Deed: MCP server, setup and security

What Deed does

According to its repository: “Contract-first programming language: check types, effects, capabilities and contracts in agent-written modules and review changes for new authority.”

An MCP server gives an AI agent extra tools it calls during the conversation: the agent reads their description, decides to use them and gets the result back. Deed is listed under Developer tools, a category of 475 servers in the directory, where it ranks #391 by stars.

Topics declared by the repository: programming-language, language, capability-based-security, compiler, design-by-contract, effect-system.

Installing and connecting Deed

Distribution modes declared in the official MCP registry:

• Cargo crate (Rust)

Like any MCP server, you declare it in your client's configuration (Claude Desktop, Claude Code, Cursor, VS Code, Codex…): a name, the command that starts it or its URL, and any environment variables. The client then starts it and lists its tools. Project language: Rust. Listed systems: macOS, Windows, Linux.

Security: what to check

An MCP server runs code with the rights you give it, and the model reads its tool descriptions: a malicious or compromised server can hijack the agent. Read the code, or pick a maintained and widely used server, before connecting it.

None of the risk signals we track (system access, secrets, missing licence, abandonment) applies to Deed. That does not replace reading the code.

Good practice: grant only the rights needed (least privilege), require human approval for irreversible actions, and run the AI agent security check.

Project activity and maintenance

Created on July 25, 2026, the deed-lang/deed repository has 9 stars and 0 forks, with 0 open issues. It has more stars than 24% of the servers in the directory. Last change 2 months ago. Version published in the registry: 0.2.13 (August 14, 2026).

Stars measure attention, not quality: a recent, heavily promoted project can collect them fast, while a useful but niche server will have few.