braintrustdata · Luca Forstner (lforst) · Aug 19, 2026 · Aug 19, 2026 · Aug 19, 2026 · Aug 20, 2026
diff --git a/.changeset/add-node-engine.md b/.changeset/add-node-engine.md
@@ -0,0 +1,5 @@
+---
+"braintrust": major
+---
+
+feat(v4)!: Add Node Engine to package json
diff --git a/.changeset/reduce-api-to-a-minimum.md b/.changeset/reduce-api-to-a-minimum.md
@@ -0,0 +1,8 @@
+---
+"braintrust": major
+"@braintrust/otel": major
+"@braintrust/browser": patch
+"@braintrust/temporal": patch
+---
+
+ref!: Reduce API to a minimum that makes sense
diff --git a/.changeset/remove-ai-sdk-v3.md b/.changeset/remove-ai-sdk-v3.md
@@ -0,0 +1,5 @@
+---
+"braintrust": major
+---
+
+ref(ai-sdk)!: Remove AI SDK v3 support
diff --git a/.changeset/remove-eve-pre-034.md b/.changeset/remove-eve-pre-034.md
@@ -0,0 +1,5 @@
+---
+"braintrust": major
+---
+
+ref(eve)!: Bump minimum eve version to `0.34.0`
diff --git a/.changeset/remove-flue-pre-v1.md b/.changeset/remove-flue-pre-v1.md
@@ -0,0 +1,5 @@
+---
+"braintrust": major
+---
+
+ref(v4)!: Remove flue pre-v1 support
diff --git a/.changeset/remove-flush-async.md b/.changeset/remove-flush-async.md
@@ -0,0 +1,5 @@
+---
+"braintrust": major
+---
+
+ref!: Remove `flushAsync` option
diff --git a/.changeset/remove-js-braintrust-cli.md b/.changeset/remove-js-braintrust-cli.md
@@ -0,0 +1,5 @@
+---
+"braintrust": major
+---
+
+ref(v4)!: Remove JS Braintrust CLI
diff --git a/.changeset/remove-plugins-public-api.md b/.changeset/remove-plugins-public-api.md
@@ -0,0 +1,5 @@
+---
+"braintrust": major
+---
+
+ref!: Remove plugins as part of public API
diff --git a/.changeset/remove-zod-derived-types.md b/.changeset/remove-zod-derived-types.md
@@ -0,0 +1,5 @@
+---
+"braintrust": major
+---
+
+ref!: Remove Zod derived types from public SDK declarations
diff --git a/.github/workflows/checks.yaml b/.github/workflows/checks.yaml
@@ -236,11 +236,10 @@ jobs:
           pnpm install --frozen-lockfile || { echo "Baseline install failed"; git checkout "$CURRENT_REF"; exit 0; }
           pnpm run build || { echo "Baseline build failed"; git checkout "$CURRENT_REF"; exit 0; }
 
-          mkdir -p "$BASELINE_DIR/js/dev" "$BASELINE_DIR/js/util"
+          mkdir -p "$BASELINE_DIR/js/util"
           cp -R js/dist "$BASELINE_DIR/js/"
-          cp -R js/dev/dist "$BASELINE_DIR/js/dev/"
           cp -R js/util/dist "$BASELINE_DIR/js/util/"
-          echo "Copied js/dist, js/dev/dist, and js/util/dist to baseline"
+          echo "Copied js/dist and js/util/dist to baseline"
 
           git checkout "$CURRENT_REF"
 
@@ -473,17 +472,6 @@ jobs:
       - name: Run hermetic tests
         working-directory: ./js
         run: pnpm run test:checks
-      - name: Run zod v3 tests
-        if: matrix.zod-version == '3.25.34'
-        working-directory: ./js
-        run: |
-          pnpm test:zod-v3
-      - name: Run zod v4 tests
-        if: matrix.zod-version == '4.2.1'
-        working-directory: ./js
-        run: |
-          pnpm test:zod-v4
-
   checks-passed:
     name: checks-passed
     needs:

diff --git a/AGENTS.md b/AGENTS.md
@@ -25,6 +25,21 @@ mise install        # Install toolchain and dependencies
 pnpm run build      # Build all workspace packages (from repo root)
 ```
 
+## Public TypeScript APIs
+
+Do not derive SDK-owned public TypeScript types from Zod schemas (for example,
+with `z.infer`, `z.input`, `z.output`, or equivalent schema-derived aliases).
+Define public API types explicitly with interfaces, type aliases, or generated
+plain types. Generic APIs may still infer types from caller-provided schemas.
+When exporting a runtime validator, give it a compact public type such as
+`z.ZodType<PublicType>` and test that the validator and public type stay in sync.
+
+Zod-derived public declarations can expand into large schema implementation
+graphs. Those declarations are expensive for downstream TypeScript consumers to
+parse, instantiate, and type-check, increasing compile time, declaration size,
+and memory usage. They also expose validation-library implementation details as
+part of the SDK's API surface.
+
 ## Public API
 
 Keep public exports minimal. Generally, export only the requested runtime APIs and do not export types unless explicitly requested.

diff --git a/README.md b/README.md
@@ -37,19 +37,17 @@ Eval("Say Hi Bot", {
 Run it:
 
 ```bash
-BRAINTRUST_API_KEY=<YOUR_API_KEY> npx braintrust eval tutorial.eval.ts
+BRAINTRUST_API_KEY=<YOUR_API_KEY> npx bt eval tutorial.eval.ts
 ```
 
 ## Packages
 
-| Package                     | Purpose                                                                         | npm                                                                                                                                                          | Docs                                                                               |
-| --------------------------- | ------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------- |
-| `braintrust`                | Core JavaScript/TypeScript SDK for logging, tracing, evals, and CLI.            | [![npm: braintrust](https://img.shields.io/npm/v/braintrust.svg)](https://www.npmjs.com/package/braintrust)                                                  | [js/README.md](js/README.md)                                                       |
-| `@braintrust/browser`       | Browser-focused SDK integration with AsyncLocalStorage polyfill support.        | [![npm: @braintrust/browser](https://img.shields.io/npm/v/%40braintrust%2Fbrowser.svg)](https://www.npmjs.com/package/@braintrust/browser)                   | [integrations/browser-js/README.md](integrations/browser-js/README.md)             |
-| `@braintrust/langchain-js`  | Deprecated; use the LangChain integration in `braintrust` instead.              | [![npm: @braintrust/langchain-js](https://img.shields.io/npm/v/%40braintrust%2Flangchain-js.svg)](https://www.npmjs.com/package/@braintrust/langchain-js)    | [integrations/langchain-js/README.md](integrations/langchain-js/README.md)         |
-| `@braintrust/openai-agents` | Deprecated; use the OpenAI Agents integration in `braintrust` instead.          | [![npm: @braintrust/openai-agents](https://img.shields.io/npm/v/%40braintrust%2Fopenai-agents.svg)](https://www.npmjs.com/package/@braintrust/openai-agents) | [integrations/openai-agents-js/README.md](integrations/openai-agents-js/README.md) |
-| `@braintrust/otel`          | OpenTelemetry span processor and compatibility helpers for Braintrust tracing.  | [![npm: @braintrust/otel](https://img.shields.io/npm/v/%40braintrust%2Fotel.svg)](https://www.npmjs.com/package/@braintrust/otel)                            | [integrations/otel-js/README.md](integrations/otel-js/README.md)                   |
-| `@braintrust/temporal`      | Temporal client/worker plugin and workflow interceptors for Braintrust tracing. | [![npm: @braintrust/temporal](https://img.shields.io/npm/v/%40braintrust%2Ftemporal.svg)](https://www.npmjs.com/package/@braintrust/temporal)                | [integrations/temporal-js/README.md](integrations/temporal-js/README.md)           |
+| Package                | Purpose                                                                         | npm                                                                                                                                           | Docs                                                                     |
+| ---------------------- | ------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------ |
+| `braintrust`           | Core JavaScript/TypeScript SDK for logging, tracing, evals, and CLI.            | [![npm: braintrust](https://img.shields.io/npm/v/braintrust.svg)](https://www.npmjs.com/package/braintrust)                                   | [js/README.md](js/README.md)                                             |
+| `@braintrust/browser`  | Browser-focused SDK integration with AsyncLocalStorage polyfill support.        | [![npm: @braintrust/browser](https://img.shields.io/npm/v/%40braintrust%2Fbrowser.svg)](https://www.npmjs.com/package/@braintrust/browser)    | [integrations/browser-js/README.md](integrations/browser-js/README.md)   |
+| `@braintrust/otel`     | OpenTelemetry span processor and compatibility helpers for Braintrust tracing.  | [![npm: @braintrust/otel](https://img.shields.io/npm/v/%40braintrust%2Fotel.svg)](https://www.npmjs.com/package/@braintrust/otel)             | [integrations/otel-js/README.md](integrations/otel-js/README.md)         |
+| `@braintrust/temporal` | Temporal client/worker plugin and workflow interceptors for Braintrust tracing. | [![npm: @braintrust/temporal](https://img.shields.io/npm/v/%40braintrust%2Ftemporal.svg)](https://www.npmjs.com/package/@braintrust/temporal) | [integrations/temporal-js/README.md](integrations/temporal-js/README.md) |
 
 ## CLI `bt`
 

diff --git a/e2e/README.md b/e2e/README.md
@@ -80,7 +80,7 @@ Wrapper scenarios often create a root span with `testRunId` metadata and then le
 - Find the scenario root span first.
 - Scope raw payload snapshots by `root_span_id` using `payloadRowsForRootSpan(...)`.
 - Prefer normalized span-tree snapshots from `matchSpanTreeSnapshot(...)`. The `.json` sibling is the structural contract, and the `.txt` sibling is the ASCII tree for review; both are asserted and should be updated together.
-- If the wrapper has an explicit support matrix, reuse one shared test across version-specific scenario entries instead of duplicating the assertions. The AI SDK wrapper scenario uses this for supported v3-v6 package combinations.
+- If the wrapper has an explicit support matrix, reuse one shared test across version-specific scenario entries instead of duplicating the assertions. The AI SDK wrapper scenario uses this for its supported package combinations.
 
 ### Runner-wrapper scenario pattern
 
@@ -188,7 +188,7 @@ After any successful record run, stale cassette variants are cleaned only inside
 
 These scenarios have cassette wiring in place and will use cassettes once they're recorded:
 
-`anthropic-bedrock-instrumentation`, `anthropic-instrumentation`, `openai-instrumentation`, `openai-codex-instrumentation`, `ai-sdk-instrumentation`, `ai-sdk-otel-export`, `claude-agent-sdk-instrumentation`, `cohere-instrumentation`, `cursor-sdk-instrumentation`, `github-copilot-instrumentation`, `google-adk-instrumentation`, `google-genai-instrumentation`, `groq-instrumentation`, `huggingface-instrumentation`, `mistral-instrumentation`, `ollama-instrumentation`, `openrouter-agent-instrumentation`, `openrouter-instrumentation`, `wrap-langchain-js-traces`.
+`anthropic-bedrock-instrumentation`, `anthropic-instrumentation`, `openai-instrumentation`, `openai-codex-instrumentation`, `ai-sdk-instrumentation`, `ai-sdk-otel-export`, `claude-agent-sdk-instrumentation`, `cohere-instrumentation`, `cursor-sdk-instrumentation`, `github-copilot-instrumentation`, `google-adk-instrumentation`, `google-genai-instrumentation`, `groq-instrumentation`, `huggingface-instrumentation`, `mistral-instrumentation`, `ollama-instrumentation`, `openrouter-agent-instrumentation`, `openrouter-instrumentation`.
 
 ### Cassette format
 

diff --git a/e2e/config/pr-comment-scenarios.json b/e2e/config/pr-comment-scenarios.json
@@ -531,14 +531,6 @@
     "label": "AI SDK Instrumentation",
     "metadataScenario": "ai-sdk-instrumentation",
     "variants": [
-      {
-        "variantKey": "ai-sdk-v3",
-        "label": "v3 pinned"
-      },
-      {
-        "variantKey": "ai-sdk-v3-latest",
-        "label": "v3 latest"
-      },
       {
         "variantKey": "ai-sdk-v4",
         "label": "v4 pinned"
@@ -623,14 +615,6 @@
     "label": "Flue Instrumentation",
     "metadataScenario": "flue-instrumentation",
     "variants": [
-      {
-        "variantKey": "flue-v0-8-0",
-        "label": "v0.8 pinned"
-      },
-      {
-        "variantKey": "flue-v0-8-latest",
-        "label": "v0.8 latest"
-      },
       {
         "variantKey": "flue-v1-0-0-beta-3",
         "label": "v1 pinned"
@@ -654,9 +638,7 @@
     "label": "Eve Instrumentation",
     "metadataScenario": "eve-instrumentation",
     "variants": [
-      { "variantKey": "eve-v0", "label": "v0 pinned" },
-      { "variantKey": "eve-v0-provider", "label": "v0 provider minimum" },
-      { "variantKey": "eve-v0-latest-pinned", "label": "v0 latest pinned" },
+      { "variantKey": "eve-v0", "label": "v0.34 pinned" },
       { "variantKey": "eve-v0-latest", "label": "v0 latest" }
     ]
   },
@@ -762,20 +744,5 @@
         "variantKey": "vitest-evals-reporter"
       }
     ]
-  },
-  {
-    "scenarioDirName": "wrap-langchain-js-traces",
-    "label": "LangChain JS Wrapper Traces",
-    "metadataScenario": "wrap-langchain-js-traces",
-    "variants": [
-      {
-        "variantKey": "wrap-langchain-js-traces-v1",
-        "label": "v1 pinned"
-      },
-      {
-        "variantKey": "wrap-langchain-js-traces-v1-latest",
-        "label": "v1 latest"
-      }
-    ]
   }
 ]
diff --git a/e2e/helpers/prod-forwarding.ts b/e2e/helpers/prod-forwarding.ts
@@ -31,7 +31,6 @@ export async function initializeProdForwarding(): Promise<void> {
     const logger = initLogger({
       apiKey,
       appUrl: process.env.BRAINTRUST_APP_URL,
-      asyncFlush: false,
       forceLogin: true,
       projectName,
     });

diff --git a/e2e/package.json b/e2e/package.json
@@ -8,8 +8,8 @@
     "test:e2e:record": "node ./scripts/run-record-tests.mjs"
   },
   "devDependencies": {
+    "@braintrust/browser": "workspace:^",
     "@braintrust/deepseek-harness": "workspace:^",
-    "@braintrust/langchain-js": "workspace:^",
     "@braintrust/otel": "workspace:^",
     "@braintrust/seinfeld": "workspace:^",
     "@opentelemetry/api": ">=1.9.0",