MCP Bundles

ACORN packages its local stdio Model Context Protocol server as a target-specific .mcpb archive. The bundle contains manifest.json and one server/acorn or server/acorn.exe executable. The manifest follows MCPB 0.3, pinned to upstream revision 70fe3b34cd6dff1b3bba046638edc72a6467a4fb, and declares the same safe online read-only tools as acorn serve mcp.

Create a local bundle with acorn create mcp. Use --binary and --platform darwin|linux|win32 for a release or cross-compiled executable. --dry-run prints the manifest, inventory, and destination without writing. --kitfile ./Kitfile creates the bundle first and then idempotently upserts an authoring mcpServers entry named acorn using a relative path; resolved OCI layer identity is never written to authoring YAML.

Direct clients can run acorn serve mcp or use acorn sync --mcp. Synchronization configures the absolute executable path and does not install a bundle. A client that supports MCPB installation owns extraction and approval.

The default server is read-only. Global --offline removes tools that may contact external systems. Persistent mutation requires serve mcp --allow-mutation and an enabled local database. Bundles do not execute during creation, inspection, ModelKit packaging, or download; inspect their source and SHA-256 before installation.

Official release bundles target x86_64-unknown-linux-musl and x86_64-pc-windows-gnu, each with a SHA-256 sidecar and validation by @anthropic-ai/mcpb@2.1.2. Local macOS packaging is possible only by supplying a supported target binary contract; ACORN does not publish or claim a signed macOS MCPB release.