---
id: "concept-cnw-zip-extensions"
type: "concept"
source_timestamps: ["00:07:38", "00:08:00"]
tags: ["proprietary-formats", "developer-ecosystem"]
related: ["entity-conway", "concept-google-play-services-pattern", "entity-mcp"]
definition: "Anthropic's proprietary file format for packaging Conway agent extensions, sitting on top of the open MCP standard."
sources: ["s51-512k-leaked-code"]
sourceVaultSlug: "s51-512k-leaked-code"
originDay: 51
---
# .cnw.zip Extension Format

## Definition

[[entity-anthropic-d51|Anthropic]]'s proprietary file format for packaging [[entity-conway-d51|Conway]] agent extensions, sitting on top of the open [[entity-mcp-d51|MCP]] standard.

## What's Inside a `.cnw.zip`

Revealed in the leak (see [[claim-conway-existence]]), `.cnw.zip` packages bundle:

- **Custom interface panels** — UI components that render inside the Conway sidebar.
- **Specific information handlers** — bespoke logic for parsing/transforming source data.
- **Tools** designed to work *exclusively* inside the Conway environment.

## The Strategic Move

While the underlying data connections might use the open Model Context Protocol (MCP), the `.cnw.zip` packages add a proprietary *application layer* on top. This format is the mechanism by which Anthropic creates a proprietary **app store** for agents.

## The Developer's Dilemma

Developers face a binary choice:

1. Build a **standard, portable MCP tool** — works across many AI providers, but has *no built-in distribution*.
2. Build a **`.cnw.zip` extension** — gets featured in Anthropic's marketplace, but is *locked to their ecosystem*.

This is a textbook expression of the [[concept-google-play-services-pattern|Google Play Services Pattern]] and Step 4 of [[framework-anthropic-ecosystem-capture]].