sepia
sepia handles structural and stylistic AI-writing patterns by text type: fiction gets narrative repair before polishing, professional documents receive venue rules, and users choose drafting, diagnosis, minimal edits, or full rewriting.
Project overview
sepia is a writing and revision Skill for AI agents. Fiction goes through narrative architecture, discourse flow, and surface style; release notes, PR replies, postmortems, tickets, and technical articles follow domain-specific rules. It supports drafting, diagnosis only, minimal revision, and full rewriting. Its aim is prose suited to real readers and venues, not guaranteed AI-detector evasion.
Core capabilities
Repair fiction before polishing sentences
Checks overexplained themes, excessively tidy causality and endings before addressing flow, rhythm, and syntax; selects a small set of appropriate interventions.
Route professional prose by document type
Release notes lead with user impact and breaking changes; PR replies answer first; postmortems emphasize timelines, mechanisms, and owned action items.
Separate diagnosis from editing
review produces an evidence-backed defect list without edits. refactor diagnoses before minimal changes, while recreate rebuilds from source facts and intent.
Preserve voice and protected material
Formal register is not itself a defect. Quotations and caller-protected ranges stay intact, while missing facts require a question or an explicit placeholder.
Installation and usage
The primary route below installs the full Claude Code plugin at user scope for use across projects. Codex users can select the native commands on the same page. The full package includes the router and direct-operation entries.
Let an AI Agent install it
Send this prompt to Codex, Claude Code, or another AI agent that can work with your local environment.
Help me install sepia from https://github.com/Nanako0129/sepia. Read README.md, skills/sepia/SKILL.md, and the plugin manifest for my host first. Confirm the agent I use, then install the complete plugin with its documented user-scope commands, retaining the canonical Skill and wrappers. Check the entries and run review on a non-sensitive passage I supply, reporting findings without editing files. Actual revision requires a separate request. Report installation and functional checks separately. Ask before requesting credentials, additional permissions, or overwriting existing files.- The chosen agent's command-line tool is installed and available.
- GitHub access and permission to install a user-scoped plugin.
- A short non-sensitive test passage rather than confidential tickets or incident material.
claude plugin marketplace add Nanako0129/sepia
claude plugin install sepia@sepia --scope user- 1Install the full user-scoped plugin
In a terminal with Claude Code available, run: claude plugin marketplace add Nanako0129/sepia claude plugin install sepia@sepia --scope user For Codex, use: codex plugin marketplace add Nanako0129/sepia codex plugin add sepia@sepia Choose only the command group for your host.
- 2Start with diagnosis only
Enter /sepia-review in Claude Code or $sepia-review in Codex, attach the passage, and identify its document type. Inspect findings and quoted evidence, and confirm that the original remains unchanged.
- 3Choose the revision scope
Use sepia-refactor for minimal edits, sepia-recreate for a full rewrite, or sepia-write for a new draft, with the host's / or $ prefix. Name the target files, facts, and protected ranges, and review the output before accepting it.
Confirm that sepia and its operation entries appear. Run sepia-review on a short passage and check for quoted evidence without file edits. Only then explicitly request sepia-refactor and verify that facts, quotations, and protected content remain intact. Visible entries establish installation readiness, not editing quality.
- Use /sepia-review in Claude Code or $sepia-review in Codex; other operations follow the README's matching entries.
- Skills CLI is another documented route, but runtime behavior on other hosts has not been exercised individually.
- Do not install sepia-write, sepia-review, or other wrappers alone; they depend on the sibling canonical Skill.
Use cases
Make release notes concrete
Replace vague promotion with changes, user impact, and migration steps, without inventing unsupported data or change evidence.
Review professional replies
Use review to check whether PR or ticket replies answer the question and supply evidence, without modifying the existing record.
Revise fiction architecture
Examine plot and narration issues before deciding between local revision and a full rewrite, preserving deliberate authorial choices.
Assessment
The README and canonical Skill distinguish document routing and editing authority more clearly than a simple word-replacement list. They also separate research findings, editorial inferences, and verification claims. AgentMatter reviewed public materials only; installation, editing quality, and detector behavior were not tested.
Why it may be useful
- Different routes for fiction and professional documents.
- Clear boundaries across four operations.
- Explicit treatment of quotations, protected ranges, and missing facts.
What to know first
- AgentMatter has not installed or tested editing quality; the author's entry-point installation checks are not per-platform behavior tests.
- Rules combine research findings and editorial heuristics; they do not guarantee detector outcomes or factual accuracy.
- Direct-operation wrappers depend on the canonical Skill and must not be installed alone.
README
sepia
Overview
sepia handles structural and stylistic AI-writing patterns by text type: fiction gets narrative repair before polishing, professional documents receive venue rules, and users choose drafting, diagnosis, minimal edits, or full rewriting. De-AI writing skill for Agent Skills-compatible agents, with native plugin packaging and separate fiction and professional prose routes.
Getting started
- The primary route below installs the full Claude Code plugin at user scope for use across projects. Codex users can select the native commands on the same page. The full package includes the router and direct-operation entries.
- Fiction uses three passes: narrative architecture, discourse flow, and surface style, without applying every rule to every piece.
- Professional prose combines a shared checklist with domain rules for concrete information and venue-appropriate register.
- Confirm that sepia and its operation entries appear. Run sepia-review on a short passage and check for quoted evidence without file edits. Only then explicitly request sepia-refactor and verify that facts, quotations, and protected content remain intact. Visible entries establish installation readiness, not editing quality.
Configuration
claude plugin marketplace add Nanako0129/sepia
claude plugin install sepia@sepia --scope user