Hoist _meta onto CustomizationBase so every customization type carries provider metadata uniformly

CHANGELOG.md

@@ -32,6 +32,13 @@ changes accumulate. Track in-flight protocol changes via PRs touching
   functionality.
 - `changeset/filesReviewedChanged` action for servers to update the `reviewed`
   flag of one or more changeset files.
+- Hoisted the optional `_meta` provider-metadata slot from `AgentCustomization`
+  up to the shared `CustomizationBase`, so every customization type
+  (`PluginCustomization`, `ClientPluginCustomization`, `DirectoryCustomization`,
+  `SkillCustomization`, `PromptCustomization`, `RuleCustomization`,
+  `HookCustomization`, and `McpServerCustomization`) now carries the same
+  provider-specific escape hatch. Wire-compatible: `AgentCustomization` still
+  exposes `_meta`, now by inheritance.
 - Optional `version` field on `PluginCustomization` (inherited by
   `ClientPluginCustomization`), carrying the plugin's semver sourced from the
   Open Plugins manifest's optional `version`. Provenance / display only; absent

clients/go/CHANGELOG.md

@@ -32,6 +32,11 @@ Implements AHP 0.5.2.
   functionality.
 - `changeset/filesReviewedChanged` action for servers to update the `Reviewed`
   flag of one or more changeset files.
+- Optional `Meta` (wire `_meta`) provider-metadata field on every customization
+  type, moved from `AgentCustomization` up to the shared customization base so
+  `PluginCustomization`, `ClientPluginCustomization`, `DirectoryCustomization`,
+  `SkillCustomization`, `PromptCustomization`, `RuleCustomization`,
+  `HookCustomization`, and `McpServerCustomization` all carry it.
 - Optional `ServerInfo` on `InitializeResult` and `ClientInfo` on
   `InitializeParams`, each an `Implementation` struct (`Name`, optional
   `Version`, optional `Title`), identifying the implementation and build behind

clients/go/ahptypes/state.generated.go

@@ -2087,6 +2087,12 @@ type PluginCustomization struct {
 	// in an inline `mcpServers` block of a `plugins.json` manifest).
 	// Absent when the customization covers the whole resource.
 	Range *TextRange `json:"range,omitempty"`
+	// Additional provider-specific metadata for this customization.
+	//
+	// Mirrors the MCP `_meta` convention. Optional and opaque to the
+	// protocol; producers and consumers agree on its contents
+	// out-of-band.
+	Meta map[string]json.RawMessage `json:"_meta,omitempty"`
 	// Whether this container is currently enabled.
 	Enabled bool `json:"enabled"`
 	// `clientId` of the client that contributed this container. Absent for
@@ -2142,6 +2148,12 @@ type ClientPluginCustomization struct {
 	// in an inline `mcpServers` block of a `plugins.json` manifest).
 	// Absent when the customization covers the whole resource.
 	Range *TextRange `json:"range,omitempty"`
+	// Additional provider-specific metadata for this customization.
+	//
+	// Mirrors the MCP `_meta` convention. Optional and opaque to the
+	// protocol; producers and consumers agree on its contents
+	// out-of-band.
+	Meta map[string]json.RawMessage `json:"_meta,omitempty"`
 	// Whether this container is currently enabled.
 	Enabled bool `json:"enabled"`
 	// `clientId` of the client that contributed this container. Absent for
@@ -2199,6 +2211,12 @@ type DirectoryCustomization struct {
 	// in an inline `mcpServers` block of a `plugins.json` manifest).
 	// Absent when the customization covers the whole resource.
 	Range *TextRange `json:"range,omitempty"`
+	// Additional provider-specific metadata for this customization.
+	//
+	// Mirrors the MCP `_meta` convention. Optional and opaque to the
+	// protocol; producers and consumers agree on its contents
+	// out-of-band.
+	Meta map[string]json.RawMessage `json:"_meta,omitempty"`
 	// Whether this container is currently enabled.
 	Enabled bool `json:"enabled"`
 	// `clientId` of the client that contributed this container. Absent for
@@ -2247,6 +2265,12 @@ type AgentCustomization struct {
 	// in an inline `mcpServers` block of a `plugins.json` manifest).
 	// Absent when the customization covers the whole resource.
 	Range *TextRange `json:"range,omitempty"`
+	// Additional provider-specific metadata for this customization.
+	//
+	// Mirrors the MCP `_meta` convention. Optional and opaque to the
+	// protocol; producers and consumers agree on its contents
+	// out-of-band.
+	Meta map[string]json.RawMessage `json:"_meta,omitempty"`
 	// Whether this child is individually enabled. Absent means enabled, so a
 	// producer only needs to set it to surface a child that exists but is
 	// turned off on its own.
@@ -2283,10 +2307,6 @@ type AgentCustomization struct {
 	// in a picker); it remains available for the agent to auto-delegate
 	// to. Absent or `false` means the user may select it.
 	DisableUserInvocation *bool `json:"disableUserInvocation,omitempty"`
-	// Additional provider-specific metadata for this custom agent.
-	//
-	// Mirrors the MCP `_meta` convention.
-	Meta map[string]json.RawMessage `json:"_meta,omitempty"`
 }
 
 // A skill contributed by a plugin or directory.
@@ -2317,6 +2337,12 @@ type SkillCustomization struct {
 	// in an inline `mcpServers` block of a `plugins.json` manifest).
 	// Absent when the customization covers the whole resource.
 	Range *TextRange `json:"range,omitempty"`
+	// Additional provider-specific metadata for this customization.
+	//
+	// Mirrors the MCP `_meta` convention. Optional and opaque to the
+	// protocol; producers and consumers agree on its contents
+	// out-of-band.
+	Meta map[string]json.RawMessage `json:"_meta,omitempty"`
 	// Whether this child is individually enabled. Absent means enabled, so a
 	// producer only needs to set it to surface a child that exists but is
 	// turned off on its own.
@@ -2366,6 +2392,12 @@ type PromptCustomization struct {
 	// in an inline `mcpServers` block of a `plugins.json` manifest).
 	// Absent when the customization covers the whole resource.
 	Range *TextRange `json:"range,omitempty"`
+	// Additional provider-specific metadata for this customization.
+	//
+	// Mirrors the MCP `_meta` convention. Optional and opaque to the
+	// protocol; producers and consumers agree on its contents
+	// out-of-band.
+	Meta map[string]json.RawMessage `json:"_meta,omitempty"`
 	// Whether this child is individually enabled. Absent means enabled, so a
 	// producer only needs to set it to surface a child that exists but is
 	// turned off on its own.
@@ -2414,6 +2446,12 @@ type RuleCustomization struct {
 	// in an inline `mcpServers` block of a `plugins.json` manifest).
 	// Absent when the customization covers the whole resource.
 	Range *TextRange `json:"range,omitempty"`
+	// Additional provider-specific metadata for this customization.
+	//
+	// Mirrors the MCP `_meta` convention. Optional and opaque to the
+	// protocol; producers and consumers agree on its contents
+	// out-of-band.
+	Meta map[string]json.RawMessage `json:"_meta,omitempty"`
 	// Whether this child is individually enabled. Absent means enabled, so a
 	// producer only needs to set it to surface a child that exists but is
 	// turned off on its own.
@@ -2461,6 +2499,12 @@ type HookCustomization struct {
 	// in an inline `mcpServers` block of a `plugins.json` manifest).
 	// Absent when the customization covers the whole resource.
 	Range *TextRange `json:"range,omitempty"`
+	// Additional provider-specific metadata for this customization.
+	//
+	// Mirrors the MCP `_meta` convention. Optional and opaque to the
+	// protocol; producers and consumers agree on its contents
+	// out-of-band.
+	Meta map[string]json.RawMessage `json:"_meta,omitempty"`
 	// Whether this child is individually enabled. Absent means enabled, so a
 	// producer only needs to set it to surface a child that exists but is
 	// turned off on its own.
@@ -2505,8 +2549,14 @@ type McpServerCustomization struct {
 	// customization is a subset of a larger file (for example, one entry
 	// in an inline `mcpServers` block of a `plugins.json` manifest).
 	// Absent when the customization covers the whole resource.
-	Range *TextRange        `json:"range,omitempty"`
-	Type  CustomizationType `json:"type"`
+	Range *TextRange `json:"range,omitempty"`
+	// Additional provider-specific metadata for this customization.
+	//
+	// Mirrors the MCP `_meta` convention. Optional and opaque to the
+	// protocol; producers and consumers agree on its contents
+	// out-of-band.
+	Meta map[string]json.RawMessage `json:"_meta,omitempty"`
+	Type CustomizationType          `json:"type"`
 	// Whether this MCP server is currently enabled.
 	Enabled bool `json:"enabled"`
 	// Current lifecycle state of the MCP server.

clients/kotlin/CHANGELOG.md

@@ -33,6 +33,11 @@ Implements AHP 0.5.2.
   functionality.
 - `changeset/filesReviewedChanged` action for servers to update the `reviewed`
   flag of one or more changeset files.
+- Optional `meta` (wire `_meta`) provider-metadata field on every customization
+  type, moved from `AgentCustomization` up to the shared customization base so
+  `PluginCustomization`, `ClientPluginCustomization`, `DirectoryCustomization`,
+  `SkillCustomization`, `PromptCustomization`, `RuleCustomization`,
+  `HookCustomization`, and `McpServerCustomization` all carry it.
 - Optional `serverInfo` on `InitializeResult` and `clientInfo` on
   `InitializeParams`, each an `Implementation` (`name`, optional `version`,
   optional `title`), identifying the implementation and build behind either side

clients/kotlin/src/main/kotlin/com/microsoft/agenthostprotocol/generated/State.generated.kt

@@ -2953,6 +2953,15 @@ data class PluginCustomization(
      * Absent when the customization covers the whole resource.
      */
     val range: TextRange? = null,
+    /**
+     * Additional provider-specific metadata for this customization.
+     *
+     * Mirrors the MCP `_meta` convention. Optional and opaque to the
+     * protocol; producers and consumers agree on its contents
+     * out-of-band.
+     */
+    @SerialName("_meta")
+    val meta: Map<String, JsonElement>? = null,
     /**
      * Whether this container is currently enabled.
      */
@@ -3020,6 +3029,15 @@ data class ClientPluginCustomization(
      * Absent when the customization covers the whole resource.
      */
     val range: TextRange? = null,
+    /**
+     * Additional provider-specific metadata for this customization.
+     *
+     * Mirrors the MCP `_meta` convention. Optional and opaque to the
+     * protocol; producers and consumers agree on its contents
+     * out-of-band.
+     */
+    @SerialName("_meta")
+    val meta: Map<String, JsonElement>? = null,
     /**
      * Whether this container is currently enabled.
      */
@@ -3091,6 +3109,15 @@ data class DirectoryCustomization(
      * Absent when the customization covers the whole resource.
      */
     val range: TextRange? = null,
+    /**
+     * Additional provider-specific metadata for this customization.
+     *
+     * Mirrors the MCP `_meta` convention. Optional and opaque to the
+     * protocol; producers and consumers agree on its contents
+     * out-of-band.
+     */
+    @SerialName("_meta")
+    val meta: Map<String, JsonElement>? = null,
     /**
      * Whether this container is currently enabled.
      */
@@ -3157,6 +3184,15 @@ data class AgentCustomization(
      * Absent when the customization covers the whole resource.
      */
     val range: TextRange? = null,
+    /**
+     * Additional provider-specific metadata for this customization.
+     *
+     * Mirrors the MCP `_meta` convention. Optional and opaque to the
+     * protocol; producers and consumers agree on its contents
+     * out-of-band.
+     */
+    @SerialName("_meta")
+    val meta: Map<String, JsonElement>? = null,
     /**
      * Whether this child is individually enabled. Absent means enabled, so a
      * producer only needs to set it to surface a child that exists but is
@@ -3204,14 +3240,7 @@ data class AgentCustomization(
      * in a picker); it remains available for the agent to auto-delegate
      * to. Absent or `false` means the user may select it.
      */
-    val disableUserInvocation: Boolean? = null,
-    /**
-     * Additional provider-specific metadata for this custom agent.
-     *
-     * Mirrors the MCP `_meta` convention.
-     */
-    @SerialName("_meta")
-    val meta: Map<String, JsonElement>? = null
+    val disableUserInvocation: Boolean? = null
 )
 
 @Serializable
@@ -3247,6 +3276,15 @@ data class SkillCustomization(
      * Absent when the customization covers the whole resource.
      */
     val range: TextRange? = null,
+    /**
+     * Additional provider-specific metadata for this customization.
+     *
+     * Mirrors the MCP `_meta` convention. Optional and opaque to the
+     * protocol; producers and consumers agree on its contents
+     * out-of-band.
+     */
+    @SerialName("_meta")
+    val meta: Map<String, JsonElement>? = null,
     /**
      * Whether this child is individually enabled. Absent means enabled, so a
      * producer only needs to set it to surface a child that exists but is
@@ -3314,6 +3352,15 @@ data class PromptCustomization(
      * Absent when the customization covers the whole resource.
      */
     val range: TextRange? = null,
+    /**
+     * Additional provider-specific metadata for this customization.
+     *
+     * Mirrors the MCP `_meta` convention. Optional and opaque to the
+     * protocol; producers and consumers agree on its contents
+     * out-of-band.
+     */
+    @SerialName("_meta")
+    val meta: Map<String, JsonElement>? = null,
     /**
      * Whether this child is individually enabled. Absent means enabled, so a
      * producer only needs to set it to surface a child that exists but is
@@ -3368,6 +3415,15 @@ data class RuleCustomization(
      * Absent when the customization covers the whole resource.
      */
     val range: TextRange? = null,
+    /**
+     * Additional provider-specific metadata for this customization.
+     *
+     * Mirrors the MCP `_meta` convention. Optional and opaque to the
+     * protocol; producers and consumers agree on its contents
+     * out-of-band.
+     */
+    @SerialName("_meta")
+    val meta: Map<String, JsonElement>? = null,
     /**
      * Whether this child is individually enabled. Absent means enabled, so a
      * producer only needs to set it to surface a child that exists but is
@@ -3433,6 +3489,15 @@ data class HookCustomization(
      * Absent when the customization covers the whole resource.
      */
     val range: TextRange? = null,
+    /**
+     * Additional provider-specific metadata for this customization.
+     *
+     * Mirrors the MCP `_meta` convention. Optional and opaque to the
+     * protocol; producers and consumers agree on its contents
+     * out-of-band.
+     */
+    @SerialName("_meta")
+    val meta: Map<String, JsonElement>? = null,
     /**
      * Whether this child is individually enabled. Absent means enabled, so a
      * producer only needs to set it to surface a child that exists but is
@@ -3483,6 +3548,15 @@ data class McpServerCustomization(
      * Absent when the customization covers the whole resource.
      */
     val range: TextRange? = null,
+    /**
+     * Additional provider-specific metadata for this customization.
+     *
+     * Mirrors the MCP `_meta` convention. Optional and opaque to the
+     * protocol; producers and consumers agree on its contents
+     * out-of-band.
+     */
+    @SerialName("_meta")
+    val meta: Map<String, JsonElement>? = null,
     val type: CustomizationType,
     /**
      * Whether this MCP server is currently enabled.

clients/rust/CHANGELOG.md

@@ -34,6 +34,11 @@ Implements AHP 0.5.2.
   functionality.
 - `changeset/filesReviewedChanged` action for servers to update the `reviewed`
   flag of one or more changeset files.
+- Optional `meta` (wire `_meta`) provider-metadata field on every customization
+  type, moved from `AgentCustomization` up to the shared customization base so
+  `PluginCustomization`, `ClientPluginCustomization`, `DirectoryCustomization`,
+  `SkillCustomization`, `PromptCustomization`, `RuleCustomization`,
+  `HookCustomization`, and `McpServerCustomization` all carry it.
 - Optional `server_info` on `InitializeResult` and `client_info` on
   `InitializeParams`, each an `Implementation` struct (`name`, optional
   `version`, optional `title`), identifying the implementation and build behind