`docker mcp tools ls --gateway-arg ...` fails with `starting client: calling "initialize": EOF` in multi-server setup

[andreish]

What happened

In a multi-server setup (atlassian + gitlab + database-server), docker mcp tools ls with multiple --gateway-arg values fails with:

starting client: calling "initialize": EOF

But:

• each server works individually with its own tools ls --gateway-arg ...
• docker mcp gateway run with the same configs/secrets starts and lists tools successfully.

Environment

• OS: Fedora Linux
• Docker CLI: 29.2.1
• Docker MCP: v0.40.2-dev
• Servers: atlassian, gitlab, database-server

Repro (fails)

docker mcp tools ls \
  --gateway-arg=--servers=atlassian,gitlab,database-server \
  --gateway-arg=--additional-config=/home/<user>/.docker/mcp/atlassian.config.yaml \
  --gateway-arg=--additional-config=/home/<user>/.docker/mcp/gitlab.config.yaml \
  --gateway-arg=--additional-config=/home/<user>/.docker/mcp/database-server.config.yaml \
  --gateway-arg=--secrets=/home/<user>/.docker/mcp/secrets.atlassian.env:/home/<user>/.docker/mcp/secrets.gitlab.env
Output:
starting client: calling "initialize": EOF

Repro (works)
Single-server checks work:

atlassian only
gitlab only
database-server only
Also this works:

bash

docker mcp gateway run \
  --servers atlassian,gitlab,database-server \
  --additional-config ...atlassian.config.yaml \
  --additional-config ...gitlab.config.yaml \
  --additional-config ...database-server.config.yaml \
  --secrets ...secrets.stack.env \
  --transport sse --port 8814
It starts and lists all tools successfully.

Expected behavior
docker mcp tools ls --gateway-arg ... should work for multi-server/multi-config/multi-secret setups the same way gateway run does.