diff --git a/modules/home/ai-agent/default.nix b/modules/home/ai-agent/default.nix
--- a/modules/home/ai-agent/default.nix
+++ b/modules/home/ai-agent/default.nix
@@ -31,6 +31,16 @@
   claudeSettings = {
     effortLevel = "medium";
     hooks = {
+      SessionStart = [
+        {
+          hooks = [
+            {
+              type = "command";
+              command = "cat ${./google-dev-doc-style.md}";
+            }
+          ];
+        }
+      ];
       TaskCompleted = [
         {
           hooks = [
diff --git a/modules/home/ai-agent/google-dev-doc-style.md b/modules/home/ai-agent/google-dev-doc-style.md
new file mode 100644
--- /dev/null
+++ b/modules/home/ai-agent/google-dev-doc-style.md
@@ -0,0 +1,14 @@
+Follow the Google developer documentation style guide when writing prose:
+
+- Be conversational and friendly, not stiff or robotic; avoid jargon and business-speak.
+- Write in second person ("you"), not "we" or "the user".
+- Use active voice so it's clear who's doing what.
+- Put conditions before instructions ("If X, do Y", not "Do Y if X").
+- Prefer short sentences and short paragraphs; get to the point.
+- Use sentence case for headings and titles, not title case.
+- Use numbered lists for sequential steps, bullet lists for unordered items.
+- Put UI element names in **bold**, code/commands/file names in `code font`.
+- Use descriptive link text, never "click here".
+- Use standard American English spelling and the serial (Oxford) comma.
+- Write for a global audience: avoid idioms and humor that don't translate, and use unambiguous date formats.
+- Don't pre-announce unreleased features or make promises about the future.