cowrite

cowrite is a skill for Claude Code from SpaceZephyr/cowrite. It costs 59 tokens per session (1,560 once invoked), scanned A, original, MIT.

A local, Notion-like writing canvas that lets an AI agent create and edit Markdown pages in a live browser editor. Markdown is plain text written with simple symbols for headings, links, and other formatting.

In plain words
What is it for?
Use it to open the canvas, list pages, read and update existing content, create new pages, and upload local images or self-contained HTML files.
Why use it?
It lets users see and edit generated pages immediately in one local workspace instead of passing documents back and forth.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions Codex.

Part of the cowrite plugin — 8 skills, 1 MCP server shipped together

Good fit Use it to open the canvas, list pages, read and update existing content, create new pages, and upload local images or self-contained HTML files.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/spacezephyr/cowrite/cowrite
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 SpaceZephyr/cowrite --skill cowrite
Clone the repo
git clone --depth 1 https://github.com/SpaceZephyr/cowrite

Made for: Claude Code.

Or install cowrite, the plugin that ships this one along with the rest of its 8 skills, 1 MCP server.

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 cowrite

README.md
[![agentmods](https://agentmods.dev/badge/skills/spacezephyr/cowrite/cowrite.svg)](https://agentmods.dev/skills/spacezephyr/cowrite/cowrite)
Your own site
<a href="https://agentmods.dev/skills/spacezephyr/cowrite/cowrite"><img src="https://agentmods.dev/badge/skills/spacezephyr/cowrite/cowrite.svg" alt="Measured on agentmods" height="20"></a>
Per session 59 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,560 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00059 $0.01560
Opus 5 $0.00030 $0.00780
Sonnet 5 $0.00012 $0.00312
Haiku 4.5 $0.00006 $0.00156

Measured 8d ago against content hash 082a9c14ab35, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

cowrite 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 8d 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/cowrite/SKILL.md · 47 lines

How it starts

The opening of the file, as written. The whole thing — 47 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cowrite

Cowrite is a local Notion-like writing canvas. An installed plugin automatically prepares and starts the production canvas at http://127.0.0.1:4320; source development uses Vite (normally http://127.0.0.1:4321). The user sees every page in a live browser editor and can edit at any time. You operate the same pages through the cowrite_* MCP tools; your writes appear in the user's editor within seconds.

Tools

  1. cowrite_get_status — verify the service and return the local browser canvas URL. Use when the user asks to start/open Cowrite.

  2. cowrite_list_pages — list pages (title, creation prompt, revision; no content). Pages with a prompt and revision: 1 are waiting to be written.

  3. cowrite_get_page — read one page with full Markdown content and current revision. Always call immediately before updating.

  4. cowrite_create_page — create a page with finished Markdown content. Use when the user says "在 cowrite 里创建/写一篇 …".

  5. cowrite_update_page — replace a page's Markdown content. Requires expected_revision from cowrite_get_page.

  6. cowrite_upload_asset — copy a local image or self-contained HTML file into Cowrite's asset store; returns a /assets/... url.

  7. cowrite_insert_after — insert one Markdown/HTML block right after the paragraph containing an exact anchor substring. Requires expected_revision.

Typical tasks

  • Create: the user describes what to write → write the article in Markdown → cowrite_create_page with a clear title and the full content. Tell the user the page is ready in Cowrite.
  • Fulfill a creation prompt: a pasted command names a page ID, or cowrite_list_pages shows a pending page → read it, write content that satisfies its prompt, update it.
  • Modify: the user references an existing page ("那篇 X 的文章") → find it via cowrite_list_pages, read it, apply the requested change while preserving everything else, write back.
  • Create from the current Page (pasted command from the top-level cowrite button): read the named page as both context and write target, follow the supplied creation requirement, and choose the best bundled Skill. Append continuations or derivative content unless the user explicitly asks to rewrite or replace something. Update the complete Markdown with expected_revision and preserve unrelated content.

Read the full file on GitHub · 47 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. 8d ago First seen · 47 lines · 59 tokens per session scan A 082a9c14ab35

Subscribe to this mod's changes

cowrite is a skill published in the GitHub repository SpaceZephyr/cowrite (91 stars, last pushed 1mo ago), licensed MIT. It adds 59 tokens to every session and 1,560 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 2026-08-30.

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