Feature Request: Add HTTP Streamable transport support for remote MCP servers

Summary

The current type: "remote" MCP configuration only supports SSE (Server-Sent Events) transport. However, the MCP protocol now includes HTTP Streamable transport (also called http or streamable-http), which is used by several major MCP servers including Sanity.

Problem

When configuring Sanity's hosted MCP server:

{
  "mcp": {
    "sanity": {
      "type": "remote",
      "url": "https://mcp.sanity.io",
      "oauth": {}
    }
  }
}

OpenCode fails with:

SSE error: Non-200 status code (405)

This is because Sanity uses HTTP Streamable transport, not SSE. The 405 "Method Not Allowed" occurs because OpenCode sends a GET request expecting SSE, but Sanity expects POST requests for HTTP streaming.

Current Workaround

Using mcp-remote as a local proxy:

{
  "mcp": {
    "sanity": {
      "type": "local",
      "command": ["npx", "-y", "mcp-remote", "https://mcp.sanity.io", "--transport", "http-only"],
      "timeout": 60000
    }
  }
}

This works but adds unnecessary overhead and complexity.

Proposed Solution

Add native support for HTTP Streamable transport in remote MCP configuration:

{
  "mcp": {
    "sanity": {
      "type": "remote",
      "transport": "http",  // or "streamable-http"
      "url": "https://mcp.sanity.io",
      "oauth": {}
    }
  }
}

Or alternatively, a new type:

{
  "mcp": {
    "sanity": {
      "type": "http",  // new type alongside "remote" (SSE) and "local"
      "url": "https://mcp.sanity.io",
      "oauth": {}
    }
  }
}

Reference

Other MCP clients already support this:

Claude Code: claude mcp add -t http sanity https://mcp.sanity.io
Cursor: { "type": "http", "url": "https://mcp.sanity.io" }
VS Code: { "type": "http", "url": "https://mcp.sanity.io" }

See: https://www.sanity.io/docs/compute-and-ai/mcp-server

Environment

OpenCode version: 1.1.14
macOS version: 15.7.4
Affected MCP server: Sanity (https://mcp.sanity.io)

This issue might be a duplicate of existing issues. Please check:

Remote MCP should negotiate HTTP/Streamable before deprecated SSE #6242: Remote MCP should negotiate HTTP/Streamable before deprecated SSE
[FEATURE]: Support MCP servers that require POST-based or non-standard SSE handshake #5371: [FEATURE]: Support MCP servers that require POST-based or non-standard SSE handshake
HTTP 405 on Figma MCP #5636: HTTP 405 on Figma MCP (similar error with Figma MCP server)

Feel free to ignore if none of these address your specific case.

I tried your workaround with Figma, like this:

    "Figma": {
      "type": "local",
      "command": [
        "npx",
        "-y",
        "mcp-remote",
        "https://mcp.figma.com/mcp",
        "--transport",
        "http-only"
      ],
      "timeout": 60000
    }

But got the following error: Figma MCP error -32000: Connection closed

@gusvianadev I see the issue! You're using the workaround approach, but looking at my working config, the Figma MCP actually works directly as a remote server with OAuth. Here's an alternative you might want to try:

{
  "figma": {
    "type": "remote",
    "url": "https://mcp.figma.com/mcp",
    "timeout": 60000,
    "oauth": {}
  }
}

You don't actually need to do the MCP remote workaround for Figma. It supports remote type directly with OAuth authentication. It's probably because mcp-remote is trying to proxy a connection that Figma expects to handle directly through the OAuth flow.

Just remove the workaround config and use the direct remote connection. OpenCode will take care of the OAuth flow for you when you first connect.

If you also want the Figma Desktop integration (for local files), you can add this separately:

{
  "figma-desktop": {
    "type": "remote",
    "url": "http://127.0.0.1:3845/mcp",
    "timeout": 30000
  }
}

But start with the main Figma remote config. Then you can decide whether you want to use Figma Desktop as well.

I tried that but I get a 405 error, and I'm on Linux so I can't use the Figma Desktop app

@gusvianadev, I guess that the 405 error you're encountering on Linux is due to Figma MCP requiring a streamable HTTP transport and a personal access token instead of OAuth. Here’s the new configuration you could try:

{
  "figma": {
    "type": "local",
    "command": "npx",
    "args": ["-y", "mcp-remote", "https://mcp.figma.com/mcp", "--transport", "streamable-http"],
    "timeout": 120000,
    "env": {
      "FIGMA_ACCESS_TOKEN": "your-figma-personal-access-token"
    }
  }
}

And to get the PAT, go to figma.com, check "Personal Access Tokens" under your account settings, and create a new one there.

Streamable HTTP (not HTTP-only) and token authentication should bypass the Linux OAuth issues.

we already support both actually rn it just infers the correct one by attempting to connect to sse and http streamable, if both fail i guess it is confusing cause u see the sse error instead of streamable http, we should adjust that

But yeah we already support this

@rekram1-node

@rekram1-node the problem I've been having is this one:

>  opencode mcp auth Figma

┌  MCP OAuth Authentication
│
■  Authentication failed
│
■  HTTP 403: Invalid OAuth error response: SyntaxError: JSON Parse error: Unexpected identifier "Forbidden". Raw body: Forbidden
│
└  Done

This is my config:

  "mcp": {
    "Figma": {
      "type": "remote",
      "enabled": true,
      "url": "https://mcp.figma.com/mcp"
    },
  }

Is that a problem with my config or is it a bug?

@gusvianadev that's separate and unrelated, figma Mcp requires them to whitelist us as a client, best thing u can do is go bug them to approve it, nothing we can do unless we impersonate a valid approved client

feat: opencode support — legacy HTTP+SSE transport + agent wiring

feat(team-settings): add OpenCode host to MCP install panel

Must the MCP server support SSE?

I get the following error (can connect and auth from Claude, VS Code Copilot)

Is this because the server has /sse turned entirely off?

test

fix(kit): дефолтный транспорт SSE — opencode remote MCP умеет только SSE

This does appear broken if the MCP remote doesn't support SSE.

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Feature Request: Add HTTP Streamable transport support for remote MCP servers #8058

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Feature Request: Add HTTP Streamable transport support for remote MCP servers #8058

Description

Summary

Problem

Current Workaround

Proposed Solution

Reference

Environment

Activity

github-actions commented on Jan 12, 2026

necropheus commented on Jan 13, 2026

chindris-mihai-alexandru commented on Jan 13, 2026

necropheus commented on Jan 13, 2026

chindris-mihai-alexandru commented on Jan 13, 2026

rekram1-node commented on Jan 13, 2026

necropheus commented on Jan 13, 2026

rekram1-node commented on Jan 13, 2026

CharlieDigital commented on Jul 2, 2026

limjonathan commented on Aug 6, 2026

computerquip-work commented on Aug 13, 2026

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