googleapis/mcp-toolbox · error

can't convert types to array of strings: %w

Error message

can't convert types to array of strings: %w

What it means

InvokeSearchCatalog converts the types parameter (Dataplex entry type filters such as TABLE, DATASET) from []any to []string using parameters.ConvertAnySliceToTyped. If elements are not strings the conversion fails with this wrapped error, preventing invalid type filters from reaching ConstructSearchQuery.

Source

Thrown at internal/sources/dataplex/searchcatalog/search_catalog.go:158

) ([]DataplexSearchResponse, error) {
	pageSize := int32(paramsMap["pageSize"].(int))
	prompt, _ := paramsMap["prompt"].(string)

	projectIdSlice, err := parameters.ConvertAnySliceToTyped(paramsMap["projectIds"].([]any), "string")
	if err != nil {
		return nil, fmt.Errorf("can't convert projectIds to array of strings: %w", err)
	}
	projectIds := projectIdSlice.([]string)

	parentIdSlice, err := parameters.ConvertAnySliceToTyped(paramsMap[parentParamName].([]any), "string")
	if err != nil {
		return nil, fmt.Errorf("can't convert %s to array of strings: %w", parentParamName, err)
	}
	parentIds := parentIdSlice.([]string)

	typesSlice, err := parameters.ConvertAnySliceToTyped(paramsMap["types"].([]any), "string")
	if err != nil {
		return nil, fmt.Errorf("can't convert types to array of strings: %w", err)
	}
	types := typesSlice.([]string)

	query := ConstructSearchQuery(prompt, projectIds, parentIds, types, systemName)

	req := &dataplexpb.SearchEntriesRequest{
		Query:          query,
		Name:           fmt.Sprintf("projects/%s/locations/global", projectID),
		PageSize:       pageSize,
		SemanticSearch: true,
	}

	catalogClient, err := getCatalogClient(ctx, tokenStr)
	if err != nil {
		return nil, fmt.Errorf("failed to get catalog client: %w", err)
	}

	return ExecuteSearch(ctx, catalogClient, req, typeMap)

View on GitHub (pinned to 8cc6e09de2)

Solutions

1. Send types as an array of strings, e.g. ["TABLE","VIEW"], or [] if empty
2. Ensure the key exists (empty array rather than omitted) if the client always serializes it
3. Normalize any enum-like values to plain uppercase strings
4. Validate client-side that every element is a string before invoking

Example fix

// before
{"types": [null, {"type": "TABLE"}]}
// after
{"types": ["TABLE"]}

func allStrings(v []any) bool {
	for _, e := range v { if _, ok := e.(string); !ok { return false } }
	return true
}
// require types (if present) to be []any of strings

t, ok := paramsMap["types"].([]any); if ok && !allStrings(t) { return errors.New("types must be strings") }

res, err := searchcatalog.InvokeSearchCatalog(ctx, src, params)
if err != nil {
	if strings.Contains(err.Error(), "can't convert types") {
		return fmt.Errorf("types must be an array of strings: %w", err)
	}
	return err
}

When it happens

Trigger: Invoking search_catalog with types containing non-string values (numbers, booleans, null entries) or the key absent so the type assertion to []any fails.

Common situations: Clients omitting types (key missing) instead of sending an empty array; agents passing type objects/dicts instead of plain strings; casing mistakes are fine value-wise but only string type matters here.

Related errors

• can't convert projectIds to array of strings: %w
• can't convert %s to array of strings: %w
• dataplex catalog client is nil
• failed to create search entries iterator
• can't convert fields to array of strings: %s

AI-assisted analysis of googleapis/mcp-toolbox@8cc6e09de2 (2026-09-05). Data as JSON: /api/errors/a166efac795a86ee. Report an issue: GitHub.