What causes "source is not compatible with the tool" in googleapis/mcp-toolbox?

Set the tool's source field to a compatible bigtable source

source is not compatible with the tool

Error message

source is not compatible with the tool

What it means

Thrown by the bigtableupdatetable Tool.ValidateSource when the supplied sources.Source does not implement the tool's compatibleSource interface. The table-update operation is rejected before any API call.

Source

Thrown at internal/tools/bigtable/bigtableupdatetable/bigtableupdatetable.go:95

			allParameters,
		),
	}, nil
}

var _ tools.Tool = Tool{}

type Tool struct {
	tools.BaseTool[Config]
}

func (t Tool) GetSourceName() string {
	return t.Cfg.Source
}

func (t Tool) ValidateSource(src sources.Source) error {
	_, ok := src.(compatibleSource)
	if !ok {
		return fmt.Errorf("source is not compatible with the tool")
	}
	return nil
}

func (t Tool) ToConfig() tools.ToolConfig {
	return t.Cfg
}

func (t Tool) Invoke(ctx context.Context, src sources.Source, params parameters.ParamValues, accessToken tools.AccessToken) (any, util.ToolboxError) {
	source, ok := src.(compatibleSource)
	if !ok {
		return nil, util.NewClientServerError("source used is not compatible with the tool", http.StatusInternalServerError, nil)
	}

	paramsMap := params.AsMap()

	res, err := source.UpdateTable(ctx, paramsMap["table_id"].(string), paramsMap["disable_change_stream"].(bool))
	if err != nil {

View on GitHub (pinned to 8cc6e09de2)

Solutions

Set the tool's source field to a compatible bigtable source
Confirm the source is initialized as a Bigtable source
Restart the toolbox so the corrected pairing takes effect
Pass the right concrete Source type when calling Invoke directly

Example fix

// before (tools.yaml)
tools:
  update-table:
    kind: bigtable-update-table
    source: my-sql-server
// after
tools:
  update-table:
    kind: bigtable-update-table
    source: my-bigtable-instance

Defensive patterns

Strategy: type-guard

Validate before calling

// Confirm compatibility before invoking the table-update tool
if err := tool.ValidateSource(mySource); err != nil {
    return fmt.Errorf("source %s is not compatible with bigtable-update-table", sourceName)
}

Type guard

func isCompatibleUpdateTableSource(s sources.Source) bool {
    _, ok := s.(bigtableupdatetable.CompatibleSource)
    return ok
}

Prevention

Reference bigtable sources for bigtable-update-table
Validate the config at startup so mismatches fail fast
Track source renames with grep across tools.yaml
Keep per-kind source naming conventions to reduce wiring mistakes

When it happens

Trigger: ValidateSource/Invoke receives a source failing the type assertion to bigtableupdatetable's compatibleSource — the tool is wired to an incompatible source in tools.yaml or in code.

Common situations: Config mistake where the update-table tool references a non-Bigtable source; copy-pasted tool blocks; renamed sources not propagated to tools.

Related errors

AI-assisted analysis of googleapis/mcp-toolbox@8cc6e09de2 (2026-09-05). Data as JSON: /api/errors/6e1d1b40e550a278. Report an issue: GitHub.