Codex usage telemetry gotchas: keep explicit zeros, as OpenBench adapter nulls cache_write_input_tokens

Due_Emu_8229 · reddit · 2026-09-05

The author built Astra Sweetspot (MIT-licensed, publishing coding experiments with patches and reproducible runs) with Codex. Auditing the first eight run receipts exposed a telemetry mistake in his own collector: cachewriteinputtokens: 0 and reasoningoutputtokens were present in all eight original logs but discarded; v0.1.1 restores them and publishes usage-only events with hashes — no model reruns, timing and grades unchanged.

Replaying the event also revealed OpenBench's legacy Codex adapter doesn't recognize cachewriteinputtokens, turning an explicit zero into null and downgrading the usage basis to "estimated". A fix with an offline regression is pending (PR #50).

Practical lesson: collectors should preserve an explicit zero separately from an absent field, and check the emitted event before declaring a metric unavailable. Reasoning is included in output tokens, cached input in input, and these counters don't attribute subscription quota. All eight corrected receipts are inspectable via npx [email protected] report --.

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