Choose an AI model for coding agents in 2026
Compare DeepSeek V4.1 Flash, GPT-6 Astra, Claude Fable 5.1 and Gemini 3.8 Flash by failure cost, context, multimodal input, API economics and benchmark evidence.
On this page
Filter by input type, context and budget, then check the results on your own task. This page collects recorded specifications, prices and analyses. Public benchmark scores do not guarantee the same performance in your project.
Filter by the task, then verify the result
Compare total cost per accepted task
Use the same task to record input, output, cache and retry costs. A lower token price does not guarantee a lower total cost after rework.
Use a real problem and fixed tests
Choose a known problem, limit the change scope and fix the test command. Inspect the final changes and keep human review for security or production work.
Check completion and recovery
Record completion, interruptions, retries and time spent taking over manually. Context-window size alone does not show reliable execution.
Check the actual input path
A model accepting an input type does not prove that the configured DSH endpoint or tools support it. Confirm with a non-sensitive sample.
Keep the same starting point
Give each model an independent project copy, a new session, the same prompt and the same acceptance checks.
September 11, 2026 specification and price snapshot
The table records a historical snapshot, not a current quote. It shows DeepSeek peak rates; the recorded off-peak rates were half-price. Gemini listed launch rates of $0.75/$3.75 and regular rates of $1.50/$7.50. Astra listed a separate long-context rule above 272K input tokens. Check provider pages for current prices, cache charges and tool fees.
| Model | Context | Max output | Input / 1M | Output / 1M | Evidence boundary |
|---|---|---|---|---|---|
| DeepSeek V4.1 Flash | 1M | 384K | $0.30 peak | $1.20 peak | Keep provider tests separate from independent tests; V4 Pro scores are not V4.1 Flash scores |
| GPT-6 Astra | 1.05M | 128K | $10 | $50 | Check reasoning effort, tool environment and task version before comparing scores |
| Claude Fable 5.1 | 1M | 128K | $10 | $50 | For long tasks, also check interruptions, recovery, retries and manual rework |
| Gemini 3.8 Flash | 1M | 64K | $0.75 launch | $3.75 launch | Check endpoint support for the required input; launch and regular prices differ |
Check whether public scores can be compared
- Use official model pages for context, modalities, output limits and provider pricing.
- Label provider-run benchmarks as provider evidence instead of presenting them as independent rankings.
- Compare independent scores only when the exact model version, benchmark revision, harness and reasoning effort are known.
- Do not reuse DeepSeek V4 Pro scores as DeepSeek V4.1 Flash scores. A provider's statement about relative performance does not create a same-version independent result.
- Track retries, tool loops and human review alongside token spend. Raw price is not accepted-task cost.
Open the analysis that matches the decision
DeepSeek
Frontier routing
Cost and evidence
Primary and independent sources
These links accompany the September 11, 2026 snapshot. Prices, aliases and evaluation methods may have changed; this page does not claim a fresh verification. Recheck the provider pages before a large production commitment.
DeepSeek API — Models & Pricing, OpenAI API — GPT-6 Astra, Claude Platform — Claude Fable 5.1, Google DeepMind — Gemini 3.8 Flash model card, Artificial Analysis — current model comparisons
Model setup, selection and cost guides
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