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Codex Astra: Cross-Window Memory Compression Arrives
OpenAI rolled out an experimental compaction feature dubbed Astra in Codex for GPT-6, persisting notes across context windows. Community disclosures and follow-up coverage tracked the rollout in early September.
2026-09-04 ~ 2026-09-07 · 2 episodes · 9 posts
Episode 1 · OpenAI ships experimental compaction for GPT-6 Astra in Codex: notes persist across context windows (2026-09-04, 5 posts)
On September 5, danielmac8 disclosed that OpenAI shipped a new compaction mechanism for GPT-6 Astra in Codex. It is experimental, off by default, and must be enabled manually. Once enabled, the model can save key information as "notes" that persist across context windows instead of being lost with old ones; earlier context windows, including messages and tool-call records, also become searchable rather than being repeatedly compressed into a single summary. danielmac8 argues this stops the model from behaving like an amnesiac.
Confirmed
- The feature is live in Codex, experimental, off by default, and requires manual enabling (m2/m3/m4)
- Two core capabilities: notes saved across context windows; earlier context (messages and tool calls) becomes searchable (m2/m3/m4)
- The goal is to stop information from being lost through repeated compression once the context window fills up (m2/m5)
Why it matters
- VraserX (m5) calls it Astra's most important yet least flashy feature: seemingly plumbing-level work, but a key step toward letting long-running agents accumulate state over time
- Persistent cross-window memory means long-task agents no longer "forget," which matters for complex multi-step workflows
- GPT-6 Astra's quiet superpower: persistent notes and searchable context across windows — VraserX · 2026-09-04
- GPT-6 Astra's Codex compaction: persistent notes and searchable past contexts — daniel_mac8 · 2026-09-05
- GPT-6 Astra ships compaction in Codex: notes persist and old context stays searchable — daniel_mac8 · 2026-09-05
- GPT-6 Astra's experimental compaction in Codex saves notes across context windows, off by default — TheMoonMidas · 2026-09-05
- Codex launches Astra: notes that persist across context windows — gabrielchua · 2026-09-05
Episode 2 · Codex's Astra Keeps Notes Across Context Windows and Makes History Searchable (2026-09-05, 4 posts)
OpenAI's experimental Astra feature for Codex persists notes across context windows and makes earlier messages and tool outputs searchable, replacing lossy repeated summarization for long tasks and reportedly saving significant credits.
- Codex's experimental context management replaces compression with notes + searchable history, slashing usage — EAccelerate_42 · 2026-09-05
- Codex Astra adds cross-context note persistence to fight context bloat in long tasks — dair_ai · 2026-09-06
- Codex launches Astra: notes persist across context windows without lossy summaries — CShorten30 · 2026-09-06
- Codex adds experimental cross-context memory: notes and history search via config flag — reach_vb · 2026-09-07