refactor: ban ambiguous origin label

AGENTS.md

@@ -119,8 +119,9 @@ Real-API tests and demos read `DEEPSEEK_API_KEY`, optional `DEEPSEEK_BASE_URL`,
 - **Trust TypeScript at typed same-process boundaries.** Do not add runtime validation, fallback behavior, or hostile-input tests solely for values the static interface requires; validate at parser/config, queued, model/tool JSON, durable/file, worker, process, and wire boundaries.
 - **Source plane vs artifact plane, never mixed.** Static gates and tests resolve workspace imports through tsconfig `paths` to `src` and pass on a clean tree; gates consuming built `lib/` declare that dependency ([layout](docs/development.md#typescript-project-layout)).
 - **Keep compiler faces explicit.** A package with both Host and Client programs exposes face-specific leaf configs and a solution-only root; repo-wide programs seed a face config, never the root solution ([layout](docs/development.md#typescript-project-layout)).
-- **An empty `catch` names what it swallows** and why nothing else can reach it; keep the `try` to one statement.
-- **Keep comments local.** Do not restate code, explain distant behavior unless locally required, or expand unrelated comments ([rationale](.agents/notes/implemented/process/2026-08-09-concrete-prose-names-actors-and-recorded-facts.md)).
+- **An empty `catch` names the swallowed error** and why; keep its `try` to one statement.
+- **Keep comments local.** Do not restate code, expand unrelated comments, or explain distant behavior without local need ([rationale](.agents/notes/implemented/process/2026-08-09-concrete-prose-names-actors-and-recorded-facts.md)).
+- **Ban `prove` + `nance`** ([rule](.agents/notes/implemented/process/2026-08-26-ban-ambiguous-origin-label.md)).
 - **Prefer symmetry for parallel values**; unexplained asymmetry usually signals a missed extraction.
 - **Tests describe behavior, not correctness.** Change obsolete behavior with its tests; explain why in the PR.
 - **Non-trivial changes MUST include an Agent Note in the same PR;** only mechanical/local edits are exempt ([scope](.agents/notes/README.md#when-to-write-one)). Archived notes are frozen: never edit or treat them as current authority ([archive policy](.agents/notes/README.md#archiving-and-deletion)).