diff --git a/Jenkinsfile b/Jenkinsfile
index f16bd79..4f98960 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -1,10 +1,10 @@
 pipeline {
     agent any
     environment {
-        OPENAI_API_KEY = credentials('OPENAI_API_KEY')
+        XAI_API_KEY = credentials('XAI_API_KEY')
         GITEA_TOKEN = credentials('GITEA_TOKEN')
         GITEA_URL = 'https://git.jb9.uk'
-        CODEX_MODEL = 'gpt-4'
+        XAI_MODEL = 'grok-4.3'
         AI_REVIEW_FAIL_ON_FINDINGS = 'false'
     }
 
diff --git a/README.md b/README.md
index d3fb24f..ef14077 100644
--- a/README.md
+++ b/README.md
@@ -2,22 +2,26 @@
 
 ## Jenkins AI Review
 
-The Jenkins pipeline can run an OpenAI-powered review and report back to Gitea.
+The Jenkins pipeline can run an x.ai-powered review and report back to Gitea.
 
 Required Jenkins secrets and variables:
 
-- `OPENAI_API_KEY`
+- `XAI_API_KEY`
 - `GITEA_TOKEN`
 - `GITEA_URL`
 
 Optional variables:
 
-- `CODEX_MODEL`
+- `AI_REVIEW_MODEL`
+- `XAI_MODEL`
+- `XAI_BASE_URL`
 - `AI_REVIEW_FAIL_ON_FINDINGS`
 - `GITEA_REPO_OWNER`
 - `GITEA_REPO_NAME`
 - `GITEA_PR_NUMBER`
 
+The default review model is `grok-4.3`, using the OpenAI Python SDK against `https://api.x.ai/v1`.
+
 ## Build
 
 ```bash
diff --git a/scripts/ai_code_review.py b/scripts/ai_code_review.py
index fb395db..bb0cd9c 100644
--- a/scripts/ai_code_review.py
+++ b/scripts/ai_code_review.py
@@ -190,12 +190,19 @@ def request_review(diff_text: str) -> str:
             "The 'openai' package is not installed. Install it with 'pip install openai'."
         ) from exc
 
-    api_key = os.getenv("OPENAI_API_KEY")
+    api_key = os.getenv("XAI_API_KEY") or os.getenv("OPENAI_API_KEY")
     if not api_key:
-        raise RuntimeError("OPENAI_API_KEY is not set.")
+        raise RuntimeError("XAI_API_KEY is not set.")
 
-    model = os.getenv("CODEX_MODEL") or os.getenv("OPENAI_MODEL") or "gpt-4.1"
-    client = OpenAI(api_key=api_key)
+    model = (
+        os.getenv("AI_REVIEW_MODEL")
+        or os.getenv("XAI_MODEL")
+        or os.getenv("CODEX_MODEL")
+        or os.getenv("OPENAI_MODEL")
+        or "grok-4.3"
+    )
+    base_url = os.getenv("XAI_BASE_URL") or "https://api.x.ai/v1"
+    client = OpenAI(api_key=api_key, base_url=base_url)
 
     response = client.responses.create(
         model=model,