Add Fern docs platform: scaffolding, CI/CD, ecosystem diagram, and new pages

.github/workflows/fern-docs-ci.yml

@@ -0,0 +1,33 @@
+# Validates Fern docs configuration and checks for broken internal links on PRs.
+# Runs without a FERN_TOKEN — suitable for untrusted forks.
+name: Fern Docs CI
+
+on:
+  push:
+    branches:
+      - "pull-request/[0-9]+"
+  pull_request:
+    paths:
+      - 'docs/**'
+      - 'fern/**'
+      - 'package.json'
+
+jobs:
+  validate:
+    name: Validate docs
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: fern check
+        run: npm run docs:check
+
+      - name: Check broken links
+        run: npx fern docs broken-links

.github/workflows/fern-docs-preview.yml

@@ -0,0 +1,55 @@
+# Generates a shareable Fern preview URL for every docs PR and posts it as a comment.
+# Requires the FERN_TOKEN repository secret.
+name: Fern Docs Preview
+
+on:
+  push:
+    branches:
+      - "pull-request/[0-9]+"
+  pull_request:
+    paths:
+      - 'docs/**'
+      - 'fern/**'
+      - 'package.json'
+
+jobs:
+  preview:
+    name: Generate preview
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Generate preview
+        id: preview
+        run: |
+          output=$(npm run docs:preview 2>&1)
+          echo "$output"
+          url=$(printf '%s\n' "$output" \
+            | grep -oP 'https://[A-Za-z0-9./?&=_:%#~+-]*buildwithfern\.com[A-Za-z0-9./?&=_:%#~+-]*' \
+            | tail -n 1 \
+            | perl -CS -pe 's/\x{200B}//g; s/%E2%80%8B$//i')
+
+          echo "url=$url" >> "$GITHUB_OUTPUT"
+        env:
+          FERN_TOKEN: ${{ secrets.FERN_TOKEN }}
+
+      - name: Post preview URL
+        if: steps.preview.outputs.url != ''
+        uses: actions/github-script@v7
+        with:
+          script: |
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: '📖 **Docs preview:** ${{ steps.preview.outputs.url }}'
+            })

.github/workflows/publish-fern-docs.yml

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+# Publishes docs to production on every push to main that touches docs/fern,
+# and on manual dispatch. Requires the FERN_TOKEN repository secret.
+name: Publish Fern Docs
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'docs/**'
+      - 'fern/**'
+      - 'package.json'
+  workflow_dispatch:
+
+jobs:
+  publish:
+    name: Publish docs
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Publish
+        run: npm run docs:publish
+        env:
+          FERN_TOKEN: ${{ secrets.FERN_TOKEN }}

.gitignore

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+# Node / npm (project-local tooling environment for docs)
+node_modules/
+npm-debug.log*
+.npm/
+
+# Fern build output & cache
+.fern/
+.preview/
+
+# OS / editor
+.DS_Store
+
+# Local working files (not for commit)
+docs/ecosystem/*-outline.md
+guides/

.npmrc

@@ -0,0 +1,2 @@
+# Pin exact versions when adding dependencies, for reproducible installs.
+save-exact=true

.nvmrc

@@ -0,0 +1 @@
+22

Makefile

@@ -0,0 +1,21 @@
+.PHONY: docs-dev docs-restart docs-wait docs-check docs-preview
+
+docs-dev:
+	npm run docs:dev
+
+docs-restart:
+	-pkill -f "fern docs dev" 2>/dev/null || true
+	sleep 1
+	npm run docs:dev
+
+# Poll until the dev server responds — run this after backgrounding docs-restart
+docs-wait:
+	@echo "Waiting for http://localhost:3000 ..."
+	@until curl -sf http://localhost:3000 >/dev/null 2>&1; do sleep 3; done
+	@echo "Server ready."
+
+docs-check:
+	npm run docs:check
+
+docs-preview:
+	npm run docs:preview

docs/GPU_performance.md

@@ -191,7 +191,7 @@ Fine-grain control to improve performance by initializing a NCCL communicator to
 ### Miscellaneous flags 
 - --xla_gpu_cudnn_gemm_fusion=true (enables GEMM/bias fusion via cuDNN)
 - --xla_gpu_enable_cudnn_fmha=false (enables XLA pattern matcher to detect multi-headed attention pattern in JAX)
-- --xla_disable_hlo_passes=<> (turns off specific HLO passes; can be used for debugging)
+- `--xla_disable_hlo_passes=<...>` (turns off specific HLO passes; can be used for debugging)
 
 ## Previously used XLA Flags