codex

Facts

Openness

Open source

Licence

Apache-2.0

Language

Rust

Pinned version

a956835 (2026-10-01)

Topics checked

32 of 33

Kind of agent

Coding

Source repository (opens another site)

What it does notably well

• Budgets

  Goal budget exhaustion marks the goal budget_limited and injects a steering message once per goal telling the model to stop substantive work and leave a clear next step, rather…

  One RolloutBudget counter is shared across a whole root thread tree and fed by server-reported budget units when present, so spawned agents cannot escape the limit.

• Code mode

  The model catalog, not a user flag, selects the tool mode: tool_mode code_mode_only on 10 of 11 bundled models makes exec and wait the only model-visible tools, overriding the…

  Fail-closed exclusive mode: with no host process the model gets an error and the code never runs in the harness process.

  Yielding cells: exec and wait return after 10,000 ms with the program still alive, so a long program does not block the turn and the model can wait, poll or terminate.

• Compaction

  With provider openai and API-key sign-in (bundled catalog, token_budget off), compaction is a Responses-API round trip that returns an encrypted Compaction item; beside it the…