Affirm Contract C1 (no external side effects) under agentic-first

Going agentic (ADR-0001) makes acting in the world mechanically possible in the rebuild for the first time. We affirm Contract clause C1 (no external side effects) as the one line that "everything agentic, vemos depois" does not defer. The canonical invariant lives in CONTRACT.md; this ADR records why it is fixed from the start, not restated here.

Status

accepted

Why this one isn't deferred

"Everything agentic, vemos depois" (ADR-0001) defers capability guardrails — gates, determinism, reproducibility. C1 is a different kind of thing: it is identity, not reliability. Going agentic is exactly when an unattended 3h beat is one bad tool-call away from editing the mentee's repo, so the line is fixed now, not "later". Recording it here stops a future change from quietly treating "the agent can write" as a feature rather than a violation of what the edge is.