Thanks for adding MCPB support! A few things to address before merging:

Hardcoded version in manifest

mcpb-manifest.json hardcodes "version": "0.8.0" which will drift from package.json immediately. This should either be injected automatically by the pack script (e.g., read from package.json at build time) or removed if the tooling doesn't require it.

.mcpb-stage and *.mcpb not gitignored

If the pack script fails midway, the staging directory will be left behind and could accidentally get committed. Please add .mcpb-stage and *.mcpb to .gitignore.

pack:mcpb script is fragile

The inline shell pipeline is long and hard to maintain. Consider moving it to scripts/pack-mcpb.sh. The leading rm -rf .mcpb-stage also silently deletes anything at that path.

Tool descriptions may drift

The tools array in the manifest duplicates names and descriptions already defined in source code — these could get stale over time. Worth adding a validation step or generating this section.