Development Prerequisites

The Container Use MCP extension for Zed integrates the Container Use Model Context Protocol (MCP) server directly into the Zed editor. This integration provides coding agents with isolated, containerized environments to execute tasks safely and predictably.

To develop, install, or configure this extension, several system-level components and specific binaries must be present. These prerequisites ensure that the Zed extension can successfully locate and execute the cu (Container Use) binary to establish a communication channel via standard input/output (stdio).

Sources: README.md:1-5, extension.toml:1-4

Core System Dependencies

The extension is built using Rust and utilizes the Zed Extension API. Development requires the standard Rust toolchain and the zed_extension_api crate.

Rust Environment

The project is configured as a library with a crate type of cdylib, targeting the 2021 edition of Rust.

Sources: Cargo.toml:1-15

The cu Binary Requirement

The primary functional prerequisite is the cu binary from the Dagger Container Use project. The extension acts as a wrapper that invokes this binary.

Binary Acquisition

Currently, the cu binary must be built from source as the project is in active development. It must be accessible either in the system PATH or through a manually specified path in the editor settings.

Configuration and Permissions

For the extension to operate correctly, certain configurations must be applied within the Zed environment.

Project-Level Agent Rules

To ensure that coding agents within Zed utilize the containerized environment provided by the MCP server, a specific rules file must be present in the project root. This is a critical prerequisite for the "agent" functionality.

• File Name: .rules
• Source: https://raw.githubusercontent.com/dagger/container-use/main/rules/agent.md

Sources: README.md:27-31, configuration/installation_instructions.md:1-1

Extension Capabilities

The extension requires the ability to execute system processes, specifically the which command, to locate dependencies.

Sources: extension.toml:9-12

Development Configuration Settings

If the cu binary is not in the system PATH, it must be defined in the Zed settings.json. The extension uses the following data structure to parse these settings:

#[derive(Debug, Deserialize, JsonSchema)]
struct ContainerUseMcpSettings {
    /// Path to the cu binary (optional - will download if not provided)
    cu_path: Option<String>,
}

Sources: src/container_use_mcp.rs:10-14

Settings Example

{
  "context_servers": {
    "container-use-mcp": {
      "settings": {
        "cu_path": "/custom/path/to/cu"
      }
    }
  }
}

Sources: README.md:17-25

Summary of Execution Flow

When Zed initializes the extension, it follows a specific sequence to establish the MCP server connection.

The development and usage of this extension depend entirely on the availability of the cu binary and the correct configuration of the .rules file to direct agent behavior. Without these prerequisites, the extension will fail to start the context server or the agents will bypass the containerized environment.