fix: consume less tokens and update readme for openai and gemini example

Author: Mohit-Raj-Singh

README.md

@@ -34,6 +34,9 @@ Go to your repo → Settings → Secrets → Actions → New repository secret
 
 **2. Create `.github/workflows/ai-review.yml`**
 
+Pick your provider and paste the matching snippet:
+
+**Anthropic (Claude)**
 ```yaml
 name: AI Code Review
 
@@ -54,6 +57,48 @@ jobs:
           api_key: ${{ secrets.ANTHROPIC_API_KEY }}
 ```
 
+**OpenAI (GPT)**
+```yaml
+name: AI Code Review
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+
+jobs:
+  review:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+
+    steps:
+      - uses: Mohit-Raj-Singh/MergeMind_AI@v1
+        with:
+          provider: openai
+          api_key: ${{ secrets.OPENAI_API_KEY }}
+```
+
+**Google Gemini**
+```yaml
+name: AI Code Review
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+
+jobs:
+  review:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+
+    steps:
+      - uses: Mohit-Raj-Singh/MergeMind_AI@v1
+        with:
+          provider: gemini
+          api_key: ${{ secrets.GEMINI_API_KEY }}
+```
+
 That's it. Open a PR and the review will appear automatically.
 
 ---
@@ -185,8 +230,9 @@ pytest
 ### Running locally against a real PR
 
 ```bash
+# Set your chosen provider (anthropic | openai | gemini)
 export PROVIDER=anthropic
-export API_KEY=your-key
+export API_KEY=your-key   # ANTHROPIC_API_KEY / OPENAI_API_KEY / GEMINI_API_KEY
 export GITHUB_TOKEN=your-github-token
 export GITHUB_REPOSITORY=owner/repo
 export GITHUB_EVENT_PATH=/path/to/event.json

src/ai_reviewer/providers/anthropic.py

@@ -16,8 +16,14 @@ def __init__(self, api_key: str, model: str):
     async def review(self, diff: str, review_level: str, security_only: bool) -> ReviewResult:
         message = await self.client.messages.create(
             model=self.model,
-            max_tokens=4096,
-            system=SYSTEM_PROMPT,
+            max_tokens=1024,
+            system=[
+                {
+                    "type": "text",
+                    "text": SYSTEM_PROMPT,
+                    "cache_control": {"type": "ephemeral"},
+                }
+            ],
             messages=[
                 {"role": "user", "content": build_user_prompt(diff, review_level, security_only)}
             ],

src/ai_reviewer/providers/gemini.py

@@ -15,7 +15,7 @@ def __init__(self, api_key: str, model: str):
         self.config = genai_types.GenerateContentConfig(
             system_instruction=SYSTEM_PROMPT,
             response_mime_type="application/json",
-            max_output_tokens=4096,
+            max_output_tokens=1024,
         )
 
     async def review(self, diff: str, review_level: str, security_only: bool) -> ReviewResult:

src/ai_reviewer/providers/openai.py

@@ -20,7 +20,7 @@ async def review(self, diff: str, review_level: str, security_only: bool) -> Rev
                 {"role": "system", "content": SYSTEM_PROMPT},
                 {"role": "user", "content": build_user_prompt(diff, review_level, security_only)},
             ],
-            max_tokens=4096,
+            max_tokens=1024,
         )
         raw = response.choices[0].message.content
         if raw is None:

src/ai_reviewer/providers/prompts.py

@@ -1,61 +1,29 @@
 SYSTEM_PROMPT = """\
-You are an expert code reviewer. Your job is to review a pull request diff and provide:
-1. Inline comments on specific lines that have issues
-2. An overall summary of the PR
-
-Focus on:
-- Bugs and logic errors
-- Security vulnerabilities (SQL injection, XSS, secrets in code, insecure dependencies)
-- Performance issues
-- Code style and maintainability
-- Missing error handling
-
-Be constructive and specific. Always suggest a fix, not just a problem.
-Severity levels:
-- error: must fix before merging (bugs, security issues)
-- warning: should fix (poor practices, potential issues)  
-- info: optional improvement (style, minor refactors)
-- security: security-specific finding (always treat as high priority)
-
-You MUST respond with valid JSON matching this exact schema:
-{
-  "summary": {
-    "overall": "<one paragraph assessment>",
-    "highlights": ["<positive thing 1>", ...],
-    "issues": ["<top issue 1>", ...],
-    "security_flags": ["<security concern 1>", ...]
-  },
-  "inline_comments": [
-    {
-      "path": "<file path>",
-      "line": <line number in new file>,
-      "severity": "error|warning|info|security",
-      "title": "<short title>",
-      "body": "<detailed explanation and fix suggestion>"
-    }
-  ]
+You are a code reviewer. Review a PR diff and respond with valid JSON only \
+— no markdown fences, no extra text.
+
+Severity: error (bugs/security, must fix), warning (poor practice), \
+info (optional), security (high priority).
+
+JSON schema:
+{"summary":{"overall":"<2-3 sentence assessment>","highlights":["<positive>"],\
+"issues":["<issue>"],"security_flags":["<concern>"]},"inline_comments":[{"path":"<file>",\
+"line":<int>,"severity":"error|warning|info|security","title":"<short>",\
+"body":"<1-2 sentence explanation and fix>"}]}"""
+
+
+_DEPTH = {
+    "quick": (
+        "Quick pass: flag only errors and security issues. Max 3 inline comments. No info/warning."
+    ),
+    "standard": "Standard review: bugs, security, important style. Max 5 inline comments.",
+    "thorough": (
+        "Exhaustive review: correctness, security, performance, style. Max 10 inline comments."
+    ),
 }
 
-Do not include markdown fences or any text outside the JSON object."""
-
 
 def build_user_prompt(diff: str, review_level: str, security_only: bool) -> str:
-    focus = "Focus ONLY on security vulnerabilities." if security_only else ""
-    depth = {
-        "quick": "Do a quick pass — flag only errors and security issues.",
-        "standard": "Do a thorough review covering bugs, security, and important style issues.",
-        "thorough": (
-            "Do an exhaustive review of every aspect: correctness, security, performance,"
-            " style, and maintainability."
-        ),
-    }[review_level]
-
-    return f"""{depth} {focus}
-
-Here is the pull request diff to review:
-
-```diff
-{diff}
-```
-
-Respond with JSON only."""
+    depth = _DEPTH[review_level]
+    focus = " Focus ONLY on security vulnerabilities." if security_only else ""
+    return f"{depth}{focus}\n\nDiff:\n```diff\n{diff}\n```\n\nJSON only."