---
title: "Interfaces"
canonical: "https://canmyagentuse.com/categories/interfaces"
contentKind: "category"
locale: "en"
description: "Protocols and UI contracts between agents and hosts."
llmSummary: "Category Interfaces: Protocols and UI contracts between agents and hosts."
publishedAt: "2026-08-28T00:00:00.000Z"
updatedAt: "2026-08-28T00:00:00.000Z"
verifiedAt: null
tags: ["category"]
---

# Interfaces

Category Interfaces: Protocols and UI contracts between agents and hosts.

- HTML: https://canmyagentuse.com/categories/interfaces
- Markdown: https://canmyagentuse.com/categories/interfaces.md

Protocols and UI contracts between agents and hosts.

The index groups these capabilities by job rather than vendor.

## Capabilities

- [Agent Plugins failure isolation](/features/agent-plugin-failure-isolation.md) — Agent Plugins failure isolation is atomic and does not follow automatically from broader plugins support.
- [Agent Plugins packaged MCP](/features/agent-plugin-mcp.md) — Agent Plugins packaged MCP is atomic and does not follow automatically from broader plugins support.
- [Agent Plugins packaged skills](/features/agent-plugin-skills.md) — Agent Plugins packaged skills is atomic and does not follow automatically from broader plugins support.
- [Agent Plugins portable manifest](/features/agent-plugin-core.md) — Agent Plugins portable manifest is atomic and does not follow automatically from broader plugins support.
- [AGENTS.md root instructions](/features/agents-md.md) — AGENTS.md root instructions is atomic and does not follow automatically from broader instructions support.
- [Custom instructions](/features/custom-instructions.md) — Custom instructions persist user- or project-scoped guidance. Storage format, discovery, scope, and precedence are qualifiers.
- [MCP Apps](/features/mcp-apps.md) — MCP Apps let tools return interactive interfaces that render inside a compatible MCP host. Selected current-track cells are sourced; all others remain unknown.
- [MCP cancellation](/features/mcp-cancellation.md) — MCP cancellation is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP client role](/features/mcp-client-role.md) — MCP client role is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP elicitation](/features/mcp-elicitation.md) — MCP elicitation is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP legacy HTTP and SSE](/features/mcp-legacy-sse.md) — MCP legacy HTTP and SSE is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP list-changed notifications](/features/mcp-list-changed.md) — MCP list-changed notifications is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP logging](/features/mcp-logging.md) — MCP logging is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP OAuth authorization](/features/mcp-oauth.md) — MCP OAuth authorization is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP progress notifications](/features/mcp-progress.md) — MCP progress notifications is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP prompt-list notifications](/features/mcp-prompts-list-changed.md) — MCP prompt-list notifications is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP prompts](/features/mcp-prompts.md) — MCP prompts: Invoke reusable MCP prompt templates. Unreviewed harness cells remain unknown until dated public evidence exists.
- [MCP Registry metadata](/features/mcp-registry.md) — MCP Registry metadata is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP resource subscriptions](/features/mcp-resource-subscriptions.md) — MCP resource subscriptions is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP resources](/features/mcp-resources.md) — MCP resources: Read MCP resources as live context. Unreviewed harness cells remain unknown until dated public evidence exists.
- [MCP revision compatibility](/features/mcp-revision.md) — MCP revision compatibility is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP roots](/features/mcp-roots.md) — MCP roots is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP sampling](/features/mcp-sampling.md) — MCP sampling is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP server instructions](/features/mcp-server-instructions.md) — MCP server instructions is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP server role](/features/mcp-server-role.md) — MCP server role is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP stdio transport](/features/mcp-stdio.md) — MCP stdio transport is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP Streamable HTTP](/features/mcp-streamable-http.md) — MCP Streamable HTTP is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP task listing](/features/mcp-task-listing.md) — MCP task listing is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP tasks](/features/mcp-tasks.md) — MCP tasks is an atomic MCP capability. Support for another MCP primitive does not imply this capability.
- [MCP tools](/features/mcp-tools.md) — MCP tools let a harness invoke operations exposed by a Model Context Protocol server. Selected current-track cells are sourced; all others remain unknown.
- [Model Context Protocol](/features/mcp.md) — MCP is a capability family. Support is rolled up from atomic child capabilities so tool support never implies prompt, resource, or app support.
- [Native plugin system](/features/native-plugins.md) — A native plugin system is product-specific and does not establish support for the portable Agent Plugins manifest.
- [Nested AGENTS.md instructions](/features/nested-agents-md.md) — Nested AGENTS.md instructions is atomic and does not follow automatically from broader instructions support.
- [Persistent instructions](/features/instructions.md) — Persistent instructions are a capability family covering AGENTS.md, nested scopes, and native rule systems.
- [Plugin marketplace](/features/plugin-marketplace.md) — A plugin marketplace is a documented registry or marketplace for discovering and installing extensions. Update, removal, private-extension, and organization-policy behavior are qualifiers.
- [Plugin systems](/features/plugins.md) — Plugin support is a family of independent claims covering portable manifests, native extensions, packaged skills, packaged MCP, distribution, isolation, and vendor extensions.
- [Plugin vendor extensions](/features/plugin-vendor-extensions.md) — Plugin vendor extensions is atomic and does not follow automatically from broader plugins support.
- [Project rules](/features/native-rules.md) — Product-native rules is atomic and does not follow automatically from broader instructions support.
- [Streaming output](/features/streaming-output.md) — Streaming output displays text or tool events before a run completes. Event types, ordering, transport, and structured output are qualifiers.
- [Structured outputs](/features/structured-output.md) — Structured outputs are documented JSON or schema-constrained product outputs; unreviewed harness cells remain unknown.
- [WebMCP](/features/webmcp.md) — WebMCP is a draft capability family covering imperative and declarative tools, discovery and execution, permissions, cancellation, and security annotations.
- [WebMCP declarative form tools](/features/webmcp-declarative-tools.md) — WebMCP declarative form tools is an atomic WebMCP capability and does not imply every other part of the draft.
- [WebMCP execution cancellation](/features/webmcp-cancellation.md) — WebMCP execution cancellation is an atomic WebMCP capability and does not imply every other part of the draft.
- [WebMCP imperative tools](/features/webmcp-imperative-tools.md) — WebMCP imperative tools is an atomic WebMCP capability and does not imply every other part of the draft.
- [WebMCP permissions policy](/features/webmcp-permissions-policy.md) — WebMCP permissions policy is an atomic WebMCP capability and does not imply every other part of the draft.
- [WebMCP security annotations](/features/webmcp-security-annotations.md) — WebMCP security annotations is an atomic WebMCP capability and does not imply every other part of the draft.
- [WebMCP tool discovery](/features/webmcp-tool-discovery.md) — WebMCP tool discovery is an atomic WebMCP capability and does not imply every other part of the draft.
- [WebMCP tool execution](/features/webmcp-tool-execution.md) — WebMCP tool execution is an atomic WebMCP capability and does not imply every other part of the draft.