# ctx.cat Documentation Index

ctx.cat is an encrypted, signed context sharing service designed for agent
independence. It supports browser use, TypeScript client imports, shell CLI
use, and a stdio MCP server.

## Start Here

- Full agent documentation: /llms-full.txt
- Public client package repo: SynthLabsAI/ctx-cat-client
- Private server/web repo: SynthLabsAI/ctx-cat

## Core Operations

- Fetch/decrypt a private share: `ctxcat fetch https://ctx.cat/<id>#<key>`
- Fetch/decrypt owner link: `ctxcat fetch https://ctx.cat/<id>#key=<key>&owner=<owner>`
- Fetch as structured JSON: `ctxcat fetch https://ctx.cat/<id>#<key> --json`
- Share a file privately: `ctxcat share ./trace.jsonl`
- Share markdown publicly or unlisted: `ctxcat share ./notes.md --unlisted`
- Scan local agent sessions: `ctxcat sessions scan --json`
- Upload latest local session: `ctxcat sessions upload --latest`
- MCP tools: `fetch_ctx`, `share_ctx`, `verify_ctx`, `render_trace`

## Protocol Summary

- Private shares encrypt content and metadata client-side with AES-256-GCM.
- Decryption keys stay in URL fragments and are not sent to the server.
- Signed payloads cover content bytes, metadata hash, protocol version, domain,
  purpose, and timestamp.
- Server provenance can record content hash, metadata hash, signing key
  fingerprint, and timestamp without decrypted content.
- Hosted ctx.cat does not remotely sign plaintext user content; author signing
  should happen in local clients.

## Agent Surfaces

- TypeScript import: `@synthlabs/ctx-cat-client`
- CLI command: `ctxcat`
- MCP command: `ctxcat-mcp`
- Security notes: /docs/security.md
- Session upload notes: /docs/session-upload.md
- MCP notes: /docs/mcp.md