<h2>Why?</h2>
When Claude Code Opus 4.5 works alone it misses things.
When Gemini 3 Pro works alone it misses things.
But when Claude Code asks Gemini critics about highly technical decisions they suddenly get 10x smarter. It’s like teleporting in 2028.
<h2>How?</h2>
There are 2 ways to connect Claude Code with Gemini:
<ul>
<li>MCP server</li>
<li>Claude Code Agent</li>
</ul>
Sadly there is no official MCP server for Gemini and I didn’t find a serious up-to-date Github repo providing it.
So we gonna use the safe Claude Code agent way:
<ol>
<li>Create a bash script that calls the Google Gemini API</li>
<li>Create a Claude Code agent that generate proper prompt for Gemini and execs the bash script</li>
</ol>
We can then prompt Claude Code with <code>ask gemini critics about this plan</code> and it will significantly improve your work, and often save you from unseen edge-cases.
<h2>The code</h2>
The following files should be stored in your project root folder in:
<pre><code>.claude/
 agents/
 gemini.md
 scripts/
 gemini.sh
</code></pre>
<h2>The bash script</h2>
Stored in <code>.claude/scripts/gemini.sh</code>.
Make it executable with: <code>chmod +x gemini.sh</code>.
And store your GEMINI_API_KEY in your bash/zsh profile.
<pre><code class="language-bash">#!/bin/bash
# Gemini API script for Claude Code agents
# Usage: ./gemini.sh &quot;Your prompt here&quot;
# Requires: GEMINI_API_KEY environment variable

set -e

MODEL=&quot;gemini-3-pro-preview&quot;
API_URL=&quot;https://generativelanguage.googleapis.com/v1beta/models/${MODEL}:generateContent&quot;

if [ -z &quot;$GEMINI_API_KEY&quot; ]; then
 echo &quot;Error: GEMINI_API_KEY environment variable is not set&quot; &gt;&amp;2
 exit 1
fi

if [ -z &quot;$1&quot; ]; then
 echo &quot;Usage: $0 \&quot;Your prompt here\&quot;&quot; &gt;&amp;2
 exit 1
fi

PROMPT=&quot;$1&quot;

response=$(curl -s &quot;${API_URL}?key=${GEMINI_API_KEY}&quot; \
 -H &quot;Content-Type: application/json&quot; \
 -d &quot;{
 \&quot;contents\&quot;: [{
 \&quot;parts\&quot;: [{
 \&quot;text\&quot;: $(echo &quot;$PROMPT&quot; | jq -Rs .)
 }]
 }],
 \&quot;generationConfig\&quot;: {
 \&quot;temperature\&quot;: 0.7,
 \&quot;maxOutputTokens\&quot;: 8192
 }
 }&quot;)

# Check for errors
error=$(echo &quot;$response&quot; | jq -r &#x27;.error.message // empty&#x27;)
if [ -n &quot;$error&quot; ]; then
 echo &quot;API Error: $error&quot; &gt;&amp;2
 exit 1
fi

# Extract and print the response text
echo &quot;$response&quot; | jq -r &#x27;.candidates[0].content.parts[0].text // &quot;No response&quot;&#x27;
</code></pre>
<h2>The Claude Code agent</h2>
Stored in <code>.claude/agents/gemini.md</code>. Feel free to tweak the instructions there:
<pre><code class="language-md">---
name: gemini
description: Consults Gemini 3 Pro for a second opinion on code, architecture, or technical questions
tools:
 - Bash
 - Read
 - Glob
 - Grep
---

You are a Gemini consultant agent. When the user asks you to consult Gemini, get a second opinion, or compare perspectives:

1. Read any relevant code or context the user is asking about
2. Formulate a clear prompt for Gemini
3. Call the Gemini API using the script:

.claude/scripts/gemini.sh &quot;Your prompt here&quot;


4. Summarize Gemini&#x27;s response and present it to the user

Tips:
- For code review, include the actual code in your prompt
- Be specific in your prompts to get useful responses
- Compare Gemini&#x27;s perspective with your own analysis when relevant
</code></pre>

Pierre

Claude Code Opus 4.5 and Gemini 3 Pro each miss things when working independently, but combining them improves decision-making significantly. This guide shows how to integrate Gemini into Claude Code using a bash script that calls the Gemini API and a Claude Code agent that formats prompts and executes the script. The setup involves creating two files in your project's `.claude/` directory: a bash script for API calls and an agent definition that handles consultation requests.

Make Claude Code Opus talk to Gemini Pro

Thanks for sharing.
There also is llm counsil plugin you might wanna take a look at