refactor(api): expose BaseConfig to tool and prompt handlers by manusa · Pull Request #916 · containers/kubernetes-mcp-server

manusa · 2026-03-12T09:18:23Z

Summary

PR #836 identified the need to expose the cluster provider strategy to toolsets. As some toolsets now call non-kube-API-server endpoints (e.g. Prometheus), they need to know the strategy to determine TLS and authentication configuration.

The approach in #836 expanded the GetTools() parameter, but this is evaluated at server startup — if the strategy changes via drop-in configuration support, toolsets would still see the stale value. Additionally, GetTools() should eventually take no parameters.

This PR takes an alternative approach: embed BaseConfig (instead of ExtendedConfigProvider) in ToolHandlerParams and PromptHandlerParams. Since BaseConfig already composes ClusterProvider (which provides GetClusterProviderStrategy()) and ExtendedConfigProvider, no new interface is needed. Toolsets can access the strategy at execution time — always reflecting the current configuration, even after a drop-in config reload.

Downstream consumers (e.g. openshift/openshift-mcp-server#124) can now call params.GetClusterProviderStrategy() in their tool handlers to determine TLS/auth behavior, following the same pattern Kiali already uses for its configuration.

Changes

pkg/api/toolsets.go / pkg/api/prompts.go — Embed BaseConfig instead of ExtendedConfigProvider in handler params
pkg/mcp/gosdk.go / pkg/mcp/prompts_gosdk.go — Update field assignment
pkg/mcp/mcp_config_provider_test.go — Behavioral tests verifying strategy access from tool/prompt handlers and config reload

Refs #836

Expose GetClusterProviderStrategy() to tool and prompt handlers at execution time via the new ConfigProvider interface. This allows toolsets to access the cluster provider strategy when invoked, rather than only at initialization through GetTools(). The approach is compatible with dynamic config reload — subsequent tool calls always see the current strategy value. Refs containers#836 Signed-off-by: Marc Nuri <marc@marcnuri.com>

matzew · 2026-03-12T10:20:02Z

+	GetClusterProviderStrategy() string
 	// GetProviderConfig returns the extended configuration for the given provider strategy.
 	// The boolean return value indicates whether the configuration was found.
 	GetProviderConfig(strategy string) (ExtendedConfig, bool)


we wanna change this to just Config? Or wanna keep the ExtendedConfig here and below?

Ah, I see that just actually retunrs the extended config - nervemind

ExtendedConfig is something else altogether.
The idea is that toolset implementers can provide custom Config entries in the toml file (hence the extended).

You can check how Kiali deals with this:

kubernetes-mcp-server/pkg/kiali/config.go

Lines 17 to 22 in 4f0ed3e

// Config holds Kiali toolset configuration

type Config struct {

Url string `toml:"url"`

Insecure bool `toml:"insecure,omitempty"`

CertificateAuthority string `toml:"certificate_authority,omitempty"`

}

By having an extended config, users can the provide specific values to configure the toolset:

[toolset_configs.kiali] url = "https://kiali.example/" certificate_authority = "ca.crt"

And then consumed through:

kubernetes-mcp-server/pkg/kiali/kiali.go

Lines 29 to 35 in b93fade

if cfg, ok := configProvider.GetToolsetConfig("kiali"); ok {

if kc, ok := cfg.(*Config); ok && kc != nil {

kiali.kialiURL = kc.Url

kiali.kialiInsecure = kc.Insecure

kiali.certificateAuthority = kc.CertificateAuthority

}

}

This basically makes the config extensible by toolsets in a decoupled way.

matzew · 2026-03-12T10:20:55Z

+// ConfigProvider provides read-only access to configuration from tool and prompt handlers.
+// This interface is embedded in ToolHandlerParams and PromptHandlerParams, allowing
+// toolsets to access configuration at execution time (not just at initialization).
+type ConfigProvider interface {


Rename to better communicate that this is the build-in config provider, rather than something that was intentially extending it?

I'm not sure I'm following, do you mean to rename to BuiltinConfigProvider?
Basically the api interface here is just exposing the Config values (those we've decided to make public) instead of completely exposing the StaticConfig.
Any Config value that needs to be accessed by toolsets would need to be explicitly exposed here.

matzew · 2026-03-12T10:29:18Z

LGTM

Cali0707

LGTM

Cali0707 · 2026-03-12T18:50:16Z

+// toolsets to access configuration at execution time (not just at initialization).
+type ConfigProvider interface {
+	// GetClusterProviderStrategy returns the cluster provider strategy (e.g. "kubeconfig", "in-cluster").
+	GetClusterProviderStrategy() string


@manusa is there any concern about this method being duplicated between this interface and the ClusterProvider interface which also goes into BaseConfig ?

This all compiles fine and is concretely backed by a single func, so i guess maybe it is fine?

Yes, there is :) I had that flagged.

Another option is to revert the changes to the api package, and actually expose the api.BaseConfig interface instead of api.ConfigProvider.

I'll add this as a second commit and let you folks decide what's best (@matzew @Cali0707)

Replace the ConfigProvider interface with the existing BaseConfig interface in ToolHandlerParams and PromptHandlerParams. This avoids duplicating GetClusterProviderStrategy() across two interfaces and reuses the already composed BaseConfig which includes ClusterProvider and ExtendedConfigProvider. Reverts changes to pkg/api/config.go and pkg/kiali/kiali.go since no new interface is needed. Refs containers#836 Signed-off-by: Marc Nuri <marc@marcnuri.com>

matzew · 2026-03-13T06:45:15Z

LGTM

I think renaming of ExtendedConfigProvider to BaseConfig is fine. Should the PR title cover that too?

manusa · 2026-03-13T08:08:47Z

LGTM

I think renaming of ExtendedConfigProvider to BaseConfig is fine. Should the PR title cover that too?

🤦 forgot to update the PR title and description. Thanks for catching that.

Technically it's not renaming but exposing BaseConfig as part of the tools and prompt handler params.

Cali0707

LGTM, thanks @manusa !

…ers#916) * refactor(api): rename ExtendedConfigProvider to ConfigProvider Expose GetClusterProviderStrategy() to tool and prompt handlers at execution time via the new ConfigProvider interface. This allows toolsets to access the cluster provider strategy when invoked, rather than only at initialization through GetTools(). The approach is compatible with dynamic config reload — subsequent tool calls always see the current strategy value. Refs containers#836 Signed-off-by: Marc Nuri <marc@marcnuri.com> * refactor(api): expose BaseConfig to tool and prompt handlers Replace the ConfigProvider interface with the existing BaseConfig interface in ToolHandlerParams and PromptHandlerParams. This avoids duplicating GetClusterProviderStrategy() across two interfaces and reuses the already composed BaseConfig which includes ClusterProvider and ExtendedConfigProvider. Reverts changes to pkg/api/config.go and pkg/kiali/kiali.go since no new interface is needed. Refs containers#836 Signed-off-by: Marc Nuri <marc@marcnuri.com> --------- Signed-off-by: Marc Nuri <marc@marcnuri.com>

Signed-off-by: Matthias Wessendorf <mwessend@redhat.com>

manusa requested a review from Cali0707 March 12, 2026 09:18

manusa added this to the 0.1.0 milestone Mar 12, 2026

manusa force-pushed the refactor/rename-extended-config-provider-to-config-provider branch from 1041165 to b93fade Compare March 12, 2026 09:20

matzew reviewed Mar 12, 2026

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Cali0707 approved these changes Mar 12, 2026

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manusa requested review from Cali0707 and matzew March 13, 2026 04:46

manusa changed the title ~~refactor(api): rename ExtendedConfigProvider to ConfigProvider~~ refactor(api): expose BaseConfig to tool and prompt handlers Mar 13, 2026

Cali0707 approved these changes Mar 13, 2026

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matzew merged commit d6a661c into containers:main Mar 13, 2026
8 checks passed

manusa deleted the refactor/rename-extended-config-provider-to-config-provider branch March 13, 2026 14:29

matzew added a commit to matzew/kubernetes-mcp-server that referenced this pull request Mar 13, 2026

Netedge using BaseConfig, after containers#916

1da5581

Signed-off-by: Matthias Wessendorf <mwessend@redhat.com>

matzew added a commit to matzew/kubernetes-mcp-server that referenced this pull request Mar 13, 2026

Netedge using BaseConfig, after containers#916

4d7101f

Signed-off-by: Matthias Wessendorf <mwessend@redhat.com>

manusa mentioned this pull request Mar 18, 2026

refactor: expose cluster provider strategy to toolsets #836

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refactor(api): expose BaseConfig to tool and prompt handlers#916

refactor(api): expose BaseConfig to tool and prompt handlers#916
matzew merged 2 commits intocontainers:mainfrom
marcnuri-forks:refactor/rename-extended-config-provider-to-config-provider

manusa commented Mar 12, 2026 •

edited

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	// Config holds Kiali toolset configuration
	type Config struct {
	Url string `toml:"url"`
	Insecure bool `toml:"insecure,omitempty"`
	CertificateAuthority string `toml:"certificate_authority,omitempty"`
	}

	if cfg, ok := configProvider.GetToolsetConfig("kiali"); ok {
	if kc, ok := cfg.(*Config); ok && kc != nil {
	kiali.kialiURL = kc.Url
	kiali.kialiInsecure = kc.Insecure
	kiali.certificateAuthority = kc.CertificateAuthority
	}
	}

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manusa commented Mar 12, 2026 •

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