# Protocol amendment v1.10: outcome-unblinded termination of the exploratory model arm

Issued on 2026-08-09 after seven of the 36 frozen model-arm episodes had
completed. This is an outcome-unblinded operational termination. It does not
alter the confirmatory mutation experiment, its estimands, its denominators,
or any previously opened result.

## Observed state at the decision

- Seven episodes were complete: four tau2 and three AppWorld; no ToolSandbox
  model episode had completed.
- Three episodes received official acceptance. In all three, the generated
  persistent state exactly matched the known-valid state under global-exact,
  task-projected, and delta-complete reference rules.
- Four episodes were rejected. All four left the task-relevant persistent
  state unchanged.
- No completed episode contained an observed harmful side effect, and no
  episode satisfied RQ5's conflict condition of official acceptance with
  delta-complete rejection.
- The seven episodes consumed 355,381 combined agent and fixed-simulator
  tokens. No credential value was logged.

## Decision and reason

The remaining 29 episodes are not run. The secondary arm was intended only to
check whether naturally generated trajectories could reach blind spots found
by the deterministic mutation study. At this checkpoint it primarily measured
task completion and interface adherence. Continuing would require at least 17
more completed episodes to reach the predeclared 24/36 manuscript-inclusion
threshold, while adding provider identity, benchmark-interface, and agent
success confounds to a paper whose confirmatory unit is the evaluator.

The termination is based on expected decision value and manuscript focus, not
on a claim that the zero observed conflicts estimates a zero population rate.
The sample is too small and uneven for that inference. The API balance was not
exhausted.

## Reporting consequences

1. All seven completed episodes, the pre-generation DeepSeek infrastructure
   error, and the earlier gateway records remain append-only.
2. RQ5 does not meet its predeclared inclusion threshold and cannot appear as
   a confirmatory or provider-comparison result.
3. A stopped-arm aggregate may be reported in a protocol-deviation appendix or
   replication artifact. It must be labeled incomplete and outcome-unblinded.
4. The four rejected episodes cannot be removed, replaced, or rerun with a
   changed prompt or step budget.
5. The main mutation experiment remains the sole basis for the paper's
   evaluator-sensitivity conclusions and retains zero model/API calls and zero
   paid API cost.

