What causes "error applying model settings: %v" in plandex-ai/plandex?

Inspect the inner error: if it mentions the settings file path, re-create the file (e.g. via checkout) before syncing.

error applying model settings: %v

Error message

error applying model settings: %v

What it means

SyncPlanModelSettings calls ApplyModelSettings on the local plan settings file to merge local model-pack changes into the fetched server settings. If ApplyModelSettings returns an error (file read, validation, copy, or hash-save failure inside it), it is wrapped here. Caution: this line wraps `err` (the GetSettings error variable) instead of `apiErr`, so the message can misreport the underlying cause — a common source of confusing diagnostics.

Source

Thrown at app/cli/lib/model_settings.go:207

	err = WriteModelSettingsFile(path, settings)
	if err != nil {
		return false, fmt.Errorf("error writing model settings file: %v", err)
	}

	return true, nil
}

// save settings in file to server
func SyncPlanModelSettings() error {
	settings, err := api.Client.GetSettings(CurrentPlanId, CurrentBranch)
	if err != nil {
		return fmt.Errorf("error getting settings: %v", err)
	}

	updatedSettings, apiErr := ApplyModelSettings(GetPlanModelSettingsPath(CurrentPlanId), settings)
	if apiErr != nil {
		return fmt.Errorf("error applying model settings: %v", err)
	}

	res, updateErr := api.Client.UpdateSettings(CurrentPlanId, CurrentBranch, shared.UpdateSettingsRequest{
		ModelPackName: updatedSettings.ModelPackName,
		ModelPack:     updatedSettings.ModelPack,
	})

	if updateErr != nil {
		return fmt.Errorf("error updating settings: %v", err)
	}

	if res == nil {
		return nil
	}

	fmt.Println(res.Msg)

	return nil

View on GitHub (pinned to e2d772072e)

Solutions

Inspect the inner error: if it mentions the settings file path, re-create the file (e.g. via checkout) before syncing.
Fix JSON validation errors reported above the error (ValidateModelPackInlineJSON prints details) in the settings file.
Fix the wrapping bug: change `fmt.Errorf("error applying model settings: %v", err)` to wrap `apiErr` so future errors point at the real cause.
Check write permissions on the directory where SaveModelPackRolesHash stores the hash file.

Example fix

// before (bug: wraps wrong variable)
updatedSettings, apiErr := ApplyModelSettings(GetPlanModelSettingsPath(CurrentPlanId), settings)
if apiErr != nil {
    return fmt.Errorf("error applying model settings: %v", err)
}
// after
updatedSettings, apiErr := ApplyModelSettings(GetPlanModelSettingsPath(CurrentPlanId), settings)
if apiErr != nil {
    return fmt.Errorf("error applying model settings: %w", apiErr)
}

Defensive patterns

Strategy: validation

Validate before calling

path := lib.GetPlanModelSettingsPath(planID)
if _, err := os.Stat(path); os.IsNotExist(err) {
    return fmt.Errorf("no local settings at %s; run checkout first before SyncPlanModelSettings", path)
}
data, _ := os.ReadFile(path)
if jerr := json.Unmarshal(data, &json.RawMessage{}); jerr != nil {
    return fmt.Errorf("local settings invalid JSON, ApplyModelSettings will fail: %w", jerr)
}

Type guard

func localSettingsReady(path string) bool {
    data, err := os.ReadFile(path)
    if err != nil { return false }
    var v any
    return json.Unmarshal(data, &v) == nil
}

Try / catch

err := lib.SyncPlanModelSettings()
if err != nil && strings.Contains(err.Error(), "error applying model settings") {
    // NOTE: library wraps the wrong variable here; inspect the inner text,
    // fix the settings file, and retry
    log.Warnf("apply failed: %v", err)
    return regenerateLocalSettingsThenRetry()
}

Prevention

Always run checkout/initialize before sync so the settings file exists.
Validate the settings JSON after any manual edit.
Ensure the hash sidecar directory is writable.
Patch the library to wrap apiErr instead of err for accurate messages.

When it happens

Trigger: ApplyModelSettings fails: the settings file is missing or unreadable, ValidateModelPackInlineJSON rejects the JSON (which also os.Exit(1)s), DeepCopy fails, or SaveModelPackRolesHash fails writing the hash file.

Common situations: The plan settings file was deleted before sync; the JSON was hand-edited into an invalid model pack; the hash sidecar file's directory is read-only; running sync before any local settings were ever written.

Related errors

AI-assisted analysis of plandex-ai/plandex@e2d772072e (2026-09-05). Data as JSON: /api/errors/d99dfc7a415308b6. Report an issue: GitHub.