different-ai/openwork · error

MCP_PROVIDER_TOOL_ERROR

MCP_PROVIDER_TOOL_ERROR

Error message

Inspect the provider operation result and provider logs using the diagnostic reference.

What it means

This is the fallback tool-execution classification: the provider responded with an error that is not invalid-arguments, not 403, and not 429, so the classifier emits provider_tool_error at phase PROVIDER_EXECUTION, non-retryable, owned by the provider admin. It typically represents a provider-side tool error result (e.g. the MCP tool returned isError or the upstream operation failed inside the provider).

Solutions

1. Inspect the provider operation result payload for the error detail and correlate with provider-side logs using the diagnostic reference.
2. Check the provider's status page/health endpoints for an ongoing incident.
3. Reproduce with a minimal tool call to determine if it's input-specific or a provider fault.
4. Report to the provider admin with the diagnostic reference; retry only after the provider confirms the fault is fixed.

Example fix

// before: blind retry on any tool failure
try { return await callTool(name, args); } catch { return callTool(name, args); }
// after: log diagnostic and surface instead of blind retry
catch (e) { logDiagnostic('MCP_PROVIDER_TOOL_ERROR', e); throw e; }

const health = await fetch(`${providerBase}/healthz`).then(r => r.status);
if (health !== 200) throw new Error(`Provider unhealthy (status ${health}); skipping tool call`);

function isProviderToolError(d: { code: string }): boolean {
  return d.code === 'MCP_PROVIDER_TOOL_ERROR';
}

try { return await callTool(name, args); } catch (e) {
  if (isProviderToolError(e.diagnostic)) { logWithDiagnosticReference(e); notifyProviderAdmin(e.diagnostic); throw e; }
  throw e;
}

When it happens

Trigger: MCP tool call where the provider itself reports the operation failed: the tool returned an error result, the provider's upstream dependency failed, unhandled provider exception (5xx), or malformed provider response that fits no other classification bucket.

Common situations: Provider's backend service down or degraded; provider bug triggered by valid input; provider database/dependency outage; provider returning 500 on a specific resource; tool timing out internally and surfacing an error result.

Related errors

• MCP_APP_RESOURCE_RESOLUTION_FAILED
• MCP_PROVIDER_DECLARED_ERROR
• MCP_PROVIDER_INVALID_PARAMS
• MCP_PROVIDER_INVALID_PARAMS|MCP_PROVIDER_HTTP_403|MCP_PROVIDER_HTTP_429
• is no longer available as your reconnectable account.

AI-assisted analysis of different-ai/openwork@2b7df46e8a (2026-09-01). Data as JSON: /api/errors/e0566e4d53ecd59c. Report an issue: GitHub.

Appendix: source

Thrown at ee/apps/den-api/src/capability-sources/external-mcp-diagnostics.ts:1596

          category: "provider_policy_denied",
          code: "MCP_PROVIDER_HTTP_403",
          retryable: false,
          actionOwner: "provider_admin",
          operatorAction: "Grant the provider role, ACL, or application permission required for this operation.",
        }
      : providerStatus === 429
        ? {
            phase: "PROVIDER_EXECUTION",
            category: "provider_throttled",
            code: "MCP_PROVIDER_HTTP_429",
            retryable: true,
            actionOwner: "provider_admin",
            operatorAction: "Wait for the provider rate limit to reset, then retry with bounded backoff.",
          }
        : {
            phase: "PROVIDER_EXECUTION",
            category: "provider_tool_error",
            code: "MCP_PROVIDER_TOOL_ERROR",
            retryable: false,
            actionOwner: "provider_admin",
            operatorAction: "Inspect the provider operation result and provider logs using the diagnostic reference.",
          }
    const classification: Classification = {
      ...classificationBase,
      ...(providerStatus === undefined ? {} : { providerStatus }),
      ...(providerCode ? { providerCode } : {}),
      payloadBytes: evidence.payloadBytes,
      ...(evidence.excerpt ? { providerErrorMessage: evidence.excerpt } : {}),
    }
    logProviderToolEvidence({
      referenceId: this.referenceId,
      evidence,
      diagnosticCode: classification.code,
      ...(providerStatus === undefined ? {} : { providerStatus }),
      ...(providerCode ? { providerCode } : {}),
      ...(requestId ? { providerRequestId: requestId } : {}),

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