What causes "optimizer %q not found in trial %s" in JuliusBrussee/caveman?

List the trial plan's moves (e.g. the trial report/plan command) and copy an exact OptimizerID

optimizer not found in trial

Error message

optimizer %q not found in trial %s

What it means

promoteMove (proxy/cmd/caveman-proxy/main.go:945) searches the trial plan's Moves for an entry whose OptimizerID matches the requested optimizer. If no move matches, the zero-value move has an empty OptimizerID and the command aborts with this error. It means the optimizer id does not exist in the given trial's plan — a lookup failure, not a state problem.

Solutions

List the trial plan's moves (e.g. the trial report/plan command) and copy an exact OptimizerID
Double-check --trial-id points at the trial that actually contains this optimizer
Re-run the trial plan build if the plan was regenerated and the id no longer exists
Check for typos/case differences in the optimizer identifier

Example fix

// before
caveman-proxy trial promote --trial-id 2026-09-20-a --optimizer compress-0pt
// after (id that exists in the plan)
caveman-proxy trial promote --trial-id 2026-09-20-a --optimizer context-compress.v1

Defensive patterns

Strategy: validation

Validate before calling

plan, err := store.LoadTrialPlan(home, trialID)
if err != nil { return err }
found := false
for _, m := range plan.Moves {
    if m.OptimizerID == optimizerID { found = true; break }
}
if !found {
    return fmt.Errorf("optimizer %q not in trial %s; available: %v", optimizerID, trialID, idsOf(plan.Moves))
}

Prevention

Copy optimizer ids from the trial plan output verbatim instead of retyping
Confirm --trial-id matches the trial that produced the optimizer
Keep the trial plan report open when promoting moves
Watch for regenerated plans changing optimizer ids

When it happens

Trigger: Calling the trial promote flow (runTrial → promoteMove) with --optimizer <id> where <id> is not one of the OptimizerID values in the stored TrialPlan for the supplied --trial-id.

Common situations: Typo or casing mismatch in the optimizer id; referencing an optimizer from a different trial's plan; the trial plan was regenerated and the optimizer id changed; stale docs listing an old optimizer id.

Understand the failure class

Background: "Not found" and "does not exist" errors: why "Task not found", "No such folder", and "Can't find" fire when a lookup comes back empty — this error's family across 14 libraries.

Related errors

AI-assisted analysis of JuliusBrussee/caveman@3ee70a1026 (2026-09-20). Data as JSON: /api/errors/14312572bcd89160. Report an issue: GitHub.

Appendix: source

Thrown at proxy/cmd/caveman-proxy/main.go:945

	if err != nil {
		fatalJSON(logger, err)
	}
	if latest == "" {
		fatalJSON(logger, fmt.Errorf("no trial_id supplied and no trial runs exist"))
	}
	return latest
}

func promoteMove(logger *slog.Logger, home, trialID, optimizerID string, plan store.TrialPlan) {
	var move store.TrialMove
	for _, candidate := range plan.Moves {
		if candidate.OptimizerID == optimizerID {
			move = candidate
			break
		}
	}
	if move.OptimizerID == "" {
		fatalJSON(logger, fmt.Errorf("optimizer %q not found in trial %s", optimizerID, trialID))
	}
	if move.Status != "safe_now" || !(strings.HasPrefix(move.SafetyClass, "S0_") || strings.HasPrefix(move.SafetyClass, "S1_")) {
		path := filepath.Join(home, "reports", "caveman-trial-"+trialID+"-"+optimizerID+"-candidate.yaml")
		if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
			fatalJSON(logger, err)
		}
		raw, _ := yaml.Marshal(map[string]any{
			"mode":         "record",
			"optimizers":   map[string]bool{optimizerID: true},
			"eval_command": "caveman evals run",
		})
		if err := os.WriteFile(path, raw, 0o600); err != nil {
			fatalJSON(logger, err)
		}
		printJSON(map[string]any{
			"trial_id": trialID, "optimizer_id": optimizerID, "promoted": false,
			"candidate_config": path, "eval_command": "caveman evals run",
			"reason": "move is not safe_now S0/S1",

View on GitHub (pinned to 3ee70a1026)