GPT-6 Astra vs Claude Opus 5
Astra is OpenAI's current flagship. Opus 5 is still the default coding model on this key, at half Astra's per-token rate. Reddit is full of Astra demos; the rate card is not a quality score.
Input / M (llmrelay): OpenAI list $10; Anthropic list $5. Half list on both.
Prices are llmrelay's, at 50% of official list. Specs are the vendor's own published figures (Anthropic model docs), not our benchmarks. We do not publish scores we cannot source.
Use GPT-6 Astra when
- +The task is computer use or Codex, not a single completion: browser, CRM, Sites, a tool loop that has to finish.
- +You already pay for ChatGPT Plus or Pro and want the same id on an API you control, at half OpenAI list.
- +Opus 5 gave a complete answer and you still want an OpenAI second pass before you ship.
Use Claude Opus 5 when
- +Everyday agentic coding. It is the current Claude default at $2.50/M input.
- +You are paying per task at any real volume. Astra at 2×, plus whatever extra tokens computer use emits, is the whole budget.
- +You do not need OpenAI-only surfaces. Switching later is one line on the same key.
The honest answer
Default to Opus 5. Pay Astra's 2× when the job is OpenAI computer use or when you have already watched Opus 5 miss. One prepaid key runs both, so the comparison is a prompt, not a migration.
What this costs you per month
At 50M input and 5M output tokens a month — a realistic heavy agent workload.
Struck-through column is the vendor's list price for the same traffic. Adjust the numbers on the calculator.
One key covers both
Switching between them is a model-id change, not a new account. Prepaid, no subscription, $10 minimum — enough to run the same prompt through both and settle the argument with your own output.
Next steps on this decision
Per-model detail for both sides, and the adjacent comparisons people usually read alongside this one.
- GPT-6 Astra pricing and specs$5.00/M in, $25.00/M out — half list. OpenAI’s current flagship. API, ChatGPT paid plans, half list here.
- Claude Opus 5 pricing and specs$2.50/M in, $12.50/M out — half list. Current flagship Opus. A generation past 4.8, same list price.
- Opus 5 vs Sonnet 5 for codingBoth are current-generation Claude models with a 1M context window.
- Fable 5 vs Opus 5 — is the flagship worth 2×?Fable 5 is the previous Fable snapshot, still sold at $5/$25 — twice Opus 5.
- Opus vs Sonnet for coding (measured)Measured on our own billing: $0.0152 against $0.0047 for one identical task.
- GPT-6 Astra vs Claude Fable 5.1Both are September 2026 flagships at $10/$50 list and $5/$25 here.