Claude Code Web: Go 1.26 not available in container environment

Description

When using Claude Code Web with a Go project that has go 1.26 in its go.mod, Claude's container environment only has Go 1.24.7 available and cannot download the required version due to network restrictions.

Error Message

The project requires Go 1.26 but only 1.24.7 is available locally, and network is unavailable to download it. Let me try to temporarily override the go directive to run the code generator locally.

Expected Behavior

1. The container environment should have a recent Go version available (ideally Go 1.26+), or have the ability to download it when needed.
2. go.dev and dl.google.com/go should be added to the trusted network allowlist. Other Go domains (proxy.golang.org, sum.golang.org, pkg.go.dev) are already trusted, but go.dev (where official Go binaries are downloaded from) is not. This means users cannot install/upgrade Go in their setup scripts without switching to full network access.

Workaround

Create a custom cloud environment with full network access and a setup script that installs Go from go.dev:

#!/bin/bash
GOVERSION=$(curl -sSL 'https://go.dev/dl/?mode=json' | grep -o '"go[0-9.]*"' | head -1 | tr -d '"')
curl -sSL "https://go.dev/dl/${GOVERSION}.linux-amd64.tar.gz" -o /tmp/go.tar.gz
sudo rm -rf /usr/local/go
sudo tar -C /usr/local -xzf /tmp/go.tar.gz

This does not work with "Trusted" network access — go.dev returns 403.

Steps to Reproduce

1. Open a Go project with go 1.26 in go.mod in Claude Code Web
2. Attempt any operation that requires building/running Go code
3. Observe the version mismatch error

Environment

• Product: Claude Code Web
• Go version in container: 1.24.7
• Go version required: 1.26