I have been experimenting with ways to solve this problem and I ended up designing something I am calling the Agent Context Protocol, or MCP, which defines an AGENT.md and specifications for a specialized agent directory tree which includes templates for: commands, designs, milestones, and tasks.
Commands can be invoked by sending messages like `@acp.init` or `@acp.commit` for core ACP commands, or `@my-project.deploy` for project specific commands. Extension packages can be installed with a simple `@acp.package-install` ACP command.
Please consider checking out the README.md for a more advanced explanation of how ACP works, what problems it solves, and why it was created.