Add support for entrypoint and mounts configuration fields

[Copilot]

The MCP Gateway spec now requires support for entrypoint, entrypointArgs, and mounts fields for containerized MCP servers.

Changes

• Config schema: Added entrypoint (string) and mounts ([]string) fields to StdinServerConfig
• Mount validation: Format source:dest:mode where mode is ro or rw, with non-empty path validation
• Docker command generation: Apply --entrypoint flag and -v volume mounts in correct order
• Documentation: Updated README with field descriptions, validation rules, and examples

Example

{
  "mcpServers": {
    "custom-app": {
      "type": "stdio",
      "container": "myorg/custom-mcp:latest",
      "entrypoint": "/custom/entrypoint.sh",
      "entrypointArgs": ["--verbose", "--debug"],
      "mounts": [
        "/host/config:/app/config:ro",
        "/host/data:/app/data:rw"
      ],
      "env": {
        "API_KEY": "${CUSTOM_API_KEY}"
      }
    }
  }
}

Generates: docker run --rm -i --entrypoint /custom/entrypoint.sh -v /host/config:/app/config:ro -v /host/data:/app/data:rw -e API_KEY=... myorg/custom-mcp:latest --verbose --debug

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• go.googlesource.com
  • Triggering command: /update-job-proxy /update-job-proxy /cast.go m ux-amd64/pkg/tool/linux_amd64/vet rtcf�� /x86_64-linux-gnu/13/liblto_plugin.so rg/toolchain@v0.0.1-go1.25.0.linux-amd64/src/net-I 0.1-go1.25.0.linux-amd64/pkg/tool/linux_amd64/vet s-through=-lgcc transform.go s-through=-lc 0.1-go1.25.0.linux-amd64/pkg/tool/linux_amd64/vet o_.o�� 1.0.9/bool.go 1.0.9/bool_func.go 0.1-go1.25.0.linux-amd64/pkg/tool/linux_amd64/vet go1.25.0 ions =0 0.1-go1.25.0.linux-amd64/pkg/tool/linux_amd64/vet (dns block)
  • Triggering command: /update-job-proxy /update-job-proxy DROP /home/REDACTED/go/origin test -e igiCert_High_Assurance_EV_Root_CA.pem /home/REDACTED/go/-e /usr/bin/test -bool 87dd93a0 pkg/mod/golang.oblob test -e Root_CA_G4.pem pkg/mod/golang.org/toolchain@v0.0.1-go1.25.0.lin/var/run/docker/runtime-runc/moby (dns block)
• go.yaml.in
  • Triggering command: /update-job-proxy /update-job-proxy /cast.go m ux-amd64/pkg/tool/linux_amd64/vet rtcf�� /x86_64-linux-gnu/13/liblto_plugin.so rg/toolchain@v0.0.1-go1.25.0.linux-amd64/src/net-I 0.1-go1.25.0.linux-amd64/pkg/tool/linux_amd64/vet s-through=-lgcc transform.go s-through=-lc 0.1-go1.25.0.linux-amd64/pkg/tool/linux_amd64/vet o_.o�� 1.0.9/bool.go 1.0.9/bool_func.go 0.1-go1.25.0.linux-amd64/pkg/tool/linux_amd64/vet go1.25.0 ions =0 0.1-go1.25.0.linux-amd64/pkg/tool/linux_amd64/vet (dns block)
  • Triggering command: /update-job-proxy /update-job-proxy DROP /home/REDACTED/go/origin test -e igiCert_High_Assurance_EV_Root_CA.pem /home/REDACTED/go/-e /usr/bin/test -bool 87dd93a0 pkg/mod/golang.oblob test -e Root_CA_G4.pem pkg/mod/golang.org/toolchain@v0.0.1-go1.25.0.lin/var/run/docker/runtime-runc/moby (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>MCP Gateway spec has changed</issue_title>
<issue_description>The input config spec for the MCP Gateway has changed in the following ways.

MCP servers now have

• "entrypoint": "string",
• "entrypointArgs": ["string"],
• "mounts": ["source:dest:mode"]

The Gateway should support these configuration options and apply them to any containers that it launches. Documentation and tests must also be consistent with the new configuration schema.

https://github.com/githubnext/gh-aw/blob/main/docs/src/content/docs/reference/mcp-gateway.md</issue_description>

<agent_instructions>Please make sure that the all inputs are well validated and tested and that the documentation is consistent and correct.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes MCP Gateway spec has changed #77

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