diff --git a/.github/workflows/docs-nav.yaml b/.github/workflows/docs-nav.yaml
new file mode 100644
index 00000000..fc4c8152
--- /dev/null
+++ b/.github/workflows/docs-nav.yaml
@@ -0,0 +1,32 @@
+name: Docs navigation
+
+permissions:
+  contents: write
+  pull-requests: write
+
+on:
+  workflow_dispatch:
+  pull_request:
+    paths:
+      - "docs/sdks/**"
+      - "scripts/gen-docs-nav.sh"
+      - ".github/workflows/docs-nav.yaml"
+
+jobs:
+  gen-docs-nav:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v5
+        with:
+          ref: ${{ github.event.pull_request.head.ref }}
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      # jq is preinstalled on GitHub-hosted ubuntu runners.
+      - name: Regenerate docs navigation
+        run: scripts/gen-docs-nav.sh
+
+      - name: Auto-commit docs.json navigation
+        uses: int128/update-generated-files-action@v2
+        with:
+          commit-message: "Chore: regenerate docs navigation"
diff --git a/docs/docs.json b/docs/docs.json
index e7e14135..2a0e3fd0 100644
--- a/docs/docs.json
+++ b/docs/docs.json
@@ -11,37 +11,39 @@
     "groups": [
       {
         "group": "Getting Started",
-        "pages": ["overview"]
+        "pages": [
+          "overview"
+        ]
       },
       {
         "group": "API Reference",
         "pages": [
+          "sdks/analytics/README",
+          "sdks/apikeys/README",
+          "sdks/benchmarks/README",
+          "sdks/betaanalytics/README",
+          "sdks/byok/README",
           "sdks/chat/README",
-          "sdks/responses/README",
-          "sdks/models/README",
-          "sdks/embeddings/README",
-          "sdks/rerank/README",
-          "sdks/images/README",
-          "sdks/tts/README",
-          "sdks/stt/README",
-          "sdks/videogeneration/README",
           "sdks/classifications/README",
-          "sdks/generations/README",
-          "sdks/endpoints/README",
-          "sdks/providers/README",
           "sdks/credits/README",
-          "sdks/apikeys/README",
-          "sdks/oauth/README",
-          "sdks/byok/README",
-          "sdks/presets/README",
-          "sdks/guardrails/README",
           "sdks/datasets/README",
+          "sdks/embeddings/README",
+          "sdks/endpoints/README",
           "sdks/files/README",
-          "sdks/analytics/README",
-          "sdks/betaanalytics/README",
-          "sdks/benchmarks/README",
+          "sdks/generations/README",
+          "sdks/guardrails/README",
+          "sdks/images/README",
+          "sdks/models/README",
+          "sdks/oauth/README",
           "sdks/observability/README",
           "sdks/organization/README",
+          "sdks/presets/README",
+          "sdks/providers/README",
+          "sdks/rerank/README",
+          "sdks/responses/README",
+          "sdks/stt/README",
+          "sdks/tts/README",
+          "sdks/videogeneration/README",
           "sdks/workspaces/README"
         ]
       }
diff --git a/scripts/gen-docs-nav.sh b/scripts/gen-docs-nav.sh
new file mode 100755
index 00000000..436b3dc2
--- /dev/null
+++ b/scripts/gen-docs-nav.sh
@@ -0,0 +1,60 @@
+#!/usr/bin/env bash
+# Regenerate the "API Reference" navigation group in docs/docs.json from the
+# service pages Speakeasy emits under docs/sdks/<tag>/README.mdx.
+#
+# Run this after `speakeasy run` so new API sections appear in the sidebar
+# without hand-editing docs.json. Only the "API Reference" group's `pages`
+# array is rewritten; every other part of docs.json is preserved untouched.
+# Pages are listed alphabetically by tag. Idempotent: running with no doc
+# changes leaves docs.json byte-identical.
+#
+# Requires: bash, jq. No network, no toolchain.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$ROOT"
+
+DOCS_JSON="docs/docs.json"
+GROUP="API Reference"
+
+if [[ ! -f "$DOCS_JSON" ]]; then
+	echo "missing $DOCS_JSON" >&2
+	exit 1
+fi
+
+# Collect service page paths (docs.json paths are repo-doc-root-relative and
+# carry no extension), sorted alphabetically by tag.
+pages=()
+while IFS= read -r readme; do
+	# docs/sdks/<tag>/README.mdx -> sdks/<tag>/README
+	rel="${readme#docs/}"
+	pages+=("${rel%.mdx}")
+done < <(find docs/sdks -mindepth 2 -maxdepth 2 -name 'README.mdx' | sort)
+
+if ((${#pages[@]} == 0)); then
+	echo "no service pages found under docs/sdks/*/README.mdx" >&2
+	exit 1
+fi
+
+# Build a JSON array of the page paths.
+pages_json="$(printf '%s\n' "${pages[@]}" | jq -R . | jq -s .)"
+
+# Rewrite only the matching group's pages. Fail loudly if the group is absent
+# so a renamed/missing group never silently produces an empty sidebar.
+tmp="$(mktemp)"
+jq --indent 2 \
+	--arg group "$GROUP" \
+	--argjson pages "$pages_json" '
+	(.navigation.groups
+		| map(select(.group == $group))
+		| length) as $matches
+	| if $matches == 0 then
+		error("group \"" + $group + "\" not found in navigation.groups")
+	  else . end
+	| .navigation.groups |= map(
+		if .group == $group then .pages = $pages else . end
+	  )
+' "$DOCS_JSON" >"$tmp"
+
+mv "$tmp" "$DOCS_JSON"
+echo "updated $DOCS_JSON: ${#pages[@]} pages in \"$GROUP\""