Review

/tml:review — did it work, and what did it cost

Adversarial by construction. The default posture is that the change did not do what it claims, and the review's job is to find out whether that default survives contact with the diff.

Hard rules

1. Read-only. No edits, no writes, not even to ./.tml/. Verdicts only.
2. Three questions, always, in order: did the mechanism engage, is the measurement still valid, what did it silently break.
3. "Improved throughput" is not an answer to any of them.
4. A verdict without a check behind it is an opinion. Name the file, the line, the trace, or the number.

Procedure

1. What is claimed, and what would falsify it

State the claim in one sentence, then its radius (references/evidence-grades.md §3.1) read mechanically off the diff, then what observation would show it false. If nothing would, say so — an unfalsifiable claim is the finding.

2. Did the mechanism engage

The most common failure is a change that is present in the source and inert at runtime:

• A flag set after the object it configures was constructed.
• A fast path guarded by a condition that never holds — dtype, shape, contiguity, device, or a version check.
• A compiled path recompiling every step (count the recompilations; a recompilation per step is worse than no compilation).
• A kernel that silently fell back because its workspace did not fit — which is also why an interior batch-size optimum can appear (tier-b-systems.md B14).
• An optimiser change where the beta convention differs between algorithms: Adan's β₂ is not Adam's β₂, Adan's β₃ is, RMSProp's alpha is, and PyTorch's SGD momentum decays a sum rather than an average (references/optimisers.md §1). A ported beta value is a silent learning-rate change. Check this whenever an optimiser was swapped or its hyperparameters were copied from elsewhere.
• Weight decay carried across an Adam → AdamW boundary unchanged — different hyperparameter, different scale (optimisers.md §2).

3. Is the measurement still valid

references/tier-c-protocol.md and references/pitfalls.md:

• Score inflation — did the change alter what is being measured, not just how fast it is computed? Evaluation set, metric definition, checkpoint selection rule, or the harness itself.
• Stale step-unit hyperparameters — anything expressed in steps (schedules, warmup, decay length, EMA horizons, eval cadence) after a batch-size or throughput change. references/optimisers.md §1.3: a horizon fixed in steps shrinks in examples when the batch grows.
• Timing boundary — is evaluation inside or outside the clock? Warmup amortised or included? One-time costs priced at the real k?
• Baseline drift — is the comparison still against the same baseline, run on the same harness, on the same hardware?

4. What did it silently break

• Quality dimensions other than the mean — calibration, worst-group, tails, robustness under shift, determinism. A mean that held while calibration moved is a real regression and a common one.
• Train/eval mismatch — a transform, a precision, or a normalisation applied on one path and not the other.
• Leakage — validation data touching training, directly or through statistics.
• Numerics — reductions moved to lower precision; fp16 without loss scaling where it is needed; catastrophic cancellation in a difference of near-equal quantities (optimisers.md §3.1 for the Adan case in bf16).
• Legibility — the axis nobody records. A pipeline only one person can now modify is frequently a net loss (tier-c-protocol.md).

5. Verdict

One of:

• holds — mechanism engaged, measurement valid, no unpriced breakage. Say what evidence supports each of the three.
• holds with caveats — plus the specific caveats.
• does not hold — with the specific reason and the check that shows it.
• cannot determine — with the specific missing measurement, and what to run.

Then the residue: what remains unverified and would need a measurement to close.

Handoffs

• The change is fine but the sweep behind it is questionable → /tml:analyze.
• The review found instability rather than a bad change → references/instability.md.

Completion status

DONE (all three questions answered with evidence), DONE_WITH_CONCERNS, BLOCKED, or NEEDS_CONTEXT.