Add OpenRouter provider support

[AnkitParekh007]

---

title: "Add OpenRouter provider support"
labels: ["good first issue", "provider", "enhancement"]

Summary

Add an OpenRouter provider so users can access 100+ models (GPT-4, Claude, Llama, Mistral, Gemma, etc.) through a single unified API key.

Background

OpenRouter provides an OpenAI-compatible chat completions API that supports dozens of providers and models. Since devdocs-forge-agent already has an OpenAI provider using native fetch, OpenRouter support requires minimal changes — mainly just pointing at a different base URL and adding an HTTP-Referer header.

Files to Touch

File	Change
src/providers/openrouter.provider.ts	Create — implement Provider interface
src/providers/provider-registry.ts	Add 'openrouter' case
.env.example	Add OPENROUTER_API_KEY and OPENROUTER_MODEL
docs/PROVIDERS.md	Document OpenRouter setup
tests/provider-registry.test.ts	Add test case

Implementation Guide

OpenRouter uses the OpenAI chat completions format at https://openrouter.ai/api/v1/chat/completions.

Required headers:

• Authorization: Bearer ${OPENROUTER_API_KEY}
• HTTP-Referer: https://github.com/AnkitParekh007/devdocs-forge-agent
• X-Title: devdocs-forge-agent

The response format is identical to OpenAI: choices[0].message.content.

Acceptance Criteria

• DEVDOCS_PROVIDER=openrouter npm run generate -- --file ... works with a valid key
• OPENROUTER_API_KEY and OPENROUTER_MODEL read from environment
• Clear error message when key is missing (not a stack trace)
• docs/PROVIDERS.md updated with OpenRouter setup
• .env.example updated
• Tests updated

Difficulty

Low — ~60 lines, very similar to the OpenAI provider already in the codebase.

How to Get Started

git clone https://github.com/AnkitParekh007/devdocs-forge-agent.git
cd devdocs-forge-agent
npm install
# Look at src/providers/openai.provider.ts as a reference
npm test