Replace Claude with Gemini 3.1 Pro

[heisninja]

Overview

This pull request migrates Fabricate from Anthropic's Claude to Google's Gemini 3.1 Pro for code generation while keeping all other functionality identical.

Changes Made

1. Dependencies (requirements.txt)

• Removed: anthropic>=0.39.0
• Added: google-generativeai>=0.8.0

2. Code Generator (fabricate/generator.py)

• Replaced import anthropic with import google.generativeai as genai
• Updated class docstring from "using Claude" to "using Gemini 3.1 Pro"
• Changed initialization:
  • From: self.client = anthropic.Anthropic(api_key=api_key)
  • To: genai.configure(api_key=api_key) and self.client = genai.GenerativeModel(model)
• Renamed method _call_claude() to _call_gemini()
• Updated Gemini API call to use generate_content() with GenerationConfig
• Default model: gemini-3.1-pro-preview
• Kept JSON extraction logic and fallback mechanisms unchanged

3. Configuration (fabricate/config.py)

• Changed field name: anthropic_api_key → gemini_api_key
• Updated field description to reference Google Gemini
• Kept all other configuration unchanged

4. CLI (fabricate/cli.py)

• Renamed option: --anthropic-key → --gemini-key (short form -g)
• Updated environment variable: FABRICATE_ANTHROPIC_API_KEY → FABRICATE_GEMINI_API_KEY
• Updated error messages to reference Gemini API key
• Updated parameter name in function calls from anthropic_api_key to gemini_api_key

5. Persona Fabricator (fabricate/persona.py)

• Updated parameter name: anthropic_api_key → gemini_api_key in PersonaFabricator.__init__()
• Updated run_fabrication() function signature to use gemini_api_key
• Updated docstrings to reference Google Gemini

Behavior

✅ Repository concept generation
✅ Initial commit generation
✅ Subsequent commit generation
✅ Commit history generation and backdating
✅ GitHub repository creation and pushing
✅ All fallback mechanisms
✅ Output formatting and JSON handling

Testing

Users should set the environment variable and run:

export FABRICATE_GEMINI_API_KEY="your-gemini-api-key"
export FABRICATE_GITHUB_TOKEN="your-github-token"
fabricate generate -l python -r 2

Or use the command-line option:

fabricate generate --gemini-key your-key --github-token your-token -l python -r 2

Notes

• The Gemini API requires the generation config to be explicitly set for max tokens and temperature
• All prompt structures remain identical - only the API integration changed
• Fallback mechanisms ensure graceful degradation if API calls fail
• The model can be customized via the model parameter (defaults to gemini-3.1-pro-preview)

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[devin-ai-integration]

Devin Review found 1 potential issue.

View 4 additional findings in Devin Review.

[devin-ai-integration]

🔴 pyproject.toml still declares anthropic dependency instead of google-generativeai

The migration from Anthropic to Gemini updated requirements.txt (line 1) but did not update pyproject.toml:27, which still declares "anthropic>=0.39.0" as a dependency. Since pyproject.toml is the authoritative dependency specification used by pip install ., pip install -e ., and package builds, anyone installing the package via the standard Python packaging flow will get anthropic installed but not google-generativeai. This causes an immediate ModuleNotFoundError at runtime when import google.generativeai as genai executes in fabricate/generator.py:10.

Prompt for agents

In pyproject.toml, line 27, change the dependency from "anthropic>=0.39.0" to "google-generativeai>=0.8.0" to match the requirements.txt update and the actual import used in fabricate/generator.py.

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