fixes to mention the app for customizatons (#61606)

Author: saritai

content/copilot/concepts/agents/about-agent-skills.md

@@ -12,7 +12,7 @@ contentType: concepts
 ---
 
 > [!NOTE]
-> Agent skills work with {% data variables.copilot.copilot_cloud_agent %}, {% data variables.copilot.copilot_code-review_short %}, the {% data variables.copilot.copilot_cli %}, and agent mode in {% data variables.product.prodname_vscode %}.
+> Agent skills work with {% data variables.copilot.copilot_cloud_agent %}, {% data variables.copilot.copilot_code-review_short %}, the {% data variables.copilot.copilot_cli %}, the {% data variables.copilot.github_copilot_app %}, and agent mode in {% data variables.product.prodname_vscode %}.
 
 ## About agent skills
 
@@ -35,4 +35,5 @@ To create or add agent skills, see:
 
 * [AUTOTITLE](/copilot/how-tos/use-copilot-agents/cloud-agent/add-skills)
 * [AUTOTITLE](/copilot/how-tos/copilot-cli/customize-copilot/add-skills)
+* [AUTOTITLE](/copilot/how-tos/github-copilot-app/customize-github-copilot-app)
 * [AUTOTITLE](/copilot/reference/customization-cheat-sheet)

content/copilot/concepts/agents/github-copilot-app.md

@@ -44,7 +44,7 @@ The {% data variables.copilot.github_copilot_app %} supports the following opera
 * **Parallel workspaces:** Run multiple isolated agent sessions simultaneously, each with a dedicated git worktree and branch. You can also run sessions in cloud sandboxes (public preview) hosted by {% data variables.product.github %}. For more information, see [AUTOTITLE](/copilot/concepts/about-cloud-and-local-sandboxes).
 * **Session modes:** Choose how you work with agents: Interactive (collaborative), Plan (agent plans, you approve), or Autopilot (fully autonomous). You can also select from multiple LLMs and adjust reasoning effort for each session.
 * **{% data variables.product.github %} integration:** Browse and find issues, start sessions from them, create and close pull requests, review pull requests, view CI check results, and search across your repositories—all within the app.
-* **Customizations:** Configure MCP servers, skills, extensions, and plugins globally or for each session.
+* **Customizations:** Configure and use global instructions, MCP servers, and agent skills.
 * **Automations:** Save recurring agent tasks and run them on a schedule or on demand.
 * **Quick chats:** Brainstorm in a conversation mode without creating a dedicated branch or workspace.
 * **Session history:** Use `/chronicle` to get insights from previous sessions, including work you started in the app.

content/copilot/concepts/context/mcp.md

@@ -36,7 +36,7 @@ category:
 
 The Model Context Protocol (MCP) is an open standard that defines how applications share context with large language models (LLMs). MCP provides a standardized way to connect AI models to different data sources and tools, enabling them to work together more effectively.
 
-You can use MCP to extend the capabilities of {% data variables.product.prodname_copilot %} by integrating it with a wide range of existing tools and services. MCP works across all major {% data variables.product.prodname_copilot_short %} surfaces—whether you're working in an IDE, using {% data variables.copilot.copilot_cli %}, or delegating tasks to an agent on {% data variables.product.prodname_dotcom_the_website %}. You can also use MCP to create new tools and services that work with {% data variables.product.prodname_copilot_short %}, allowing you to customize and enhance your experience.
+You can use MCP to extend the capabilities of {% data variables.product.prodname_copilot %} by integrating it with a wide range of existing tools and services. MCP works across all major {% data variables.product.prodname_copilot_short %} surfaces—whether you're working in an IDE, using {% data variables.copilot.copilot_cli %}, working in the {% data variables.copilot.github_copilot_app %}, or delegating tasks to an agent on {% data variables.product.prodname_dotcom_the_website %}. You can also use MCP to create new tools and services that work with {% data variables.product.prodname_copilot_short %}, allowing you to customize and enhance your experience.
 
 For more information on MCP, see [the official MCP documentation](https://modelcontextprotocol.io/introduction). For a curated list of MCP servers from partners and the community, see the [{% data variables.product.github %} MCP Registry](https://github.com/mcp).
 
@@ -45,7 +45,7 @@ To learn how to configure and use MCP servers, see:
 * [AUTOTITLE](/copilot/how-tos/provide-context/use-mcp/extend-copilot-chat-with-mcp) for {% data variables.copilot.copilot_chat_short %} in your IDE
 * [AUTOTITLE](/copilot/how-tos/copilot-cli/customize-copilot/add-mcp-servers) for {% data variables.copilot.copilot_cli_short %}
 * [AUTOTITLE](/copilot/how-tos/copilot-on-github/customize-copilot/configure-mcp-servers) for repository MCP configuration on {% data variables.product.prodname_dotcom_the_website %}
-
+* [AUTOTITLE](/copilot/how-tos/github-copilot-app/customize-github-copilot-app) for information on MCP server support in the {% data variables.copilot.github_copilot_app %}
 {% data reusables.copilot.mcp.mcp-policy %}
 
 ## Availability
@@ -54,6 +54,7 @@ MCP is supported across the following clients:
 
 * **IDEs**: There is broad support for local MCP servers in clients such as {% data variables.product.prodname_vscode %}, JetBrains IDEs, Xcode, and others. Support for remote MCP servers is growing, with editors like {% data variables.product.prodname_vscode %}, {% data variables.product.prodname_vs %}, JetBrains IDEs, Xcode, Eclipse, Cursor, and Windsurf providing this functionality with OAuth or PAT. To find out if your preferred editor supports remote MCP servers, check the documentation for your specific editor.
 * **{% data variables.copilot.copilot_cli_short %}**: {% data variables.copilot.copilot_cli %} supports both local and remote MCP servers. The {% data variables.product.github %} MCP server is built in and available without additional configuration.
+* **{% data variables.copilot.github_copilot_app %}**: The {% data variables.copilot.github_copilot_app %} (in {% data variables.release-phases.technical_preview %}) supports MCP servers configured in your repository or {% data variables.copilot.copilot_cli_short %} and lets you add additional MCP servers in app settings.
 * **{% data variables.copilot.copilot_cloud_agent %} and {% data variables.copilot.copilot_code-review_short %}**: {% data variables.product.prodname_dotcom_the_website %} supports MCP servers configured at the repository level. The configuration applies to both {% data variables.copilot.copilot_cloud_agent %} and {% data variables.copilot.copilot_code-review_short %}. The {% data variables.product.github %} MCP server and Playwright MCP server are configured by default.
 
 ## About the {% data variables.product.github %} MCP server

content/copilot/how-tos/copilot-on-github/customize-copilot/customize-cloud-agent/add-skills.md

@@ -16,7 +16,7 @@ redirect_from:
 ---
 
 > [!NOTE]
-> Agent skills work with {% data variables.copilot.copilot_cloud_agent %}, {% data variables.copilot.copilot_code-review_short %}, the {% data variables.copilot.copilot_cli %}, and agent mode in {% data variables.product.prodname_vscode %}.
+> Agent skills work with {% data variables.copilot.copilot_cloud_agent %}, {% data variables.copilot.copilot_code-review_short %}, the {% data variables.copilot.copilot_cli %}, the {% data variables.copilot.github_copilot_app %}, and agent mode in {% data variables.product.prodname_vscode %}.
 
 Agent skills are folders of instructions, scripts, and resources that {% data variables.product.prodname_copilot_short %} can load when relevant to improve its performance in specialized tasks. For more information, see [AUTOTITLE](/copilot/concepts/agents/about-agent-skills).