diff --git a/README.md b/README.md
index 1b7adfe..b128307 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ exports `activate(ctx)`.
 - [Windows](docs/windows.md): opening plugin layouts in detached OS windows.
 - [Services](docs/services.md): workspace, tasks, tooling, events, config, terminal and windows facades.
 - [Packaging And Distribution](docs/packaging-distribution.md): build output, archive layout, hot reload and dependency rules.
-- [Codex Skills And IdeA Plugins](docs/codex-skills-and-idea-plugins.md): separate runtime install from Codex skill discovery.
+- [Codex Skills And IdeA Plugins](docs/codex-skills-and-idea-plugins.md): separate IdeA-native plugin skills from Codex plugin discovery.
 
 The installable example lives in [`examples/hello-plugin`](examples/hello-plugin).
 It demonstrates a menu command, storage, background-task feedback, a React layout
diff --git a/docs/codex-skills-and-idea-plugins.md b/docs/codex-skills-and-idea-plugins.md
index 59c1693..8767531 100644
--- a/docs/codex-skills-and-idea-plugins.md
+++ b/docs/codex-skills-and-idea-plugins.md
@@ -1,12 +1,20 @@
 # Codex Skills And IdeA Plugins
 
-IdeA runtime plugins and Codex plugins are separate installation and discovery
-systems.
+IdeA runtime plugins, IdeA-native plugin skills and Codex plugins are distinct
+installation and discovery systems.
 
 An IdeA runtime plugin is described by `idea-plugin.json`. Installing it through
-IdeA makes its IdeA runtime contributions available: menus, menu items, slash
-commands, layouts, MCP servers and runtime services declared by the IdeA plugin
-manifest.
+IdeA makes its global runtime package available. Project settings then decide
+which installed plugins are enabled for a project, and agent settings decide
+which plugin skills and plugin MCP tools are assigned to each agent.
+
+An IdeA-native plugin skill is declared in `idea-plugin.json` under
+`contributes.skills`. Its body is a package-relative Markdown file such as
+`skills/<name>/SKILL.md`. When the plugin is enabled for a project and the skill
+is assigned to an agent, IdeA injects the skill affordance into that agent's
+skill catalogue and serves the body through `idea_skill_read`. This is not
+Codex-specific; it is projected by IdeA for every harness that supports IdeA
+capabilities, including Claude Code, Codex, OpenCode local and OpenCode cloud.
 
 A Codex plugin is described by `.codex-plugin/plugin.json`. Its `skills` entry
 points Codex at skill directories such as `skills/*/SKILL.md`. This metadata is
@@ -15,27 +23,29 @@ loading.
 
 ## Normative Behavior
 
+- Installing or reloading an IdeA plugin makes the package available globally,
+  but does not automatically enable it in every project.
+- Enabling a plugin for a project does not automatically assign every skill or
+  MCP tool to every agent.
+- A plugin skill becomes visible to an agent only when the plugin is enabled for
+  the project and that skill is assigned to that agent.
 - Installing or reloading an IdeA plugin does not automatically install a bundled
-  Codex plugin.
-- Installing or reloading an IdeA plugin does not automatically make bundled
-  Codex skills available to agents in the current project.
-- Installing or reloading an IdeA plugin does not automatically make bundled
-  Codex skills available to agents in other projects.
-- No `idea-plugin.json` manifest field currently declares Codex skills for IdeA
-  agent assignment.
-- Bundling `.codex-plugin/plugin.json` and `skills/*/SKILL.md` inside an IdeA
-  plugin package is allowed as distribution content, but it is inert for IdeA
-  runtime plugin loading unless a separate bridge explicitly consumes it.
+  Codex plugin, and `.codex-plugin/plugin.json` remains inert for IdeA-native
+  plugin loading unless a separate bridge explicitly consumes it.
+- Bundling `.codex-plugin/plugin.json` is still allowed as distribution content
+  for Codex-specific workflows, but it is not the multi-harness IdeA contract.
 
-## Required Mechanism
+## Required Mechanisms
 
-If a plugin needs Codex skills to be available to agents, install the Codex
-plugin through the Codex plugin mechanism for the intended scope, then assign or
-enable those skills for the relevant agents according to Codex/IdeA agent
-configuration.
+For multi-harness IdeA agent skills, declare `contributes.skills` in
+`idea-plugin.json`, ship the referenced Markdown files inside the package,
+install the plugin in IdeA, enable it in the target project, and assign the
+skills to the target agents.
 
-Do not rely on IdeA plugin installation as a cross-project skill propagation
-mechanism. Cross-project skill availability needs an explicit product contract
-covering scope, provenance, permissions, uninstall behavior, hot reload,
-collisions and security. Until that bridge exists, document and perform Codex
-skill installation separately from IdeA runtime plugin installation.
+For Codex-specific plugin skills, install the Codex plugin through the Codex
+plugin mechanism for the intended scope, then assign or enable those skills
+according to Codex/IdeA agent configuration.
+
+Do not rely on `.codex-plugin/plugin.json` as a cross-harness skill propagation
+mechanism. Cross-harness plugin skill availability is driven by
+`idea-plugin.json` and IdeA project/agent assignments.
diff --git a/docs/manifest.md b/docs/manifest.md
index ebaf2de..56f2727 100644
--- a/docs/manifest.md
+++ b/docs/manifest.md
@@ -143,6 +143,40 @@ development loop.
 
 ## Contributions
 
+`contributes.skills` declares read-only agent skills shipped inside the IdeA
+plugin package. These skills are IdeA-native: IdeA can expose them in project
+plugin settings, assign them to agents, inject them into the agent skill
+catalogue, and serve their Markdown body through `idea_skill_read` for every
+supported harness that receives IdeA capabilities, including Claude Code,
+Codex, OpenCode local and OpenCode cloud.
+
+```json
+{
+  "contributes": {
+    "skills": [
+      {
+        "id": "unity.build-debug",
+        "name": "unity-build-debug",
+        "description": "Diagnose Unity build failures.",
+        "kind": "workflow",
+        "path": "skills/unity-build-debug/SKILL.md"
+      }
+    ]
+  }
+}
+```
+
+Skill contribution rules:
+
+- `id` is stable within the plugin and is used by project/agent assignments.
+- `name` is the agent-facing name shown in the injected skill catalogue and
+  accepted by `idea_skill_read`.
+- `description` is the short affordance shown before the agent loads the skill.
+- `kind` defaults to `"workflow"`; `"reference"` is also supported.
+- `path` must be a package-relative Markdown file path ending in `.md`.
+- Installing a plugin globally is not enough: a project must enable the plugin,
+  then assign the skill to the target agent.
+
 `contributes.layouts` is the only surface for plugin layouts. The same layout
 contribution can be mounted inside an IdeA layout cell or opened in a detached OS
 window. Do not add a separate manifest contribution type for windows.
diff --git a/src/index.ts b/src/index.ts
index fb39ad6..3ae4698 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -6,6 +6,8 @@ export type {
   IdeAPluginLayoutContribution,
   IdeAPluginMcpServerContribution,
   IdeAPluginMenuItemContribution,
+  IdeAPluginSkillContribution,
+  IdeAPluginSkillKind,
   IdeAPluginTopLevelMenuContribution
 } from "./manifest.js";
 export {
diff --git a/src/manifest.ts b/src/manifest.ts
index 126aa30..d576ce5 100644
--- a/src/manifest.ts
+++ b/src/manifest.ts
@@ -14,6 +14,7 @@ export interface IdeAPluginManifest {
    */
   activationScope?: IdeAPluginActivationScope;
   contributes?: {
+    skills?: IdeAPluginSkillContribution[];
     menus?: IdeAPluginTopLevelMenuContribution[];
     menuItems?: IdeAPluginMenuItemContribution[];
     slashCommands?: IdeAPluginSlashCommandContribution[];
@@ -26,10 +27,24 @@ export type IdeAPluginCapability = "ui" | "mcp" | "tooling";
 
 export type IdeAPluginActivationScope = "app" | "project";
 
+export type IdeAPluginSkillKind = "workflow" | "reference";
+
 export interface IdeAPluginEngineConstraints {
   idea?: string;
 }
 
+export interface IdeAPluginSkillContribution {
+  id: string;
+  /** Agent-facing name shown in the injected skill catalogue and accepted by idea_skill_read. */
+  name: string;
+  /** Short affordance shown to agents before they load the skill body. */
+  description: string;
+  /** Defaults to "workflow". */
+  kind?: IdeAPluginSkillKind;
+  /** Package-relative Markdown file, usually skills/<name>/SKILL.md. */
+  path: string;
+}
+
 export interface IdeAPluginTopLevelMenuContribution {
   id: string;
   label: string;
@@ -192,6 +207,20 @@ function validateContributes(value: unknown, errors: string[]): void {
     return;
   }
 
+  validateArray(value, "skills", errors, (skill, index) => {
+    requireString(skill, "id", errors, `contributes.skills[${index}].id`);
+    requireString(skill, "name", errors, `contributes.skills[${index}].name`);
+    requireString(skill, "description", errors, `contributes.skills[${index}].description`);
+    requireString(skill, "path", errors, `contributes.skills[${index}].path`);
+    if (typeof skill.kind === "string" && skill.kind !== "workflow" && skill.kind !== "reference") {
+      errors.push(`contributes.skills[${index}].kind must be "workflow" or "reference" when provided`);
+    } else if (skill.kind !== undefined && typeof skill.kind !== "string") {
+      errors.push(`contributes.skills[${index}].kind must be a string when provided`);
+    }
+    if (typeof skill.path === "string" && !skill.path.endsWith(".md")) {
+      errors.push(`contributes.skills[${index}].path must point to a .md file`);
+    }
+  });
   validateArray(value, "menus", errors, (menu, index) => {
     requireString(menu, "id", errors, `contributes.menus[${index}].id`);
     requireString(menu, "label", errors, `contributes.menus[${index}].label`);