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+# CLAUDE.md — Agent operating instructions for Tapir
+
+Read this first if you are an agent (or human) starting a work session in this repo.
+It tells you how to work here. For *what* and *why*, read `README.md` and the guardrail
+docs it indexes.
+
+## Orientation order
+
+1. `README.md` — what Tapir is, links to all guardrails.
+2. `VISION.md` — the staged Definition of Success. **Stage 0 ("useful to me") is the gate.**
+   Do not build Stage 1+ machinery before Stage 0 holds.
+3. `DECISIONS.md` — the ADRs. Decisions are settled here; do not re-litigate without a new ADR.
+4. `docs/architecture/architecture.md`, `docs/data-model.md`, `docs/use-cases/*.feature`.
+5. `docs/homelab-integration.md` — the concrete endpoints/conventions you'll need.
+
+## How to work in this repo
+
+- **Trunk-Based Development (ADR-009).** Commit directly to `main`. One logical change per
+  commit. Every commit deployable. No feature branches or PRs for solo/agent work — the only
+  exception is a short-lived `agent/<desc>` branch when another agent is *simultaneously*
+  active on this repo, merged within the same session.
+- **Run the quality gate before every push.** `task check` (once a Taskfile exists). CI is the
+  gate, not branch protection — do not enable branch protection on this repo.
+- **Conventional commits.** `feat:`, `fix:`, `chore:`, `docs:`, `refactor:`. Subject line says
+  what; body says why.
+- **Language is Go (ADR-001).** Do not introduce Python or a second language. If you think you
+  need one, that's a new ADR with a real justification, not a default.
+
+## Things that look reusable but are NOT — read before "reusing"
+
+These caused real mistakes that were caught and corrected; the corrections are load-bearing.
+
+- **The `llm` package is COPIED from `hyperguild/ingestion`, not imported (ADR-004).** Tapir
+  owes that repo nothing at the dependency level. Do not add `hyperguild/ingestion` as a Go
+  module dependency to "share" code. If the copied `llm` needs changes, change Tapir's copy.
+- **The brain sink is HTTP to brain-mcp, NOT the filesystem `brain` package (ADR-005).**
+  `hyperguild/ingestion`'s `internal/brain` writes files into a brain git checkout on disk.
+  That is the wrong model for Tapir. The brain sink calls brain-mcp's `brain_ingest` tool over
+  HTTP. Do not copy or replicate the filesystem brain package.
+- **YouTube/Vimeo OAuth is written fresh (ADR-006).** `hyperguild/ingestion`'s `internal/oauth`
+  is the MCP *server's inbound* auth (client_credentials). It has nothing to do with *outbound*
+  OAuth to video providers despite the shared name. Use `golang.org/x/oauth2`.
+
+## Settled decisions you should not "helpfully" reopen
+
+(See `DECISIONS.md` for full rationale. Listed here so you don't propose them.)
+
+- **No Supabase** — reuse Dex / ESO+1Password / Postgres (ADR-002).
+- **No global cross-tenant video/transcript table** — per-user isolation (data-model). Dedup
+  across users is a Future C concern, not a Stage 0/1 default.
+- **No audio-download + speech-to-text in the core path** — captions-first (ADR-007). STT is a
+  deferred, bounded optional component.
+- **No public SaaS / sign-up / billing / Google OAuth verification at scale** — Future C,
+  deferred behind the Stage 0 gate (ADR-008).
+
+## Architecture stance for new code
+
+- **Clean Architecture, dependencies point inward.** The engine (use cases) depends only on the
+  ports (`VideoSource`, `Summarizer`, `Sink`, `SecretStore`). Concrete providers, the AI router,
+  stores, and sinks are adapters. Adding a video provider or a sink = a new adapter implementing
+  the interface, nothing in the engine changes. This is what keeps "standalone vs homelab" a
+  wiring choice (ADR-003).
+- **BDD.** The `docs/use-cases/*.feature` files are the behavior spec. New behavior gets a
+  scenario; the use-case core is tested through fake adapters, not live YouTube/brain.
+
+## Provenance (where this design came from)
+
+- The reuse decisions came from **Spike S5**, recorded at
+  `infra/docs/superpowers/handoffs/2026-06-02-video-adapter-placement.md` (read it for the
+  per-package lift-vs-copy analysis).
+- The `llm` package source is `hyperguild/ingestion/internal/llm` (`Client` + `Router`).
+- The standalone-first framing, the Supabase/Python rejections, and the staged success
+  definition came from a planning + grill session on 2026-06-02 (claude.ai). The conclusions are
+  in `VISION.md` and `DECISIONS.md`; this file is the operational distillation.