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adminandGitHub 1215b5044c Remove retired Gemini fallback models (#8199)
* Remove retired Gemini fallback models

* Prefer cheaper Gemini fallbacks first
2026-06-26 07:46:55 -07:00

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LLM Model Comparison

This document compares streaming latency (time-to-first-token) and pricing across OpenAI, Anthropic (Claude), and Google (Gemini) models for use in Eagle's narrative text generation.

Test Methodology

All tests were performed locally using curl with streaming enabled. Each model was tested 3 times with the same prompt:

"Write a short paragraph about a brave knight who discovers a hidden cave. Make it vivid and descriptive."

Time-to-first-token (TTFT) was measured from request initiation to the first text content appearing in the stream.

Streaming Latency Results (January 2026)

Model Run 1 Run 2 Run 3 Average TTFT
Gemini 2.5 Flash-Lite 0.76s 0.54s 0.53s ~0.6s
gpt-4.1-mini 1.65s 1.72s 1.68s ~1.7s
claude-3-5-haiku 1.85s 1.92s 1.88s ~1.9s
gpt-5.2 3.25s 3.38s 3.32s ~3.3s
gpt-5-mini 2.52s 5.82s 3.12s ~3.8s (high variance)
Gemini 3 Flash Preview 4.11s 4.77s 4.28s ~4.4s
claude-sonnet-4 4.89s 5.12s 4.98s ~5.0s
Gemini 2.5 Flash 5.60s 7.00s 7.79s ~6.8s

Pricing Comparison (per 1M tokens)

Model Input Price Output Price Notes
Gemini 2.5 Flash-Lite $0.10 $0.40 Cheapest and fastest
Gemini 2.5 Flash $0.15 $0.60
gpt-5-mini $0.25 $2.00
gpt-4.1-mini $0.40 $1.60 Best OpenAI value
Gemini 3 Flash Preview $0.50 $3.00 Includes thinking tokens
claude-3-5-haiku $0.80 $4.00 Best Anthropic value
gpt-5.2 ~$1.00 ~$10.00 Full reasoning model
Gemini 2.5 Pro $1.25 $10.00
Gemini 3 Pro Preview $2.00 $12.00 ≤200K context
claude-sonnet-4 $3.00 $15.00

Recommendations

For Narrative Text Generation (Default)

Gemini 3.1 Flash-Lite is recommended as the default:

  • Priced at $0.25/$1.50 per 1M input/output tokens
  • Significantly faster than 2.5 Flash-Lite on throughput and TTFT
  • Meaningfully smarter than 2.5 Flash-Lite, while remaining one of the cheapest options
  • Quality is more than sufficient for short narrative snippets

Alternative Options

Priority Model When to Use
Speed + Cost Gemini 3.1 Flash-Lite Default for most use cases
Speed + Quality gpt-4.1-mini When you need OpenAI quality with good speed
Instruction Following claude-3-5-haiku Complex multi-step prompts, consistent tone
Maximum Quality claude-sonnet-4 or gpt-5.2 When output quality is paramount

Quality Trade-offs

For short narrative snippets (1-3 paragraphs):

  • Flash-Lite vs Haiku/4.1-mini: Minor quality difference, significant speed gain
  • Haiku vs Sonnet: Noticeable quality difference in creative writing variety
  • gpt-4.1-mini vs gpt-5.2: Moderate quality difference, significant cost savings

Configuration

LLM settings can be changed at runtime via the admin console:

  1. Navigate to Admin Console → Settings
  2. Change LlmProvider to select vendor (gemini, openai, claude)
  3. Change the corresponding model name setting:
    • GeminiModelName (default: gemini-3.1-flash-lite)
    • OpenAiModelName (default: gpt-4.1-mini)
    • ClaudeModelName (default: claude-3-5-haiku-20241022)

Changes take effect on the next LLM request.

Environment Variables

For production deployment, ensure API keys are set:

OPENAI_API_KEY=sk-...
ANTHROPIC_API_KEY=sk-ant-...
GEMINI_API_KEY=AIza...

Notes

  • gpt-5-mini showed high latency variance (2.5s - 5.8s) in testing
  • Gemini 2.5 Flash was surprisingly slower than Flash-Lite, possibly due to internal reasoning overhead
  • Gemini 3 Flash is a frontier model with better quality but higher latency than 2.5 Flash-Lite
  • All Gemini models have a generous free tier (up to 1,000 daily requests)