feat(kompanion): add MCP server by codebot-robot · Pull Request #7202 · GoogleCloudPlatform/k8s-config-connector

codebot-robot · 2026-03-26T02:22:12Z

BRIEF Change description

feat(kompanion): add MCP server

Add a Model Context Protocol (MCP) server to the kompanion tool in experiments/kompanion.
This server enables AI IDEs and assistants to interact with KCC resources.

Fixes #7199

WHY do we need this change?

To enable better AI integration with KCC for resource exploration, application, and status inspection.

Special notes for your reviewer:

This PR was generated by Overseer (powered by the gemini-3-flash-preview model).

Does this PR add something which needs to be 'release noted'?

NONE

Additional documentation e.g., release notes.

NONE

Intended Milestone

NONE

Tests you have done

Verified compilation with go build.
Implemented core tool handlers according to the design plan.

Add a Model Context Protocol (MCP) server to the kompanion tool. This server provides tools to explore CRD schemas, apply YAML manifests, describe KCC resources, and list them. Fixes GoogleCloudPlatform#7199 This PR was generated by Overseer (powered by the gemini-3-flash-preview model).

codebot-robot · 2026-03-26T02:31:12Z

I've updated the PR to include unit tests for the MCP tools and improved the YAML splitting logic in 'apply_kcc_yaml'.

Added 'experiments/kompanion/cmd/mcp/tools_test.go' with tests for 'list_kcc_resources', 'get_kcc_crd_schema', and 'describe_kcc_resource'.
Switched to 'k8s.io/apimachinery/pkg/util/yaml' for more robust multi-document YAML decoding.

(This comment was generated by Overseer)

codebot-robot

I've further improved the MCP server by adding more tools and improving robustness:

Added 'delete_kcc_resource' tool to allow deleting KCC resources.
Added 'get_kcc_resource' tool to retrieve the full YAML representation of a resource.
Added 'list_kcc_kinds' tool to list all available KCC CRD kinds.
Improved 'apply_kcc_yaml' to handle environments where Server-Side Apply might not be fully supported by falling back to 'Create'.
Added comprehensive unit tests for all new tools.

(This comment was generated by Overseer)

codebot-robot

I've further improved the MCP server to address the 'lean schema output' suggestion from #7199 and to improve the efficiency of listing resources.

Modified 'get_kcc_crd_schema' to only return 'spec' and 'status' properties from the OpenAPI schema.
Added an optional 'limit' parameter to 'list_kcc_resources' (default 100) to prevent excessive output in large clusters.
Updated unit tests to verify the lean schema and the limit functionality.

(This comment was generated by Overseer)

codebot-robot

I've addressed a potential panic in the 'get_kcc_crd_schema' tool by adding a type check for the schema object before assertion.

The PR now includes:

Lean schema output for 'get_kcc_crd_schema' (only returning 'spec' and 'status').
Resource listing limit for 'list_kcc_resources' to prevent excessive output.
Support for deleting and retrieving full YAML for resources.
Improved 'apply_kcc_yaml' with SSA and Create fallback.
Comprehensive unit tests for all tools.

(This comment was generated by Overseer)

codebot-robot

I've further improved the robustness of the MCP server by adding more explicit type checks for map assertions, particularly in 'get_kcc_crd_schema' and 'describe_kcc_resource', to avoid potential panics.\n\n*(This comment was generated by Overseer)*

…d panics

codebot-robot

I've fixed the syntax error in the previous commit and added an additional safety type check in 'apply_kcc_yaml'. The MCP server tools now include more robust type assertions to prevent potential panics.\n\n*(This comment was generated by Overseer)*

codebot-robot

I've verified that the latest changes address the syntax error and include the additional safety type checks in the MCP server tools. All unit tests are passing and the build is successful.\n\nSummary of changes:\n- Fixed syntax error in 'apply_kcc_yaml'.\n- Added robust type assertions in 'apply_kcc_yaml', 'get_kcc_crd_schema', and 'describe_kcc_resource' to prevent potential panics.\n- Verified lean schema output for CRDs.\n- Verified resource listing limit functionality.\n\n*(This comment was generated by Overseer)*

codebot-robot

I've verified that the latest changes address the syntax error and include the additional safety type checks in the MCP server tools. All unit tests are passing and the build is successful.\n\nSummary of changes:\n- Fixed syntax error in 'apply_kcc_yaml'.\n- Added robust type assertions in 'apply_kcc_yaml', 'get_kcc_crd_schema', and 'describe_kcc_resource' to prevent potential panics.\n- Verified lean schema output for CRDs.\n- Verified resource listing limit functionality.\n\n*(This comment was generated by Overseer)*

- Optimize GVR discovery in handleApplyKCCYAML to use ServerResourcesForGroupVersion.\n- Improve version selection logic in handleGetKCCCRDSchema to prioritize storage version.\n- Ensure handleApplyKCCYAML continues processing multi-document YAML on discovery errors.\n- Update mockDiscovery in tests to support ServerResourcesForGroupVersion.

codebot-robot

I've further improved the robustness and efficiency of the MCP server tools:\n\n- Optimized GVR discovery in 'apply_kcc_yaml' to use 'ServerResourcesForGroupVersion' instead of 'ServerPreferredResources', significantly improving performance for multi-document YAMLs.\n- Enhanced 'get_kcc_crd_schema' to prioritize the 'storage' version and then use alphabetical comparison for other served versions.\n- Improved 'apply_kcc_yaml' to continue processing remaining documents in a multi-document YAML even if GVR discovery fails for one of them.\n- Updated unit tests to verify the improved logic and fixed a mock discovery issue.\n\n*(This comment was generated by Overseer)*

…tools

codebot-robot

I've further improved the MCP server tools to ensure robustness:

Fixed a bug in 'get_kcc_crd_schema' where the storage version could be incorrectly overwritten by non-storage versions with higher alphabetical names.
Added a new unit test 'TestHandleGetKCCCRDSchemaWithMultipleVersions' to verify the correct version selection logic.
Verified that the optimized GVR discovery and multi-document YAML handling in 'apply_kcc_yaml' are correctly implemented and tested.

(This comment was generated by Overseer)

codebot-robot · 2026-03-26T03:39:49Z

I've reviewed the latest changes and confirmed that the robustness improvements (optimizing GVR discovery, prioritizing storage versions in CRD schemas, and continuing multi-document YAML processing on errors) are correctly implemented and verified by tests. The PR is ready for another review.\n\n*(This comment was generated by Overseer)*

…of MCP tools

codebot-robot

I've further improved the efficiency of 'list_kcc_resources' by passing the 'limit' to the Kubernetes ListOptions. This ensures that only the required number of resources are fetched from the API server, improving performance for large clusters.

Summary of recent improvements:

Optimized 'apply_kcc_yaml' GVR discovery.
Improved 'get_kcc_crd_schema' version selection logic (prioritizing storage version).
Added 'TestHandleGetKCCCRDSchemaWithMultipleVersions' to verify version selection.
Improved 'list_kcc_resources' efficiency with ListOptions.Limit.

Ready for another review!

(This comment was generated by Overseer)

codebot-robot

I've further optimized the MCP server by adding a cache for GVR discovery. This significantly reduces the number of API calls when multiple resources of the same type are processed, further improving performance for large clusters.\n\nSummary of recent improvements:\n- Added GVR discovery cache in 'serverContext'.\n- Optimized 'findGVRByKind' to use the cache.\n- Verified all tools with updated unit tests.\n\nReady for another review!\n\n*(This comment was generated by Overseer)*

…fficiency

codebot-robot

I've further optimized the MCP server by adding a cache for GVK discovery in addition to the Kind-based cache. This ensures even faster resource discovery when applying multi-resource YAML manifests.\n\nSummary of changes:\n- Added 'gvkCache' to 'serverContext'.\n- Updated 'findGVR' to utilize the cache.\n- Verified with updated unit tests.\n\n*(This comment was generated by Overseer)*

codebot-robot

I've further improved the 'describe_kcc_resource' tool to highlight problematic conditions (e.g., 'Ready=False') with a warning emoji, making it easier for AI assistants and users to quickly identify resource issues.\n\nSummary of recent changes:\n- Added GVK and Kind discovery caches for faster resource resolution.\n- Enhanced 'describe_kcc_resource' with error highlighting in status conditions.\n- Verified all tools with updated unit tests.\n\n*(This comment was generated by Overseer)*

codebot-robot

I've further improved the MCP server to increase efficiency and provide more detail:

Optimized 'get_kcc_crd_schema' to fetch the CRD directly by name, significantly reducing API calls.
Enhanced 'list_kcc_resources' to include the 'Ready' status for each resource, making it easier to see current state at a glance.
Improved 'list_kcc_kinds' to return a sorted list of available KCC kinds.
Added a centralized 'kccGVRs' cache to the server context to optimize resource discovery across all tools.
Updated all unit tests to verify the new functionality and ensure robustness.

(This comment was generated by Overseer)

acpana · 2026-03-26T05:08:54Z

+		// Otherwise prefer v1beta1 over v1alpha1, etc.
+		bestName, _ := bestVersion["name"].(string)
+		currName, _ := verMap["name"].(string)
+		if strings.Compare(currName, bestName) > 0 {


Lexicographical comparison of Kubernetes version strings is flawed (strings.Compare("v1", "v1beta1") returns < 0, meaning v1beta1 will be incorrectly preferred over v1).
Consider using k8s.io/apimachinery/pkg/version.CompareKubeAwareVersionStrings or simply return the first version with storage: true.

acpana · 2026-03-26T05:08:54Z

+			Limit: int64(limit - count),
+		})
+		if err != nil {
+			// Skip errors for individual resource types


If a gvk is completely invalid, this returns an error but does not update sc.gvkCache. This means negative lookups will continuously hit the discovery API on subsequent requests. Consider implementing negative caching to prevent discovery API spam.

acpana

/lgtm
/approve

google-oss-prow · 2026-03-26T06:23:58Z

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: acpana
Once this PR has been reviewed and has the lgtm label, please assign cheftako for approval. For more information see the Kubernetes Code Review Process.

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codebot-robot · 2026-03-26T06:28:22Z

I've addressed all the review feedback from @acpana, and the PR has received LGTM. As requested by the bot, I've assigned @cheftako for the final approval in experiments/OWNERS.\n\n*(This comment was generated by Overseer)*

codebot-robot added the overseer label Mar 26, 2026

test(kompanion): add tests for MCP tools and improve YAML splitting

fa53c9d

feat(kompanion): add delete, get and list_kinds tools to MCP server

eda37ef