microsoft/semantic-kernel · error · AggregateException

Plugin creation failed for

Error message

Plugin creation failed for {pluginName}

What it means

The catch block wraps any failure of ImportPluginFromCopilotAgentPluginAsync in an AggregateException with the plugin name. Note: AggregateException wrapping a single inner exception is slightly misleading (AggregateException implies multiple errors); the original cause is in InnerException. The log line is written first, then the throw propagates.

Solutions

  1. Read ex.InnerException (and the preceding log line) for the real cause before the AggregateException.
  2. Confirm GetCopilotAgentManifestPath(pluginName) returns a reachable, valid manifest path.
  3. Validate the manifest JSON against the Copilot Agent plugin schema.
  4. Supply any required copilotAgentPluginParameters the manifest expects.

Example fix

// before
catch (Exception ex)
{
    AnsiConsole.MarkupLine($"[red]Failed to load {pluginName}.[/]");
    kernel.LoggerFactory.CreateLogger("Plugin Creation").LogError(ex, "Plugin creation failed. Message: {0}", ex.Message);
    throw new AggregateException($"Plugin creation failed for {pluginName}", ex);
}

// after (preserve true cause; only wrap when you actually aggregate)
catch (Exception ex)
{
    logger.LogError(ex, "Plugin creation failed for {Plugin}", pluginName);
    throw new InvalidOperationException($"Plugin creation failed for {pluginName}. See inner exception.", ex);
}
Defensive patterns

Strategy: try-catch

Validate before calling

var manifestPath = GetCopilotAgentManifestPath(pluginName);
if (!File.Exists(manifestPath) && !Uri.IsWellFormedUriString(manifestPath, UriKind.Absolute))
    throw new FileNotFoundException($"Plugin manifest not found: {manifestPath}", manifestPath);

Type guard

static bool ManifestReachable(string path) =>
    File.Exists(path) || Uri.IsWellFormedUriString(path, UriKind.Absolute);

Try / catch

try { await kernel.ImportPluginFromCopilotAgentPluginAsync(...); }
catch (Exception ex)
{
    logger.LogError(ex, "Plugin creation failed for {Plugin}", pluginName);
    throw new InvalidOperationException($"Plugin creation failed for {pluginName}.", ex);
}

Prevention

When it happens

Trigger: ImportPluginFromCopilotAgentPluginAsync throws — invalid manifest path, malformed Copilot Agent plugin manifest, missing parameters (copilotAgentPluginParameters), network failure fetching the manifest, or schema validation failure inside the importer.

Common situations: Plugin name doesn't map to a manifest path, the manifest JSON doesn't match the expected Copilot Agent schema, required runtime arguments were not supplied, or the manifest URL is unreachable.

Related errors

AI-assisted analysis of microsoft/semantic-kernel@c028a0c7dc (2026-08-13). Data as JSON: /api/errors/5621edff1544e7e0. Report an issue: GitHub.

Appendix: source

Thrown at dotnet/samples/Demos/CopilotAgentPlugins/CopilotAgentPluginsDemoSample/DemoCommand.cs:384

                { "https://api.nasa.gov/planetary", new OpenApiFunctionExecutionParameters(authCallback: GetApiKeyAuthProvider("DEMO_KEY", "api_key", false), enableDynamicOperationPayload: false, enablePayloadNamespacing: true)}
            },
        };

        try
        {
            KernelPlugin plugin =
            await kernel.ImportPluginFromCopilotAgentPluginAsync(
                pluginName,
                GetCopilotAgentManifestPath(pluginName),
                copilotAgentPluginParameters)
                .ConfigureAwait(false);
            AnsiConsole.MarkupLine($"[bold green] {pluginName} loaded successfully.[/]");
        }
        catch (Exception ex)
        {
            AnsiConsole.MarkupLine($"[red]Failed to load {pluginName}.[/]");
            kernel.LoggerFactory.CreateLogger("Plugin Creation").LogError(ex, "Plugin creation failed. Message: {0}", ex.Message);
            throw new AggregateException($"Plugin creation failed for {pluginName}", ex);
        }
    }
    #region MagicDoNotLookUnderTheHood
    private static readonly HashSet<string> s_fieldsToIgnore = new(
        [
            "@odata.type",
            "attachments",
            "allowNewTimeProposals",
            "bccRecipients",
            "bodyPreview",
            "calendar",
            "categories",
            "ccRecipients",
            "changeKey",
            "conversationId",
            "coordinates",
            "conversationIndex",
            "createdDateTime",

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