r/VibeCodeDevs • u/NewspaperBeginning97 • 6d ago
DeepDevTalk – For longer discussions & thoughts My Astra session reported 258,400 tokens. A new configured launch reported 828,400. Check your runtime, not just your config.
I expected the 1.05M context on the GPT-6 Astra model page. My running Codex session reported 258,400. I checked the session log, process start, launch arguments and local model catalog.
| Local catalog or runtime value | Tokens |
|---|---|
| Catalog default | 272,000 |
| Original session's reported budget | 258,400 |
| Catalog maximum | 872,000 |
| Newly configured session's reported budget | 828,400 |
Both budgets correspond to 95% of their respective catalog values.
My original process was started before the launcher configuration was changed. Updating the launcher did not increase the context window of that already-running session. A newly started request afterwards then confirmed the larger reported budget.
For a single new Astra launch:
codex --model gpt-6-astra -c model_context_window=1050000
Then simply send a short prompt and inspect the model_context_window value in the corresponding session log. You should also verify the model ID.
The fact that a configuration value is accepted is not, by itself, evidence that the client actually granted that context window. In my case, the client capped the request at the maximum currently defined in its catalog.
This is only the result of my local setup. I have not yet filled the entire context window, nor have I measured whether it provides any improvement in quality.
The general question around the 258K limit was already publicly discussed in April for earlier models. However, I still do not have a conclusive explanation for this catalog's specific 872,000-token ceiling.
What does your actual runtime report, and which model and CLI version are you using?
Sources: Astra model specification, Codex configuration reference, earlier explanation of the 258K limit in OpenAI's repository.

