gcp-diagram

name: gcp-diagram description: Generate professional GCP-branded architecture diagrams using Gemini image generation models. Use when the user asks to create architecture diagrams, system diagrams, data flow diagrams, deployment diagrams, database schema diagrams, or any technical diagram styled like official Google Cloud Platform documentation. Also use when asked to visualize GCP architectures, agent systems, microservices, or service topologies. Supports gemini-3-pro-image-preview and gemini-2.5-flash-image models via Vertex AI.

GCP Architecture Diagram Generator

Generate publication-quality architecture diagrams styled like official Google Cloud Platform documentation using Gemini image generation.

Workflow

1. Gather Architecture Details

From user description or codebase, identify:

• Components and GCP services involved
• Connections, protocols, and data flow direction
• Logical groupings (which services belong together)
• Diagram type (system overview, agent hierarchy, data flow, schema, deployment, security)

2. Build the Prompt

Read references/gcp-brand.md for colors, typography, and icon guidelines. Select and fill a template from references/templates.md.

Every prompt must include these phrases:

• "professional, clean architecture diagram in the style of official Google Cloud Platform documentation"
• "GCP brand colors: blue (#4285F4), green (#34A853), yellow (#FBBC05), red (#EA4335)"
• "clean white background"
• "Google Cloud product icon style, clean lines, no 3D effects, no hexagons, modern flat design"
• "Google Cloud logo watermark at bottom left"

Color conventions by component type:

• Compute/Agents: Green (#34A853)
• Data/Analytics/BigQuery: Orange/Yellow (#F9AB00)
• AI/ML/Vertex AI: Purple (#A142F4)
• Storage/GCS: Yellow (#FBBC05)
• Networking/Serverless: Teal (#12B5CB)
• Security: Red (#EA4335)
• Discovery Engine/Search: Blue (#4285F4)
• Users/Clients: Red ellipse (#EA4335)
• Config/Infrastructure: Gray (#5F6368)

3. Generate

Try the PaperBanana MCP tool first (mcp__paperbanana__generate_diagram). If unavailable, use Vertex AI directly:

from google import genai
from google.genai import types

## gemini-3 requires global endpoint; gemini-2.5-flash-image uses us-central1
models = [
    ("gemini-3-pro-image-preview", "global"),
    ("gemini-2.5-flash-image", "us-central1"),
]
for model, location in models:
    try:
        client = genai.Client(vertexai=True, project=PROJECT_ID, location=location)
        response = client.models.generate_content(
            model=model,
            contents=prompt,
            config=types.GenerateContentConfig(response_modalities=["IMAGE", "TEXT"]),
        )
        for part in response.candidates[0].content.parts:
            if part.inline_data:
                with open(output_path, "wb") as f:
                    f.write(part.inline_data.data)
                break
        break
    except Exception:
        continue  # try fallback

Model priority: gemini-3-pro-image-preview (global endpoint) > gemini-2.5-flash-image (us-central1). Fall back automatically.

IMPORTANT: gemini-3-* models require location="global". Using a regional endpoint (e.g., us-central1) will return 404.

4. Overlay Official GCP Icons

Gemini image generation cannot accurately reproduce trademarked GCP product logos. After generating, replace the AI-approximated icons with official ones using scripts/overlay_icons.py.

113 official GCP product icons + 21 official GCP category icons are bundled in assets/icons/ (PNG, RGBA).

Category icons sourced from services.google.com/fh/files/misc/category-icons.zip. SVGs also available in assets/icons/categories/svg/.

Step-by-step

1. Read the generated diagram to identify GCP product icon locations (x, y coordinates)
2. Run the overlay script:

import sys
sys.path.insert(0, "<skill_dir>/scripts")
from overlay_icons import overlay_icons

overlay_icons("diagram.png", "diagram_final.png", [
    {"product": "BigQuery", "x": 400, "y": 200, "size": 48},
    {"product": "Vertex AI", "x": 200, "y": 100, "size": 48},
    {"product": "Cloud Run", "x": 600, "y": 300, "size": 48},
    {"product": "Cloud Storage", "x": 400, "y": 400, "size": 48},
])

Or via CLI:

python scripts/overlay_icons.py diagram.png diagram_final.png \
    --icons "BigQuery:400,200 Vertex\ AI:200,100 Cloud\ Run:600,300" --size 48

Finding coordinates

Open the generated diagram with Read tool to visually identify where each GCP product icon should be placed. Estimate x,y pixel coordinates for the center of each product icon box.

Available icon categories

Run python scripts/overlay_icons.py --list for the full mapping.

5. Verify Branding & Spelling (MANDATORY)

This step is required before delivering any diagram. Do NOT skip.

Branding Checklist

• Colors match GCP brand conventions from references/gcp-brand.md
  • Compute/Agents: Green (#34A853)
  • Data/Analytics: Orange/Yellow (#F9AB00)
  • AI/ML: Purple (#A142F4)
  • Storage: Yellow (#FBBC05)
  • Networking: Teal (#12B5CB)
  • Security: Red (#EA4335)
  • Search/Discovery Engine: Blue (#4285F4)
• Background is clean white (#FFFFFF)
• All shapes are rounded rectangles, circles, or ellipses — never hexagons
• No 3D effects, shadows, or gradients on service boxes
• Google Cloud logo watermark at bottom left
• Official GCP product icons overlaid via Step 4 (not AI-generated approximations)

Spelling Checklist

Read every label in the diagram and compare against official GCP product names:

• Every GCP service name matches official spelling (check table above)
• Every custom label (agent names, data store names, dataset names) is spelled correctly
• Acronyms are consistent (e.g., don't mix "BQ" and "BigQuery" in same diagram)
• Resource IDs and region names match actual deployed values

Layout & Readability

• All components labeled correctly
• Connections directional with protocols noted
• Text readable at expected display size
• Layout balanced, no overlapping elements

If any check fails, regenerate with a refined prompt. Do not deliver diagrams with branding or spelling errors.

Prompt Tips

• Specify layout: "top-to-bottom" or "left-to-right"
• Use shape hints: "rounded rectangle" (services), "cylinder" (databases), "ellipse" (users), "octagon" (security), "folder" (storage)
• Name every connection with its protocol
• Add "landscape orientation" for wide architectures
• Include resource IDs and regions for deployed resources
• Add "leave a blank square placeholder where each GCP product icon would go" to make overlay easier

References

• GCP brand colors, typography, icons: references/gcp-brand.md
• Prompt templates by diagram type: references/templates.md
• Official GCP icon assets (113 PNGs): assets/icons/ — bundled from the diagrams library
• Icon overlay script: scripts/overlay_icons.py
• GCP Product Icons PDF: https://services.google.com/fh/files/misc/google-cloud-product-icons.pdf
• GCP Icons Gallery: https://cloud.google.com/icons