---
title: "MCP legacy HTTP and SSE"
canonical: "https://canmyagentuse.com/features/mcp-legacy-sse"
contentKind: "feature"
locale: "en"
description: "Connect through the superseded HTTP plus SSE transport when migration compatibility is required. Compatibility evidence is tracked independently from other MCP capabilities."
llmSummary: "MCP legacy HTTP and SSE is an atomic MCP capability. Support for another MCP primitive does not imply this capability."
publishedAt: "2026-08-28T00:00:00.000Z"
updatedAt: "2026-08-28T00:00:00.000Z"
verifiedAt: "2026-08-28"
tags: ["interfaces","mcp"]
---

# MCP legacy HTTP and SSE

MCP legacy HTTP and SSE is an atomic MCP capability. Support for another MCP primitive does not imply this capability.

- HTML: https://canmyagentuse.com/features/mcp-legacy-sse
- JSON: https://canmyagentuse.com/api/v1/features/mcp-legacy-sse.json
- Markdown: https://canmyagentuse.com/features/mcp-legacy-sse.md

Terminology basis: **MCP 2026-07-28** — https://modelcontextprotocol.io/specification/2026-07-28.

## Current support at a glance

MCP legacy HTTP and SSE: 6 supported, 0 partial, 1 unsupported, 24 unreviewed across 31 cataloged products.

- Reviewed current products: 7 of 31
- Supported: 6
- Partial: 0
- Unsupported: 1
- Unreviewed: 24
- Not applicable: 0

Unknown or unreviewed means insufficient published evidence; it does not mean unsupported.

Connect through the superseded HTTP plus SSE transport when migration compatibility is required.

The Grok Bot cell is registry-listed for migration compatibility. New deployments should prefer the current transport where the server supports it.

## Catalog context

- Category: [interfaces](/categories/interfaces.md)
- Specification: [mcp](/specs/mcp.md) — revision 2026-07-28
- Aliases: MCP SSE
- Family: [Model Context Protocol](/features/mcp.md)
- Siblings: [MCP Apps](/features/mcp-apps.md), [MCP cancellation](/features/mcp-cancellation.md), [MCP client role](/features/mcp-client-role.md), [MCP elicitation](/features/mcp-elicitation.md), [MCP list-changed notifications](/features/mcp-list-changed.md), [MCP logging](/features/mcp-logging.md), [MCP OAuth authorization](/features/mcp-oauth.md), [MCP progress notifications](/features/mcp-progress.md), [MCP prompt-list notifications](/features/mcp-prompts-list-changed.md), [MCP prompts](/features/mcp-prompts.md), [MCP Registry metadata](/features/mcp-registry.md), [MCP resource subscriptions](/features/mcp-resource-subscriptions.md), [MCP resources](/features/mcp-resources.md), [MCP revision compatibility](/features/mcp-revision.md), [MCP roots](/features/mcp-roots.md), [MCP sampling](/features/mcp-sampling.md), [MCP server instructions](/features/mcp-server-instructions.md), [MCP server role](/features/mcp-server-role.md), [MCP stdio transport](/features/mcp-stdio.md), [MCP Streamable HTTP](/features/mcp-streamable-http.md), [MCP task listing](/features/mcp-task-listing.md), [MCP tasks](/features/mcp-tasks.md), [MCP tools](/features/mcp-tools.md)

## Compatibility assertions

Unknown means insufficient published evidence; it does not mean unsupported.

### ChatGPT (web)

- Harness: [ChatGPT](/harnesses/chatgpt-web.md)
- current: **Unknown**
- preview: **Unknown**

### Claude (web)

- Harness: [Claude](/harnesses/claude-web.md)
- current: **Unknown**
- preview: **Unknown**

### Gemini (web)

- Harness: [Gemini](/harnesses/gemini-web.md)
- current: **Unknown**
- preview: **Unknown**

### Copilot (web)

- Harness: [Copilot](/harnesses/copilot-web.md)
- current: **Unknown**
- preview: **Unknown**

### Grok (web)

- Harness: [Grok](/harnesses/grok-web.md)
- current: **Unknown**
- preview: **Unknown**

### Grok Bot (desktop)

- Harness: [Grok Bot](/harnesses/grok-bot-desktop.md)
- current: **Supported**
  - Target: hosted-observation — 2026-08-28 Agent Plugins compatible-client listing; observed 2026-08-28
  - Environment: hosted-default
  - Constraint (runtime): superseded transport support is registry-listed and was not independently tested by Can My Agent Use
  - Constraint (policy): organization server and network allowlists can block a remote server
  - Evidence: [Agent Plugins — Compatible clients](https://agent-plugins.org/compatible-clients) — listed; observed 2026-08-28
  - Qualification note 1: Evidence checked 2026-08-28: the Agent Plugins compatible-client registry explicitly lists legacy MCP SSE for Grok Bot. This is registry evidence, not an independent transport test.

### Perplexity (web)

- Harness: [Perplexity](/harnesses/perplexity-web.md)
- current: **Unknown**
- preview: **Unknown**

### Le Chat (web)

- Harness: [Le Chat](/harnesses/le-chat.md)
- current: **Unknown**
- preview: **Unknown**

### Devin (web)

- Harness: [Devin](/harnesses/devin-web.md)
- current: **Unknown**
- preview: **Unknown**

### Replit Agent (web)

- Harness: [Replit Agent](/harnesses/replit-agent.md)
- current: **Unknown**
- preview: **Unknown**

### ChatGPT (desktop)

- Harness: [ChatGPT](/harnesses/chatgpt-desktop.md)
- current: **Unknown**
- preview: **Unknown**

### Claude (desktop)

- Harness: [Claude](/harnesses/claude-desktop.md)
- current: **Unknown**
- preview: **Unknown**

### Cursor (desktop)

- Harness: [Cursor](/harnesses/cursor.md)
- current: **Supported**
  - Target: dated-documentation — current Cursor MCP documentation observed 2026-08-28; observed 2026-08-28
  - Environment: local-default
  - Constraint (transport): SSE remains supported for compatibility, while Cursor separately documents Streamable HTTP for current HTTP endpoints
  - Evidence: [Cursor — Model Context Protocol](https://prod.cursor.com/docs/mcp) — documented; observed 2026-08-28
  - Qualification note 4: Evidence checked 2026-08-28: Cursor documents SSE as a supported local or remote MCP transport and distinguishes it from Streamable HTTP.
- preview: **Unknown**

### OpenWork Desktop (desktop)

- Harness: [OpenWork Desktop](/harnesses/openwork-desktop.md)
- current: **Unknown**

### Copilot Chat (desktop)

- Harness: [Copilot Chat](/harnesses/vscode-copilot.md)
- current: **Unknown**
- preview: **Unknown**

### Chrome WebMCP origin trial (desktop)

- Harness: [Chrome WebMCP origin trial](/harnesses/chrome-webmcp-preview.md)
- current: **Unknown**

### Windsurf (desktop)

- Harness: [Windsurf](/harnesses/windsurf.md)
- current: **Unknown**
- preview: **Unknown**

### Zed Agent (desktop)

- Harness: [Zed Agent](/harnesses/zed-agent.md)
- current: **Unsupported**
  - Target: dated-documentation — Zed source commit e3adf43f37d7 observed 2026-08-28; observed 2026-08-28
  - Environment: local-default
  - Constraint (transport): SSE response bodies on Zed's POST-based Streamable HTTP path do not constitute the superseded dedicated HTTP-plus-SSE transport
  - Evidence: [Zed source — MCP transport module at e3adf43](https://github.com/zed-industries/zed/blob/e3adf43f37d7a2a9c165a78b255d293b0848d2d0/crates/context_server/src/transport.rs) — documented; observed 2026-08-28
  - Evidence: [Zed source — MCP HTTP transport at e3adf43](https://github.com/zed-industries/zed/blob/e3adf43f37d7a2a9c165a78b255d293b0848d2d0/crates/context_server/src/transport/http.rs) — documented; observed 2026-08-28
  - Qualification note 7: Evidence checked 2026-08-28: Zed's pinned transport module exposes only stdio and a single-endpoint POST-based HTTP transport; it does not implement the superseded HTTP-plus-SSE client transport.
- preview: **Unknown**

### Continue (desktop)

- Harness: [Continue](/harnesses/continue.md)
- current: **Supported**
  - Target: dated-documentation — Continue source commit 5522c6f44ca0 and current documentation observed 2026-08-28; observed 2026-08-28
  - Environment: local-default
  - Constraint (transport): SSE is an explicit legacy remote transport and remains separate from Continue's Streamable HTTP path
  - Evidence: [Continue — Model Context Protocol](https://docs.continue.dev/customize/deep-dives/mcp) — documented; observed 2026-08-28
  - Evidence: [Continue source — MCP desktop client at 5522c6f](https://github.com/continuedev/continue/blob/5522c6f44ca0ac3528b37244818fbfa39b5af470/core/context/mcp/MCPConnection.ts) — documented; observed 2026-08-28
  - Qualification note 6: Evidence checked 2026-08-28: Continue documents an explicit `sse` remote transport and its pinned desktop client constructs the MCP SDK SSE client transport.
- preview: **Unknown**

### Cline (desktop)

- Harness: [Cline](/harnesses/cline.md)
- current: **Supported**
  - Target: dated-documentation — current Cline MCP documentation observed 2026-08-28; observed 2026-08-28
  - Environment: local-default
  - Constraint (transport): SSE is retained for legacy compatibility; Cline recommends explicit Streamable HTTP for current remote servers
  - Evidence: [Cline — Model Context Protocol](https://docs.cline.bot/mcp/mcp-overview) — documented; observed 2026-08-28
  - Qualification note 5: Evidence checked 2026-08-28: Cline documents an explicit `sse` transport for legacy remote servers and retains SSE as the default when a remote transport type is omitted.
- preview: **Unknown**

### JetBrains AI (desktop)

- Harness: [JetBrains AI](/harnesses/jetbrains-ai.md)
- current: **Unknown**
- preview: **Unknown**

### Warp (desktop)

- Harness: [Warp](/harnesses/warp.md)
- current: **Unknown**
- preview: **Unknown**

### Claude CLI (cli)

- Harness: [Claude CLI](/harnesses/claude-cli.md)
- current: **Supported**
  - Target: dated-documentation — current Claude Code MCP documentation; observed 2026-08-28
  - Environment: local-default
  - Constraint (transport): SSE is retained for legacy compatibility; Anthropic recommends the HTTP transport where the server supports it
  - Evidence: [Anthropic — Connect Claude Code to tools via MCP](https://code.claude.com/docs/en/mcp) — documented; observed 2026-08-28
  - Qualification note 2: Evidence checked 2026-08-28: Anthropic documents the `sse` transport for legacy remote Claude Code MCP servers while recommending HTTP for current servers.
- preview: **Unknown**

### ChatGPT CLI (cli)

- Harness: [ChatGPT CLI](/harnesses/chatgpt-cli.md)
- current: **Unknown**
- preview: **Unknown**

### Codex CLI (cli)

- Harness: [Codex CLI](/harnesses/codex-cli.md)
- current: **Unknown**
- preview: **Unknown**

### OpenCode (cli)

- Harness: [OpenCode](/harnesses/opencode.md)
- current: **Unknown**
- preview: **Unknown**

### Gemini CLI (cli)

- Harness: [Gemini CLI](/harnesses/gemini-cli.md)
- current: **Supported**
  - Target: dated-documentation — Gemini CLI MCP documentation updated 2026-06-18; observed 2026-08-28
  - Environment: local-default
  - Constraint (transport): SSE endpoints can use headers or OAuth; new deployments should prefer Streamable HTTP where available
  - Evidence: [Google — MCP servers with Gemini CLI](https://geminicli.com/docs/tools/mcp-server/) — documented; observed 2026-08-28
  - Qualification note 3: Evidence checked 2026-08-28: Gemini CLI documents SSE endpoints as one of its three supported MCP transport types.
- preview: **Unknown**

### Aider (cli)

- Harness: [Aider](/harnesses/aider.md)
- current: **Unknown**
- preview: **Unknown**

### Goose (cli)

- Harness: [Goose](/harnesses/goose.md)
- current: **Unknown**
- preview: **Unknown**

### Copilot CLI (cli)

- Harness: [Copilot CLI](/harnesses/copilot-cli.md)
- current: **Unknown**
- preview: **Unknown**

### Amp (cli)

- Harness: [Amp](/harnesses/amp-cli.md)
- current: **Unknown**
- preview: **Unknown**