Add dart mcp server events #2112

jakemac53 · 2025-06-17T16:56:03Z

This is more a proposal for potential new analytics events than a PR intended to be merged right now.

Specifically, we should consider whether we want a more general purpose event type, or specific events for different MCP server interactions.

For example we do expose runtime errors as both a tool and a resource currently, depending on the client support. Do we want a separate event to capture access to resources, or should we try and make this more general so we can add that kind of event later on without changes to this package?

github-actions · 2025-06-17T16:56:41Z

Package publishing

Package	Version	Status	Publish tag (post-merge)
package:bazel_worker	1.1.3	already published at pub.dev
package:benchmark_harness	2.4.0-wip	WIP (no publish necessary)
package:boolean_selector	2.1.2	already published at pub.dev
package:browser_launcher	1.1.3	already published at pub.dev
package:cli_config	0.2.1-wip	WIP (no publish necessary)
package:cli_util	0.4.2	already published at pub.dev
package:clock	1.1.3-wip	WIP (no publish necessary)
package:code_builder	4.10.2-wip	WIP (no publish necessary)
package:coverage	1.14.1	already published at pub.dev
package:csslib	1.0.2	already published at pub.dev
package:extension_discovery	2.1.0	already published at pub.dev
package:file	7.0.2-wip	WIP (no publish necessary)
package:file_testing	3.1.0-wip	WIP (no publish necessary)
package:glob	2.1.3	already published at pub.dev
package:graphs	2.3.3-wip	WIP (no publish necessary)
package:html	0.15.6	already published at pub.dev
package:io	1.1.0-wip	WIP (no publish necessary)
package:json_rpc_2	4.0.0	already published at pub.dev
package:markdown	7.3.1-wip	WIP (no publish necessary)
package:mime	2.0.0	already published at pub.dev
package:oauth2	2.0.4-wip	WIP (no publish necessary)
package:package_config	2.3.0-wip	WIP (no publish necessary)
package:pool	1.5.2-wip	WIP (no publish necessary)
package:process	5.0.4	already published at pub.dev
package:pub_semver	2.2.0	already published at pub.dev
package:pubspec_parse	1.5.0	already published at pub.dev
package:source_map_stack_trace	2.1.3-wip	WIP (no publish necessary)
package:source_maps	0.10.14-wip	WIP (no publish necessary)
package:source_span	1.10.1	already published at pub.dev
package:sse	4.1.8	already published at pub.dev
package:stack_trace	1.12.1	already published at pub.dev
package:stream_channel	2.1.4	already published at pub.dev
package:stream_transform	2.1.2-wip	WIP (no publish necessary)
package:string_scanner	1.4.1	already published at pub.dev
package:term_glyph	1.2.3-wip	WIP (no publish necessary)
package:test_reflective_loader	0.3.0	ready to publish	`test_reflective_loader-v0.3.0`
package:timing	1.0.2	already published at pub.dev
package:unified_analytics	8.0.2	ready to publish	`unified_analytics-v8.0.2`
package:watcher	1.1.2	already published at pub.dev
package:yaml	3.1.3	already published at pub.dev
package:yaml_edit	2.2.2	already published at pub.dev

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.

github-actions · 2025-06-17T16:58:58Z

PR Health

Breaking changes

⚠️

Package	Change	Current Version	New Version	Needed Version	Looking good?
unified_analytics	Breaking	8.0.1	8.0.2	9.0.0 Got "8.0.2" expected >= "9.0.0" (breaking changes)	⚠️

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Coverage

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File	Coverage
pkgs/unified_analytics/lib/src/constants.dart	💔 Not covered
pkgs/unified_analytics/lib/src/enums.dart	💚 100 %
pkgs/unified_analytics/lib/src/event.dart	💚 98 % ⬆️ 0 %

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// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

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Files
pkgs/bazel_worker/benchmark/benchmark.dart
pkgs/bazel_worker/example/client.dart
pkgs/bazel_worker/example/worker.dart
pkgs/benchmark_harness/integration_test/perf_benchmark_test.dart
pkgs/boolean_selector/example/example.dart
pkgs/clock/lib/clock.dart
pkgs/clock/lib/src/clock.dart
pkgs/clock/lib/src/default.dart
pkgs/clock/lib/src/stopwatch.dart
pkgs/clock/lib/src/utils.dart
pkgs/clock/test/clock_test.dart
pkgs/clock/test/default_test.dart
pkgs/clock/test/stopwatch_test.dart
pkgs/clock/test/utils.dart
pkgs/coverage/lib/src/coverage_options.dart
pkgs/html/example/main.dart
pkgs/html/lib/dom.dart
pkgs/html/lib/dom_parsing.dart
pkgs/html/lib/html_escape.dart
pkgs/html/lib/parser.dart
pkgs/html/lib/src/constants.dart
pkgs/html/lib/src/encoding_parser.dart
pkgs/html/lib/src/html_input_stream.dart
pkgs/html/lib/src/list_proxy.dart
pkgs/html/lib/src/query_selector.dart
pkgs/html/lib/src/token.dart
pkgs/html/lib/src/tokenizer.dart
pkgs/html/lib/src/treebuilder.dart
pkgs/html/lib/src/utils.dart
pkgs/html/test/dom_test.dart
pkgs/html/test/parser_feature_test.dart
pkgs/html/test/parser_test.dart
pkgs/html/test/query_selector_test.dart
pkgs/html/test/selectors/level1_baseline_test.dart
pkgs/html/test/selectors/level1_lib.dart
pkgs/html/test/selectors/selectors.dart
pkgs/html/test/support.dart
pkgs/html/test/tokenizer_test.dart
pkgs/html/test/trie_test.dart
pkgs/html/tool/generate_trie.dart
pkgs/pubspec_parse/test/git_uri_test.dart
pkgs/stack_trace/example/example.dart
pkgs/watcher/test/custom_watcher_factory_test.dart
pkgs/yaml_edit/example/example.dart

pkgs/unified_analytics/lib/src/event.dart

kenzieschmoll · 2025-06-17T17:09:28Z

Cross linking tracking issue: #2112

kenzieschmoll · 2025-06-17T17:11:30Z

Specifically, we should consider whether we want a more general purpose event type, or specific events for different MCP server interactions.

For example we do expose runtime errors as both a tool and a resource currently, depending on the client support. Do we want a separate event to capture access to resources, or should we try and make this more general so we can add that kind of event later on without changes to this package?

We could add a parameter type instead where type is 'tool', 'resource', 'prompt', etc. That would make it easier to tweak analytics events down the road without needing to make a change to this package. We took a more general approach for DevTools analytics sent through the unified_analytics package and it made development much simpler to not have to change & publish this package just to add a new event.

jakemac53 · 2025-06-17T19:13:17Z

We could add a parameter type instead where type is 'tool', 'resource', 'prompt', etc. That would make it easier to tweak analytics events down the road without needing to make a change to this package. We took a more general approach for DevTools analytics sent through the unified_analytics package and it made development much simpler to not have to change & publish this package just to add a new event.

Yeah, I just don't know if we need more specific types or not, if generic events are fine I would lean towards that direction.

kenzieschmoll · 2025-06-17T19:33:03Z

Generic events are fine to use. We can just pass some event label in the data and then use that to look it up in queries. Take a look at devtoolsEvent for an example. We send every DevTools analytics event through this single unified analytics event.

jakemac53 · 2025-06-17T20:38:43Z

Ok, I made the events more generic and also added a field for the MCP server version.

jakemac53 · 2025-06-17T21:15:33Z

(note that I will update tests once we agree on a structure for these events)

jakemac53 · 2025-06-17T21:35:48Z

~~Fwiw, when I tested using these events in the actual MCP server, I am getting errors because of the CustomMetrics field.~~

~~It doesn't appear that Maps are actually allowed, so this whole CustomMetrics class seems like it needs to be deprecated.~~

~~We could encode all the event data as a String... although that seems less than ideal. May want to move as many shared components out as possible (like elapsed milliseconds).~~

Nevermind, I see the DevTools strategy is just to flatten all the fields directly into the parent map, that works.

kenzieschmoll

LGTM once this is approved from a product perspective @anderdobo

pkgs/unified_analytics/lib/src/event.dart

jakemac53 · 2025-06-23T15:19:30Z

pkgs/unified_analytics/lib/src/enums.dart

@@ -55,6 +55,11 @@ enum DashEvent {
    description: 'Pub package resolution details',
    toolOwner: DashTool.dartTool,
  ),
+  dartMCPEvent(


Note: I assume I don't have to consider this breaking since it isn't exported publicly.

jakemac53 · 2025-06-23T15:27:12Z

Ok, I just pushed up the test and pubspec/changelog updates, PTAL.

Are we ok to publish this right after the merge?

kenzieschmoll · 2025-06-23T18:27:46Z

pkgs/unified_analytics/lib/src/event.dart

+  ///
+  /// The [serverVersion] is the version of the Dart MCP server.
+  ///
+  /// The [type] identifies the kind of event this is, and [eventData] is the


do we have a list of the expected event types? should we use an enum?

It will live in the dart_mcp_server package

Is there a reason it should live there an not here? If it lives here, we can enforce the parameter to have the enum type and guarantee what types of events are getting sent to analytics. Otherwise, any string could be passed in here and the enum values are not enforced.

It doesn't have to be this way, I was mostly just replicating how the devtools events work, but I think there are two primary reasons:

It makes it easier to add new events

These are public which means adding a new event would be a breaking change in this package which would be unfortunate (adding values to public enums breaks switches and other exhaustiveness checks)

Fair points. Fine to leave in dart_mcp_server then.

pkgs/unified_analytics/lib/src/event.dart

Based on dart-lang/tools#2112 Adds analytics events for all tool calls as well as for the runtime errors resource. We could consider a generic resource read event which includes the URI, but we could accidentally create URIs that have some information we don't want to capture, so I chose to instead just customize this and not provide the URI, but a field that describes the type of resource that was read. I did not add any debouncing because I don't think it is necessary, LLMs do not invoke tools in super rapid succession generally, but let me know if you all disagree and think I should do some debouncing.

add events for dart mcp server tool invocations

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jakemac53 requested a review from kenzieschmoll June 17, 2025 16:56

jakemac53 requested review from bkonyi and a team as code owners June 17, 2025 16:56

github-actions bot added the package:unified_analytics label Jun 17, 2025

kenzieschmoll reviewed Jun 17, 2025

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kenzieschmoll mentioned this pull request Jun 12, 2025

Add telemetry for tool usage from the dart mcp-server command dart-lang/sdk#60901

Open

add client and clientVersion fields

04bcae1

make the event generic

941da2b

rename the event enum as well

46c958c

inline the additional data directly into the parent map

ea33429

jakemac53 mentioned this pull request Jun 17, 2025

add analytics support to the Dart MCP server dart-lang/ai#174

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kenzieschmoll reviewed Jun 18, 2025

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bkonyi approved these changes Jun 23, 2025

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jakemac53 changed the title ~~[WIP] add events for dart mcp server tool invocations~~ Add events for dart mcp server tool invocations Jun 23, 2025

Merge branch 'main' into mcp-server-events

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jakemac53 commented Jun 23, 2025

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add pubspec version, changelog, and test

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jakemac53 requested a review from kenzieschmoll June 23, 2025 15:28

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update comment

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jakemac53 requested a review from kenzieschmoll June 23, 2025 22:16

kenzieschmoll approved these changes Jun 24, 2025

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jakemac53 changed the title ~~Add events for dart mcp server tool invocations~~ Add dart mcp server events Jun 24, 2025

jakemac53 merged commit 9b35b98 into dart-lang:main Jun 24, 2025
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jakemac53 deleted the mcp-server-events branch June 24, 2025 16:42

Add dart mcp server events #2112

Add dart mcp server events #2112

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