (based on StoryScope, arXiv:2604.03136); routes professional text through domain rules for release notes, announcements, PR and issue replies, code-review comments, incident postmortems, tickets, work orders, technical articles, blog posts, and long-form journalism. Four operations - write, review (diagnose AI tells without editing), refactor (minimal in-place edits), recreate (full rewrite). Use when asked to humanize, de-AI, unslop, or strip AI flavor from any text; when writing or revising any of these document types; or whenever output must not read as machine-written.

Security AStatic scan found no risk patternsHow grading works ›

From the source SKILL.md

This skill combines measured findings with marked editorial heuristics. In fiction, StoryScope's narrative-only classifier reached 93.2% macro-F1, while its Core Only 30-feature XGBoost held-out classifier reached 84.8% macro-F1 (AUPRC .828); the manual rubric is neither classifier. In professional prose the same structure-level result has been replicated once on company blog posts, where 187 structural features alone reached 98.0 macro-F1 on held-out companies (SLOPSHAPE-2026, a preprint with LLM-scored features and a pre-ChatGPT human corpus). The professional path combines measured studies…

What this skill does

Sepia is a community-contributed Claude Code skill in the writing sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/sepia/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use when asked to humanize, de-AI, unslop, or strip AI flavor from any text; when writing or revising any of these document types; or whenever output must not read as machine-written.

Who uses this skill

The Sepia Claude Code skill is built for content creators, marketers, copywriters, SEO professionals, and editorial teams. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 211,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/sepia
curl -L https://claudskills.com/skills/sepia/SKILL.md \
  -o ~/.claude/skills/sepia/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/sepia/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/sepia/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\sepia\SKILL.md on Windows. See the full install guide for step-by-step instructions.

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the Sepia Claude Code skill?

Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/sepia/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.

What does the Sepia skill do?

Is this skill free to install?

Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.

When should I use the Sepia skill?

Use Sepia when your Claude Code task falls under the Content category — specifically in the writing area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use Sepia" or describe the task and let Claude pick). Browse related skills at /category/content/.

What is a Claude Code skill and how does the Sepia skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Sepia is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Content category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Source: https://github.com/Nanako0129/sepia/blob/HEAD/skills/sepia/SKILL.md
License: MIT
Author: Nanako0129

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA

Nanako0129. (2026). Sepia [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/sepia/

BibTeX

@misc{sepia-2026,
  author    = {Nanako0129},
  title     = {Sepia [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/sepia/}
}

Embed this skill

Promote, attribute, or link this skill from your own README, blog post, or documentation. All three snippets are free to use — no sign-up, no API key. More distribution surfaces →

Badge

[![ClaudSkills](https://claudskills.com/badge/sepia.svg)](https://claudskills.com/skills/sepia/?utm_source=badge&utm_medium=readme&utm_campaign=skill_badge)

Security scan

Grade A · scanned 2026-10-25 — free static scan against the OWASP Agentic Skills Top 10.

No risk patterns were found in any of the ten OWASP-aligned categories. How grading works ›

✓ Prompt injection
✓ Data exfiltration
✓ Supply chain
✓ Reverse shell
✓ Credentials
✓ Execution
✓ Filesystem
✓ Persistence
✓ Obfuscation
✓ Network

Show this grade on your repo (click to copy):

[![Security: A](https://img.shields.io/badge/Security-A-2e7d32)](https://claudskills.com/skills/sepia/#security)