Explanation: pack structure — one plugin per skill

The convention

Every optional capability ships as a plugin, and each plugin contains exactly one skill. Plugins are grouped into pack families by directory, but the plugin boundary is the individual skill:

packs/
├── reports/                      # family: deliverable genres (container, NOT a plugin)
│   ├── exec-summary/             #   a plugin
│   │   ├── .claude-plugin/plugin.json
│   │   └── skills/exec-summary/SKILL.md
│   ├── academic/                 #   a plugin
│   ├── engineering/
│   ├── trend-analysis/
│   └── briefing/
├── market-research/              # family: methodology
│   ├── competitive-analysis/     #   a plugin
│   ├── customer-research/
│   ├── financial-analysis/
│   ├── market-sizing/
│   └── regulatory-review/
├── channels/                     # family: render adapters
│   ├── notebooklm/
│   ├── pdf/
│   ├── github-discuss/
│   └── github-issues/
└── trend-modeling/
    └── trend-modeling/

Each packs/<family>/<skill>/ is a self-contained Claude Code plugin: its .claude-plugin/plugin.json (validated against schemas/pack.schema.json) plus a flat skills/<skill>/SKILL.md and that skill’s evals/.

Why

The point is selective adoption. A clone that wants the executive-summary genre but not the academic one enables exec-summary and leaves academic disabled — it is never forced to adopt a whole pack to get one skill. New capabilities are added the same way: drop a new packs/<family>/<skill>/ plugin, register it in .claude-plugin/marketplace.json, and toggle it in harness.config.json packs[]. Nothing else changes.

This applies to all families uniformly — market-research, channels, and trend-modeling follow the same one-plugin-per-skill shape as reports, so the extension surface is consistent everywhere.

The control plane

harness.config.json packs[] lists each plugin by its (bare) name with an enabled flag and a source (bundled, or an external git/marketplace plugin). scripts/sync-packs.sh resolves each enabled plugin’s directory from the marketplace source path and materializes the set into Claude Code’s native enabledPlugins in the instance-local .claude/settings.local.json (<skill>@research-harness; gitignored, deep-merged with the template-managed .claude/settings.json). scripts/pack-toggle.sh <skill> on|off flips one plugin.

By default the five reports genres are enabled; every other plugin is disabled and opt-in.