By name: mb-skill-concept tier: skill calls: [] description: "Generate N concept variations of a site / asset on localhost in parallel, foreground subagents. Default 2. Operator picks one to publish. Used by /mb-site as the concept-generation step." loops: [ship]
skill-concept
A composable skill for generating concept variations. /mb-site calls this after the brief is locked, before the first publish.
Inputs
- The locked brief (path provided in the user message)
- Reference URLs (taste anchors, not templates)
- Conversion endpoint config (
.mainbranch/conversion.json)
Outputs
- N localhost-runnable HTML variations, each in its own subdir of the project repo (e.g.,
concepts/v1/,concepts/v2/) - A short comparison summary for the operator: hero artifact, palette, voice variant for each
- Operator picks one; that variation is promoted to the project root
Flow
- Spawn N foreground subagents (default 2). Each gets the same brief + reference URLs but is asked to make different decisions.
- Each subagent writes its variation. Foreground only — background writes are known to silently fail.
- Validate each variation: footer present, OG.svg under 1200×630, no AI tells in the copy.
- Render preview.
python3 -m http.serverfrom each subdir; open in browser. - Operator picks. One concept → promoted to repo root; others archived under
concepts/.
Foreground rule
Subagents MUST be foreground. The known background-subagent file-write bug means files appear written but don't persist. Foreground only. See references/concept-variations.md for the spawn pattern.