googleapis/mcp-toolbox · error

failed to initialize resources: %w

Error message

failed to initialize resources: %w

What it means

The `invoke` CLI command calls server.InitializeConfigs to build all sources, auth services, embedding models, tools, prompts, and groups from the resolved config. If any of those components fails to initialize (bad YAML, unresolvable source connection, invalid tool definition, duplicate names), the whole run aborts with this wrapped error. The original underlying error is preserved via %w, so it names the actual failing resource.

Source

Thrown at cmd/internal/invoke/command.go:70

	defer cancel()

	ctx, shutdown, err := opts.Setup(ctx)
	if err != nil {
		return err
	}
	defer func() {
		_ = shutdown(ctx)
	}()

	_, err = opts.LoadConfig(ctx, &internal.ConfigParser{})
	if err != nil {
		return err
	}

	// Initialize Resources
	sourcesMap, authServicesMap, embeddingModelsMap, toolsMap, promptsMap, groupsMap, err := server.InitializeConfigs(ctx, opts.Cfg)
	if err != nil {
		errMsg := fmt.Errorf("failed to initialize resources: %w", err)
		opts.Logger.ErrorContext(ctx, errMsg.Error())
		return errMsg
	}

	primitiveMgr := primitives.NewPrimitiveManager(sourcesMap, authServicesMap, embeddingModelsMap, toolsMap, promptsMap, groupsMap)

	// Execute Tool
	toolName := args[0]
	tool, ok := primitiveMgr.GetTool(toolName)
	if !ok {
		errMsg := fmt.Errorf("tool %q not found", toolName)
		opts.Logger.ErrorContext(ctx, errMsg.Error())
		return errMsg
	}

	srcName := tool.GetSourceName()
	var src sources.Source
	if srcName != "" {

View on GitHub (pinned to 8cc6e09de2)

Solutions

1. Read the wrapped cause after this message — it names the exact resource (source/tool/prompt) that failed to initialize
2. Run `toolbox validate` (or start the server once) to surface the same config error before invoking
3. Check source connectivity: verify connection strings, credentials, and that the database is reachable from this host
4. If a version upgrade broke it, diff your tools file against the release's config schema/docs

Example fix

// before
toolbox invoke --tools-file tools.yaml my-tool
// failed to initialize resources: source "db" failed to connect: password authentication failed
// after
# fix credentials/connection in tools.yaml, validate first:
toolbox validate --tools-file tools.yaml
toolbox invoke --tools-file tools.yaml my-tool

// validate config before invoking
cmd := exec.Command("toolbox", "validate", "--tools-file", cfgPath)
if out, err := cmd.CombinedOutput(); err != nil {
    return fmt.Errorf("invalid config: %s", out)
}

if err := runInvoke(ctx, opts); err != nil {
    var initErr *fmt.WrapError // or check via errors.As/Unwrap
    if strings.Contains(err.Error(), "failed to initialize resources") {
        cause := errors.Unwrap(err)
        log.Printf("resource init failed: %v", cause)
        // route to config-fix path, not retry
    }
    return err
}

When it happens

Trigger: Running `toolbox invoke <tool> ...` (runInvoke) where InitializeConfigs fails: malformed config YAML, a source that cannot connect during initialization, an unknown auth service referenced by a tool, or invalid prompt/group definitions.

Common situations: Typo in tools-file kind/name fields, database credentials wrong or network unreachable so source init fails, referencing a source that isn't defined, incompatible config version after upgrading the toolbox binary.

Related errors

• tool %q not found
• unable to retrieve source for tool %s
• failed to initialize resources: %w
• unable to initialize reloaded configs: %w
• error generating script content for %s: %w

AI-assisted analysis of googleapis/mcp-toolbox@8cc6e09de2 (2026-09-05). Data as JSON: /api/errors/ce3c506b6983f0ea. Report an issue: GitHub.