feat: add per-session MCP server support for REST API (parity with ACP)

Problem

ACP (newSession()) supports mcpServers parameter for per-session MCP configuration, but REST API POST /session doesn't.

This creates inconsistency for integrations that need dynamic MCP configuration via REST.

Use Case

External platforms (like MCP orchestrators) need to:

Create sessions via REST API
Attach user-specific MCP servers to each session
Currently impossible without ACP

Proposed Solution

Add mcpServers parameter to POST /session endpoint, matching ACP behavior:

POST /session
{
  "title": "My Session",
  "mcpServers": {
    "user-mcp": {
      "type": "remote",
      "url": "https://user-specific-mcp.com/sse"
    }
  }
}

Implementation

I've already implemented this and opened a PR: #6884

Changes are minimal (~15 lines):

Add mcpServers to Session.create.schema
Call MCP.add() in createNext()

All existing tests pass.

Questions

Is this something the team would consider? Happy to adjust the implementation based on feedback.

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

[FEATURE]: MCP auth configuration for multi-tenant serve deployments #5784: [FEATURE]: MCP auth configuration for multi-tenant serve deployments - addresses per-session MCP configuration via REST API for multi-tenant deployments

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

so When will OpenCode add support for per-session MCP servers?

This is a important feature in production environment

@haoqixu

Does the acp-sdk support passing mcpServers in the session: ACP#Session Setup, NewSessionRequest

In the source code opencode-agent.ts, the newSession function has a defined mcpServers parameter:agent.ts-mcpServers @haoqixu

But during the actual chat conversation process, are the mcpServers defined in the session state not being used?

I test in this way

curl -X POST 'http://localhost:14096/session' \
-H 'x-opencode-directory: /tmp' \
-H 'Content-Type: application/json' \
-d '{
        "mcpServers": [
            {
                "type": "http",
                "name": "custom-mcp-server",
                "url": "http://xxx/mcp/sse",
                "headers": [
                    {
                        "name": "Authorization",
                        "value": "Bearer wMU+xxx="
                    },
                    {
                        "name": "Content-Type",
                        "value": "application/json"
                    }
                ]
            }
        ]
    }
    ' | jq

does opencode support for per-session MCP servers?

in opencoder server rest api
there is no mcpServers in Session.create.schema

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feat: add per-session MCP server support for REST API (parity with ACP) #7004

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feat: add per-session MCP server support for REST API (parity with ACP) #7004

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Implementation

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github-actions commented on Jan 5, 2026

geosmart commented on Mar 12, 2026

geosmart commented on Mar 12, 2026

geosmart commented on Mar 12, 2026

github-actions commented on May 12, 2026

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