gemini

Original🇺🇸 English
Translated

Use Google Gemini API for text generation, multimodal analysis, image generation (Nano Banana), function calling, and search grounding. Invoke when user wants to use Gemini, ask Gemini, generate images with Gemini, or analyze content with Gemini.

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NPX Install

npx skill4agent add legacybridge-tech/claude-plugins gemini

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Gemini API

Use Google Gemini API via REST for text generation, multimodal analysis, image generation, and more.

Prerequisites

  • Environment variable
    GOOGLE_API_KEY
    must be set
  • API endpoint:
    https://generativelanguage.googleapis.com/v1beta

Available Models

ModelUse Case
gemini-2.5-flash
Fast text generation (default)
gemini-2.5-pro
High quality text generation
gemini-3-flash-preview
Latest flash model
gemini-3-pro-preview
Latest pro model
gemini-2.5-flash-image
Image generation (Nano Banana)
gemini-3-pro-image-preview
Advanced image generation with thinking & search

Workflow

Phase 1: Determine Task Type

Based on user request, identify which capability to use:
  • Text Generation: Basic prompts, chat, Q&A
  • Multimodal Analysis: Analyze images, videos, or audio
  • Image Generation: Create or edit images (Nano Banana)
  • Function Calling: Execute custom functions
  • Search Grounding: Real-time web search integration

Phase 2: Execute API Call

Use the appropriate curl command based on task type.

1. Text Generation

Basic Prompt

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts": [{"text": "Your prompt here"}]
      }]
    }'

With Configuration

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts": [{"text": "Your prompt here"}]
      }],
      "generationConfig": {
        "temperature": 0.9,
        "maxOutputTokens": 2000,
        "stopSequences": ["END"]
      }
    }'

Multi-turn Chat

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [
        {"role": "user", "parts": [{"text": "First message"}]},
        {"role": "model", "parts": [{"text": "Model response"}]},
        {"role": "user", "parts": [{"text": "Follow-up question"}]}
      ]
    }'

System Instructions

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "system_instruction": {
        "parts": [{"text": "You are a helpful assistant that speaks like a pirate."}]
      },
      "contents": [{
        "parts": [{"text": "Hello!"}]
      }]
    }'

JSON Mode Output

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts": [{"text": "List 3 colors as JSON array"}]
      }],
      "generationConfig": {
        "response_mime_type": "application/json"
      }
    }'

Streaming Response

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:streamGenerateContent?alt=sse&key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts": [{"text": "Write a long story"}]
      }]
    }'

Safety Settings

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts": [{"text": "Your prompt"}]
      }],
      "safetySettings": [
        {"category": "HARM_CATEGORY_DANGEROUS_CONTENT", "threshold": "BLOCK_ONLY_HIGH"},
        {"category": "HARM_CATEGORY_HARASSMENT", "threshold": "BLOCK_ONLY_HIGH"}
      ]
    }'

2. Multimodal Analysis

Image Analysis (Base64 Inline)

bash
# First encode image to base64
BASE64_IMAGE=$(base64 -w0 image.jpg)

curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts": [
          {"text": "Describe this image in detail"},
          {"inline_data": {"mime_type": "image/jpeg", "data": "'$BASE64_IMAGE'"}}
        ]
      }]
    }'

Video Analysis (File API)

Step 1: Upload Video

bash
# Get upload URL
UPLOAD_URL=$(curl -s "https://generativelanguage.googleapis.com/upload/v1beta/files?key=$GOOGLE_API_KEY" \
    -H "X-Goog-Upload-Protocol: resumable" \
    -H "X-Goog-Upload-Command: start" \
    -H "X-Goog-Upload-Header-Content-Length: $(stat -f%z video.mp4)" \
    -H "X-Goog-Upload-Header-Content-Type: video/mp4" \
    -H "Content-Type: application/json" \
    -d '{"file": {"display_name": "video.mp4"}}' \
    -D - | grep -i "x-goog-upload-url" | cut -d' ' -f2 | tr -d '\r')

# Upload file
curl "$UPLOAD_URL" \
    -H "X-Goog-Upload-Offset: 0" \
    -H "X-Goog-Upload-Command: upload, finalize" \
    -H "Content-Type: video/mp4" \
    --data-binary @video.mp4

Step 2: Query with Video

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts": [
          {"text": "Describe what happens in this video"},
          {"file_data": {"mime_type": "video/mp4", "file_uri": "FILE_URI_FROM_UPLOAD"}}
        ]
      }]
    }'

Audio Analysis

Similar to video, upload via File API then query:
bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts": [
          {"text": "Transcribe and summarize this audio"},
          {"file_data": {"mime_type": "audio/mp3", "file_uri": "FILE_URI_FROM_UPLOAD"}}
        ]
      }]
    }'

3. Image Generation (Nano Banana)

Basic Image Generation

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-image:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{"parts": [{"text": "Create a photorealistic image of a cat wearing a hat"}]}],
      "generationConfig": {
        "responseModalities": ["TEXT", "IMAGE"]
      }
    }'

With Aspect Ratio Control

Supported ratios:
1:1
,
2:3
,
3:2
,
3:4
,
4:3
,
4:5
,
5:4
,
9:16
,
16:9
,
21:9
bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-image:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{"parts": [{"text": "Create a landscape scene"}]}],
      "generationConfig": {
        "responseModalities": ["IMAGE"],
        "imageConfig": {
          "aspectRatio": "16:9"
        }
      }
    }'

Image Editing (Character Consistency)

bash
BASE64_IMAGE=$(base64 -w0 original.jpg)

curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-image:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts": [
          {"text": "Put this character in a tropical forest"},
          {"inline_data": {"mime_type": "image/jpeg", "data": "'$BASE64_IMAGE'"}}
        ]
      }],
      "generationConfig": {
        "responseModalities": ["TEXT", "IMAGE"]
      }
    }'

High Resolution (Pro Model - 2K/4K)

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-3-pro-image-preview:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{"parts": [{"text": "A photo of an oak tree in all four seasons"}]}],
      "generationConfig": {
        "responseModalities": ["TEXT", "IMAGE"],
        "imageConfig": {
          "aspectRatio": "1:1",
          "imageSize": "4K"
        }
      }
    }'

Image Generation with Search Grounding (Pro)

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-3-pro-image-preview:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{"parts": [{"text": "Visualize the current weather forecast for Tokyo as a chart"}]}],
      "generationConfig": {
        "responseModalities": ["TEXT", "IMAGE"],
        "imageConfig": {
          "aspectRatio": "16:9"
        }
      },
      "tools": [{"google_search": {}}]
    }'

Multi-Image Fusion

bash
BASE64_IMG1=$(base64 -w0 image1.jpg)
BASE64_IMG2=$(base64 -w0 image2.jpg)

curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-image:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts": [
          {"text": "Combine these two characters in a fantasy world"},
          {"inline_data": {"mime_type": "image/jpeg", "data": "'$BASE64_IMG1'"}},
          {"inline_data": {"mime_type": "image/jpeg", "data": "'$BASE64_IMG2'"}}
        ]
      }],
      "generationConfig": {
        "responseModalities": ["TEXT", "IMAGE"]
      }
    }'

4. Function Calling

Define and Call Functions

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "role": "user",
        "parts": [{"text": "What movies are playing in Mountain View?"}]
      }],
      "tools": [{
        "function_declarations": [{
          "name": "find_movies",
          "description": "Find movies playing in theaters",
          "parameters": {
            "type": "object",
            "properties": {
              "location": {"type": "string", "description": "City and state"},
              "genre": {"type": "string", "description": "Movie genre"}
            },
            "required": ["location"]
          }
        }]
      }]
    }'

Provide Function Response

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [
        {"role": "user", "parts": [{"text": "What movies are playing in Mountain View?"}]},
        {"role": "model", "parts": [{"functionCall": {"name": "find_movies", "args": {"location": "Mountain View, CA"}}}]},
        {"role": "function", "parts": [{"functionResponse": {"name": "find_movies", "response": {"movies": ["Barbie", "Oppenheimer"]}}}]}
      ],
      "tools": [{
        "function_declarations": [{
          "name": "find_movies",
          "description": "Find movies playing in theaters",
          "parameters": {
            "type": "object",
            "properties": {
              "location": {"type": "string"},
              "genre": {"type": "string"}
            },
            "required": ["location"]
          }
        }]
      }]
    }'

5. Search Grounding

Real-time web search integration:
bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{"parts": [{"text": "What is the current Google stock price?"}]}],
      "tools": [{"google_search": {}}]
    }'
Response includes
groundingMetadata
with sources.

6. Context Caching

For repeated queries on the same large content:

Create Cache

bash
curl "https://generativelanguage.googleapis.com/v1beta/cachedContents?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "model": "models/gemini-2.5-flash",
      "contents": [{"parts": [{"text": "LARGE_DOCUMENT_TEXT_HERE"}]}],
      "ttl": "3600s"
    }'

Use Cache

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "cachedContent": "cachedContents/CACHE_ID",
      "contents": [{"parts": [{"text": "Summarize the document"}]}]
    }'

7. Model Information

List All Models

bash
curl "https://generativelanguage.googleapis.com/v1beta/models?key=$GOOGLE_API_KEY"

Get Specific Model

bash
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash?key=$GOOGLE_API_KEY"

Response Handling

Text Response Structure

json
{
  "candidates": [{
    "content": {
      "parts": [{"text": "Response text here"}],
      "role": "model"
    },
    "finishReason": "STOP"
  }],
  "usageMetadata": {
    "promptTokenCount": 10,
    "candidatesTokenCount": 50,
    "totalTokenCount": 60
  }
}

Image Response Structure

When using image generation, response includes base64-encoded images:
json
{
  "candidates": [{
    "content": {
      "parts": [
        {"text": "Here is your image:"},
        {"inlineData": {"mimeType": "image/png", "data": "BASE64_IMAGE_DATA"}}
      ]
    }
  }]
}
To save the image:
bash
# Extract and decode image from response
echo "BASE64_DATA" | base64 -d > output.png

Error Handling

ErrorCauseSolution
400Invalid requestCheck JSON syntax
401Invalid API keyVerify GOOGLE_API_KEY
429Rate limitWait and retry
500Server errorRetry with exponential backoff

Best Practices

  1. Use appropriate model: Flash for speed, Pro for quality
  2. Set temperature: Lower (0.1-0.3) for factual, higher (0.7-1.0) for creative
  3. Limit output tokens: Set
    maxOutputTokens
    to avoid excessive responses
  4. Use caching: For repeated queries on large documents
  5. Handle streaming: For long responses, use
    streamGenerateContent
  6. Image generation tips: Use detailed, descriptive prompts for best results