chore(e2e): follow-up fixes for PR #1920 review feedback

.agents/skills/e2e-tests/SKILL.md

@@ -53,6 +53,7 @@ Cassettes mock provider HTTP responses (OpenAI, Anthropic, ...) so scenarios tha
   Then run again in `BRAINTRUST_E2E_CASSETTE_MODE=replay` with no provider keys to confirm the cassette is sufficient.
 
 - Volatile fields in request bodies (e.g. AI-SDK `experimental_generateMessageId`) need a per-scenario filter. Add the scenario name and a `FilterSpec` to `e2e/helpers/cassette-filters.mjs`. The cassette layer is backed by `@braintrust/seinfeld` (`dev-packages/seinfeld`); the preload entry point is `e2e/helpers/cassette-preload.mjs`.
+- **After recording, always inspect the cassette for leaked API keys before committing.** The recorder redacts common patterns (`paranoid` preset), but confirm that no real keys appear in request headers, response bodies, or any URL query parameters. If a key slips through, remove the cassette, add a custom `redact` rule, and re-record.
 
 ## Preferred Patterns
 

dev-packages/seinfeld/README.md

@@ -5,24 +5,16 @@ Generic VCR/cassette library for Node.js, built on [MSW](https://mswjs.io). Reco
 ## Features
 
 - **Normalizers** (always-on, lossy) transform requests before matching. They strip volatile fields like `Authorization` headers, dynamic IDs (`experimental_generateMessageId`), or query nonces so two structurally-identical requests still match across runs. Their output is internal — never serialized.
-- **Redactors** (opt-in) transform what gets persisted to disk. They mask credentials before the cassette hits version control. Disabled by default; cassettes contain the real on-the-wire bytes unless you opt in.
+- **Redactors** transform what gets persisted to disk. They mask credentials before the cassette hits version control. The `'paranoid'` preset is applied by default; pass `redact: []` to disable.
 
 ## Security note
 
-> **Cassettes contain real request and response bytes by default, including `Authorization` headers.** This is the safer default for fidelity (downstream consumers see real responses) but it means you must either (a) enable redaction, (b) write a custom `RedactionConfig`, or (c) add cassette files to `.gitignore` if they may contain credentials.
-
-Three body-redaction gaps are worth knowing:
+Three body-redaction gaps are worth knowing even with the default `'paranoid'` preset:
 
 1. **Non-canonical content-type** — some servers return JSON with `Content-Type: text/plain`. `redactBodyFields` covers this because seinfeld attempts to parse `text` bodies as JSON before masking.
 2. **SSE event data** — streaming endpoints (OpenAI, Anthropic) emit JSON in `data:` lines. `redactBodyFields` applies to parseable `data:` lines; `redactBodyText` handles non-JSON SSE content.
 3. **Plain-text credentials** — form-encoded bodies, XML, or log-like text are opaque to field-path rules. Use `redactBodyText` with a regex.
 
-For cassettes committed to version control, use the `'paranoid'` preset, which covers all three paths:
-
-```ts
-createCassette({ name: "demo", redact: "paranoid" });
-```
-
 `'paranoid'` redacts credential headers, common credential field names at any JSON depth (`apiKey`, `token`, `secret`, `password`, `authorization`), and Bearer / `sk-` style tokens in text bodies.
 
 To detect misconfigurations at record time, add `strict: true`:

dev-packages/seinfeld/src/format/v1.ts

@@ -3,8 +3,11 @@ import { z } from "zod";
 /**
  * Zod schema for cassette format version 1.
  *
- * Validates cassettes at load time so corrupt files fail loudly rather than
- * mysteriously silent at match time.
+ * Cassette files carry a `version` field so that: (a) load-time validation
+ * fails loudly on corrupt files rather than silently at match time, and
+ * (b) a future breaking change can introduce v2 while the library still reads
+ * older cassettes without ambiguity. See `format/index.ts` for the dispatch
+ * logic and the rule for when to bump the version.
  */
 
 export const CURRENT_FORMAT_VERSION = 1 as const;

dev-packages/seinfeld/src/recorder.ts

@@ -348,7 +348,7 @@ export interface CassetteOptions {
   store?: CassetteStore;
   /** Filter spec (matching-only normalization). */
   filters?: FilterSpec;
-  /** Redaction spec (applied to persisted bytes). Defaults to none. */
+  /** Redaction spec (applied to persisted bytes). Defaults to `'paranoid'`. Pass `[]` to disable. */
   redact?: RedactionSpec;
   /** Hosts to intercept. Other hosts pass through. Defaults to all hosts. */
   hosts?: Array<string | RegExp>;
@@ -403,7 +403,7 @@ export function createCassette(options: CassetteOptions): Cassette {
       options.store ?? createJsonFileStore({ rootDir: DEFAULT_CASSETTE_DIR }),
     matcher: options.matcher ?? createDefaultMatcher(),
     filters: options.filters,
-    redact: options.redact,
+    redact: options.redact ?? "paranoid",
     hosts: options.hosts,
     passthroughHosts: options.passthroughHosts,
     threshold: resolveThreshold(options.externalBlobThreshold),