Claude Sonnet 5 vs GPT-5.3-Codex for meeting notes
GPT-5.3-Codex wins, 91–87
Same 12 meeting notes tasks, marked blind by three rival labs. GPT-5.3-Codex took 4 tasks, Claude Sonnet 5 took 4, 4 tied. Tested 28 Aug 2026.
Where they differed most
Write the catch-up note for one named person. The meeting covered five items: the hosting migration (done, no action), Q3 headcount (two roles approved, one deferred), the outage post-mortem (actions on the infrastructure team), the rebrand timeline (slipping two weeks, marketing to confirm) and office parking (unresolved, nobody cares). The person who missed it is the marketing lead. Write their catch-up note. It must lead with what they personally now owe, keep what genuinely affects marketing, and cut what does not — a note that repeats all five items in order has failed the task. Use exactly 3 bullet points and no more. Under 120 words.
**Catch-up note for Sam (Marketing Lead)** - **Action on you:** Confirm the revised rebrand timeline — it's slipping two weeks, and we need your sign-off to update downstream comms/campaign dates. - **FYI, no action needed:** Hosting migration is done; Q3 headcount got two roles approved (one deferred) — neither touches your team. - **Skipped:** Outage post-mortem (infra's problem) and office parking (still unresolved, still nobody's priority) — not relevant to you, leaving out of this note. Ping me once you've confirmed the timeline shift.
**Maya, catch-up from today:** - **You owe:** please confirm the revised rebrand timeline (currently slipping by ~2 weeks) and send the updated milestone dates/owners to the group by tomorrow 3pm. - The slip will move downstream marketing work (campaign launch, asset freeze, and external comms timing), so flag any knock-on risks when you confirm. - No other actions for marketing came out of this meeting.
Task by task
| Task | Claude Sonnet 5 | GPT-5.3-Codex |
|---|---|---|
| The decision that was never made | 10 | 10 |
| Actions, owners, and the one with neither | 10 | 5 |
| The number said twice | 9 | 10 |
| Minutes for a meeting with a disagreement in it | 9 | 9 |
| Fourteen minutes, one sentence | 10 | 8 |
| Crosstalk | 10 | 9 |
| The musing that is not a commitment | 10 | 10 |
| The follow-up email nobody has to rewrite | 5 | 10 |
| Extract the dates, resolve the relatives | 10 | 10 |
| Who has not spoken | 9 | 10 |
| Notes for the person who missed it | 3 | 10 |
| The transcript is wrong | 9 | 8 |
Full receipts: Claude Sonnet 5, GPT-5.3-Codex · judges gemini-3.1-pro-preview, gpt-5.6-terra, grok-4.5
Questions people ask
Which is better for meeting notes: Claude Sonnet 5 or GPT-5.3-Codex?
GPT-5.3-Codex — it scored 91/100 against 87/100 on our 12-task meeting notes suite, winning 4 tasks to 4 with 4 tied. Every answer was marked blind by three judges from three rival AI labs.
How was this tested?
Both models answered the identical published meeting notes tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.
More meeting notes head-to-heads: GPT-5.3-Codex vs Grok 4.5 · Claude Sonnet 5 vs Grok 4.5 · GPT-5.3-Codex vs GPT-5.6 Sol · Claude Sonnet 5 vs GPT-5.6 Sol · GPT-5.3-Codex vs GPT-5.5 · Claude Sonnet 5 vs GPT-5.5
Full ranking: Best AI for meeting notes · model pages: Claude Sonnet 5, GPT-5.3-Codex