CampaignForge + ContentForge

Sweet spot is 3-4 parallel agents: Beyond 4, prompt quality drops and merge review gets sloppy. The real constraint is file isolation, not compute. With 3 repos, the ceiling is ~5 agents if file boundaries are clean.

Feature branches prevent same-repo conflicts: Agents C and D in campaignforge-app worked on separate branches (feat/cost-session-manager, feat/pipeline-orchestrator), then merged sequentially. Zero conflicts.

Independent agents can converge on identical fixes: Both the a11y and Lighthouse agents independently identified and fixed the same CSS cascade issue (@layer base wrapping, :where() scoping) with byte-identical diffs. Merge was clean because Git detected identical changes.

CAPI Worker type errors are IDE-only: Cloudflare Workers have their own tsconfig with @cloudflare/workers-types. The IDE picks up the root tsconfig which doesn't know about Request/Response/fetch globals. Not real errors.

MDX body_html requires JSX-safe formatting: Raw HTML from JSON has nested block elements on same lines, bare <br> tags, and ~ chars parsed as strikethrough. Conversion script needed multi-pass formatting: self-close void tags, escape tildes to ~, and split every block element onto its own line.

Astro dynamic components need static imports: client:visible hydration fails with dynamic component references (NoMatchingImport). Must use conditional static rendering: {tc === 'EFCCalculator' && <EFCCalculator client:visible />}.

Parallel agents for tool implementations: 4 agents dispatched simultaneously, each handling 2-3 tools. All completed in ~17 minutes. Logic/data separation (*.logic.ts, *.data.ts) enabled clean parallelization with zero merge conflicts.

Astro 5 Content Layer API: entry.render() is gone. Use import { render } from 'astro:content' then render(entry). Content collections need glob() loader from astro/loaders.

shadcn-svelte + Tailwind v4: @apply border-border fails — Tailwind v4 doesn't know custom vars via @apply. Use @theme inline to declare all HSL color vars, then use raw CSS instead of @apply for base styles.

shadcn-svelte components need WithElementRef: The cn utility must also export WithElementRef and WithoutChildrenOrChild types for sidebar/rail components.

MDX in Content Collections: HTML (tables, callouts, step-lists) works inline in MDX. No need to convert to custom components yet — the prose CSS styles handle it.

Astro 5 Content Collections: Uses src/content.config.ts (not src/content/config.ts). The z import from astro:content shows deprecation warnings.

Tailwind v4: No tailwind.config.ts needed. Uses @tailwindcss/vite plugin. The @astrojs/tailwind integration conflicts — use the Vite plugin directly.

Remote agents failed: Overnight scaffold agents couldn't auth with GitHub. Local execution worked first try.