[BUG] claude.ai MCP connectors not injected into cloud sessions (legacy Slack-spawned); attach is flaky per session

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Successor to #61223, which was auto-closed as stale without a fix.

Environment: Pro/Max account; connectors (Notion, Slack, Gmail) enabled at account level and working in interactive sessions started at claude.ai/code.

Observed 2026-07-31 across multiple sessions spawned by the legacy "Claude Code in Slack" integration (@Claude mention in a channel; sessions run under my account against a private GitHub repository):

1. Notion connector: never injected. Sessions report an empty mcpServers list ("No Notion MCP server is configured in this worker environment").
2. Slack posting: flaky. Some sessions had a Slack posting capability (used after a permission prompt); a later session reported "no Slack posting tool is attached to this session".
3. Cloud environment configuration DOES reach these sessions (a marker environment variable set in the Default environment echoes correctly in-session), so the gap is connector injection specifically, not environment plumbing.

Impact: Slack-spawned sessions cannot reach Notion and cannot reliably post back to the thread. Workarounds in use: a scoped Notion integration token plus api.notion.com on a Custom allowlist, and a Slack incoming webhook, both as environment variables, which the docs advise against (environments have no secrets store).

Happy to provide session IDs privately.

What Should Happen?

Notion and Slack connectors should work from claude.ai/code

Error Messages/Logs

Steps to Reproduce

Enable the Notion connector; confirm it works at claude.ai/code; @Claude in Slack with any repo task; ask the session to list mcpServers.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.220

Platform

Anthropic API

Operating System

Other

Terminal/Shell

Other

Additional Information

Here's what's actually running, pulled from the environment:

Active Claude Code version: 2.1.220 — that's what claude --version reports, and it matches AI_AGENT=claude-code_2-1-220_agent. The live binary is /opt/claude-code/bin/claude.

One wrinkle worth flagging: there's a two-version split in this container.

The executing binary reports 2.1.220 (that's the one serving your query).
But the npm-installed package tree under /opt/node22/lib is @anthropic-ai/claude-code@2.1.42, and the CLAUDE_CODE_VERSION env var also says 2.1.42.
So /opt/node22/bin/claude symlinks to /opt/claude-code/bin/claude (2.1.220), while the npm tree resolvable on PATH is the older 2.1.42. The one answering you is 2.1.220; the 2.1.42 references are a stale package copy / env var in the image.

Other environment-runner identifiers, if useful: CLAUDE_CODE_ENVIRONMENT_RUNNER_VERSION=release-1186d93b9-ext.

Short answer: Claude Code web 2.1.220 (running on model claude-opus-4-8).