Implement getBuildArtifacts tool and optimize getBuild response by dt-atmosic · Pull Request #42 · jenkinsci/mcp-server-plugin

dt-atmosic · 2025-09-01T05:19:22Z

This PR implements issue #32 by adding new tools for artifact management and optimizing the getBuild response size.

New Tools Added

getBuildArtifacts - Returns only the artifacts array from a build
o Takes jobFullName and optional buildNumber parameters
o Significantly reduces payload size compared to full getBuild response
o Returns empty array for jobs without artifacts or non-existent jobs
o Fixed JSON concatenation issue for top-level lists
getBuildArtifact - Provides paginated access to individual artifact file contents
o Supports offset/limit parameters for large files
o Returns artifact content as text with pagination metadata
o Includes safety limits to prevent excessive memory usage

Optimizations

Modified getBuild response - Now excludes artifacts field
o Created RunWithoutArtifactsSerializer to filter out artifacts
o Updated JenkinsExportedBeanSerializerModifier to use custom serializer
o Maintains all other build information while reducing response size

Testing done

Comprehensive test coverage
o BuildArtifactsExtensionTest - Integration tests for new tools
o GetBuildWithoutArtifactsTest - Verifies getBuild optimization
o BuildArtifactsExtensionCompileTest - Basic compilation verification
Manual test
o Augment Code MCP client w/ mvn hpi:run - Found JSON issue with top-level list
o Manual test with Augment Code and production Jenkins server

Submitter checklist

Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
Ensure that the pull request title represents the desired changelog entry
Please describe what you did
Link to relevant issues in GitHub or Jira
Link to relevant pull requests, esp. upstream and downstream changes
Ensure you have provided tests that demonstrate the feature works or the issue is fixed

- Add BuildArtifactsExtension with getBuildArtifacts and getBuildArtifact tools - Create RunWithoutArtifactsSerializer to exclude artifacts from getBuild responses - Add comprehensive tests for new functionality - Implement pagination support for large artifact files - Maintain backward compatibility while reducing payload sizes Addresses first part of issue jenkinsci#32: separate artifacts retrieval from build metadata

- Replace Java record with regular class for Java 11 compatibility - Fix regex pattern in RunWithoutArtifactsSerializer with DOTALL flag - Update test methods to use proper McpSchema.TextContent pattern - Remove non-existent TestUtils.getTextContent() method calls - Follow existing test patterns from the codebase

- Declare ObjectMapper inside lambda scope where it's used - Resolves compilation error in GetBuildWithoutArtifactsTest.java

- Use record for BuildArtifactResponse - Use TreePruner - spotless:apply

dt-atmosic · 2025-10-20T23:56:24Z

Working on the code coverage warnings.

olamy

Nice PR.
the title says optimize getBuild response. is it remove artifacts from the tree?

olamy · 2025-10-23T01:34:40Z

+     * - "unchecked": Run.getArtifacts() returns raw List requiring unchecked conversion
+     */
+    @SuppressWarnings({"rawtypes", "unchecked"})
+    @Tool(description = "Get the artifacts for a specific build or the last build of a Jenkins job")


will need annotations = @Tool.Annotations(destructiveHint = false)
as it's true per default

Done — added annotations = @Tool.Annotations(destructiveHint = false) to getBuildArtifacts.

olamy · 2025-10-23T01:35:00Z

+                .orElse(List.of());
+    }
+
+    @Tool(


will need annotations = @Tool.Annotations(destructiveHint = false)
as it's true per default

Done — added annotations = @Tool.Annotations(destructiveHint = false) to getBuildArtifact as well.

olamy · 2025-10-23T01:36:41Z

+            offset = 0L;
+        }
+        if (limit == null || limit <= 0) {
+            limit = 65536; // 64KB default


might be better having a configuration (e.g SystemProperties) as users may want to configure more or less.

Done. The default is now read from a system property: SystemProperties.getInteger("io.jenkins.plugins.mcp.server.extensions.BuildArtifactsExtension.limit.default", 65536), so it still defaults to 64KB but can be tuned.

olamy · 2025-10-23T01:37:04Z

+        }
+
+        // Cap the limit to prevent excessive memory usage
+        final int maxLimit = 1048576; // 1MB max


same here. should be configurable

Done. The cap is now SystemProperties.getInteger("io.jenkins.plugins.mcp.server.extensions.BuildArtifactsExtension.limit.max", 1048576) — defaults to 1MB, configurable.

olamy · 2025-10-23T01:40:48Z

-            }
+            // Serialize all results the same way - this fixes the JSON concatenation issue
+            // for top-level lists while maintaining proper JSON structure
+            resultBuilder.addTextContent(toJson(result));


great. it's going to the direction of #82

Agreed. I've merged the latest main, which includes the ToolResponse refactor from #82. I dropped this local toMcpResult change in favor of upstream's implementation, so list/single results are now handled consistently there.

olamy · 2025-10-23T01:41:28Z

-            } else {
-                resultBuilder.addTextContent(toJson(result));
-            }
+            // Serialize all results the same way - this fixes the JSON concatenation issue


no need of this comment here.
it;s more a PR comment :)

Removed — this whole toMcpResult change was reverted in favor of upstream's ToolResponse (#82), so the comment no longer exists.

olamy · 2025-10-23T01:44:19Z

+            }
+
+            // Convert to string (assuming text content)
+            String content = new String(buffer, 0, bytesRead, StandardCharsets.UTF_8);


what about binaries artifacts? (we can attach jar, war etc....)

Good point. getBuildArtifact now detects binary content (NUL-byte sniff over the read buffer) and returns a clear message — "Artifact appears to be binary and cannot be returned as text: " — instead of emitting garbled UTF-8. getBuildArtifacts still lists every artifact (binary or not) for discovery. Added test coverage in testGetBuildArtifactBinary. Let me know if you'd prefer base64 streaming instead.

…EZXC06JZW1B # Conflicts: # README.md # src/main/java/io/jenkins/plugins/mcp/server/tool/McpToolWrapper.java # src/test/java/io/jenkins/plugins/mcp/server/EndPointTest.java # src/test/java/io/jenkins/plugins/mcp/server/extensions/DefaultMcpServerTest.java

… tree-prune compat - Add @Tool.Annotations(destructiveHint=false) to getBuildArtifacts/getBuildArtifact - Make default/max artifact size limits configurable via SystemProperties - Detect binary artifacts and refuse with a clear message instead of garbled text - Rework RunWithoutArtifactsSerializer to honor the upstream 'tree' parameter while still always excluding artifacts - Update tests for the ToolResponse {status,message,result} wrapper and add binary-artifact coverage

dt-atmosic · 2026-05-30T06:19:09Z

Nice PR. the title says optimize getBuild response. is it remove artifacts from the tree?

Thanks! Yes, that's correct.

novinxy · 2026-07-29T10:54:18Z

Hi, nice PR, just something we need from the MCP 👍
@dt-atmosic isn't it already finished? In my opinion and from the conversation it looks as everything/almost everything is resolved
Is there something I could do to help make it happen ?

dustymabe · 2026-07-30T19:10:27Z

Hi. Thanks for working on this!

I notice we now have some filtering for binary artifacts. One use case to consider is people running a $test_framework inside of Jenkins to perform tests and the tool generates logs itself (additional logs to the ones output to stdout/stderr). As part of the job run the logs from the tests are uploaded as artifacts in a tar.xz to the build. In this case the tar.xz would be detected as binary and filtered out IIUC.

Ultimately the use case I'm presenting is something like having an Agent/LLM via jenkins MCP say:

oh, build #100 failed and from the Jenkins logs I see test A234 failed so crack open the tarball and look at the logs for A234 to investigate further. And oh btw build #99 didn't fail on the same test, so if you need to compare a successful run to a failed one look at the logs for A234 from build #99.

When kola tests fail, the pipeline uploads log bundle tarballs as Jenkins build artifacts. Add documentation on the artifact structure (journal.txt, console.txt, ignition.json, rerun/ directory) and what to look for when analyzing test failures. Note the current limitation that the Jenkins MCP Server Plugin does not yet support downloading build artifacts, and link to jenkinsci/mcp-server-plugin#42 as a potential future solution. Assisted-By: <anthropic/claude-opus-4.6>

dt-atmosic and others added 6 commits August 31, 2025 01:12

Fix objectMapper variable scope issue in test

18063d1

- Declare ObjectMapper inside lambda scope where it's used - Resolves compilation error in GetBuildWithoutArtifactsTest.java

Test fixes and cleanup

7b83969

- Use record for BuildArtifactResponse - Use TreePruner - spotless:apply

Fix JSON responses for getJobs and getBuildArtifacts

3a2d044

Update README for getBuildArtifact*

2cb1163

topikachu force-pushed the main branch from 1518513 to ecd8455 Compare September 29, 2025 01:18

Merge remote-tracking branch 'origin/main' into artifacts

9f195f2

dt-atmosic marked this pull request as ready for review October 20, 2025 23:20

dt-atmosic requested a review from a team as a code owner October 20, 2025 23:20

Improve code coverage for BuildArtifactsExtension

e10e41e

dt-atmosic added the enhancement For changelog: Minor enhancement. use `major-rfe` for changes to be highlighted label Oct 22, 2025

dt-atmosic requested review from olamy and topikachu October 22, 2025 23:14

olamy requested changes Oct 23, 2025

View reviewed changes

dt-atmosic added 2 commits May 30, 2026 01:43

jtnord mentioned this pull request Jul 8, 2026

Remove obsolete incremental config jenkinsci/warnings-ng-plugin#3382

Merged

6 tasks

dustymabe mentioned this pull request Jul 30, 2026

Add .agents/ instruction files for Chai Bot personas coreos/fedora-coreos-pipeline#1370

Merged

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dt-atmosic commented Sep 1, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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New Tools Added

Optimizations

Testing done

Submitter checklist

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dt-atmosic commented Oct 20, 2025

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dt-atmosic commented May 30, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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novinxy commented Jul 29, 2026

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dt-atmosic commented Sep 1, 2025 •

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