Claude Code on the web: cloud sessions don't load user-configured MCP servers (only first-party GitHub works)

[ellmanj]

Summary

In Claude Code on the web (Research Preview, cloud sessions), only the first-party GitHub MCP integration is available. There appears to be no working path for users to add additional MCP servers to a cloud session.

What I tried

1. Project-scoped .mcp.json committed at the repo root on the session's branch:

   {"mcpServers": {"sentry": {"type": "sse", "url": "https://mcp.sentry.dev/mcp"}}}

   Started a fresh cloud session on the branch. The file is present in the working tree but no mcp__sentry__* tools are registered. Only mcp__github__* tools are available.

   This contradicts the docs at https://code.claude.com/docs/en/claude-code-on-the-web, which state that repo .mcp.json servers are loaded as "part of the clone".

2. Account-level Connectors at https://claude.ai/customize/connectors. Connected the Sentry connector (15 read-only tools, OAuth completed successfully, shows as Connected). Started a fresh Claude Code web session afterward — Sentry tools still not present. Connectors appear to be a claude.ai chat feature only, not surfaced to Code-on-web sessions.

What I observed in the cloud session

The harness injects only the GitHub MCP via a session-scoped config at /tmp/mcp-config-cse_<session-id>.json pointing at https://api.anthropic.com/v2/ccr-sessions/.../github/mcp. There is no equivalent injection for any other server, regardless of how it's configured upstream.

Expected

Either (a) project .mcp.json should be honored in cloud sessions as documented, or (b) account-level Connectors from claude.ai/customize/connectors should sync to Code-on-web sessions, or (c) the docs should clearly state that user-configurable MCPs are not yet supported on Code-on-web.

Environment

• Claude Code on the web (Research Preview), cloud session
• Date: 2026-04-28

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] Claude Code Web interactive sessions lost all claude.ai MCP connectors ~April 23, 2026 while routines retain them #53489
2. [BUG] Slack-initiated Claude Code sessions missing account-level MCP connectors #49010
3. [BUG] Claude Desktop: Web session mode lacks MCP server access despite configuration #11146

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[0xbrainkid]

This is a capability-surface continuity failure.

If cloud sessions on Claude Code Web do not load user-configured MCP servers and only first-party GitHub survives, then the user’s declared tool environment is not carrying across surfaces. That breaks a core expectation: the agent should arrive with the same capability boundary the user configured, not a silently reduced one.

Why it matters:

• the visible session may look healthy while key tools are simply missing
• users can misdiagnose failures as model behavior when the actual problem is capability loss at session start
• cross-surface trust collapses if local/web/cloud sessions do not share the same operative tool world

I would want clarity on:

1. whether the MCP config is absent from cloud session bootstrap or present but filtered
2. whether only user-configured servers are dropped while first-party integrations are hardcoded through another path
3. whether the UI can make capability downgrades explicit instead of letting the session appear complete

In agent systems, missing tools are not just missing features. They change what the session is. Silent capability shrinkage makes the environment itself hard to trust.

[HauntGuy]

Confirming this is still happening as of 2026-05-23, with two refinements that may help narrow it:

It's specifically user-added connectors, not "only GitHub." In my Code-on-web cloud sessions the first-party/managed connectors all load fine — GitHub and Gmail and Google Calendar — while my user-added <claude.ai> connectors (Bright Data, Tavily) are the only ones filtered out. So the gate appears to be on user/custom <claude.ai> connectors, not all non-GitHub ones.

It's a regression, not a never-worked gap. The same persistent cloud session used a user connector (Bright Data) successfully on 2026-05-22 — recorded scrape_as_markdown calls with returned content — then on 2026-05-23 those same connectors stopped loading. No change to my connector config in between.

The documented auth precondition is met. Session is <Claude.ai> subscription OAuth (ANTHROPIC_API_KEY unset, OAuth token present; solo Max plan, no org). Per the docs, <claude.ai> connectors should load under subscription auth — but they don't.

Server-side signature in the session debug log:

[claudeai-mcp] inference token lacks user:mcp_servers scope — <claude.ai> org connectors disabled
[WARN] Filtering out tool_reference for unavailable tool: mcp__Bright_Data__scrape_as_markdown
[WARN] Filtering out tool_reference for unavailable tool: mcp__Tavily__tavily_search   (+ all Tavily tools)

The filter fires before any connection attempt — there's no HTTP error from the provider; the connector is simply never provisioned into the session.

Not fixed by: full sign-out/in, desktop app update, or switching surface (reproduces on both the Windows desktop app and the iPhone app). Meanwhile Claude Chat on the same account/subscription uses the same connectors normally at the same moment, so the service and account are healthy.

Happy to share the exact cloud session ID privately for log correlation.

[nthornton2010]

The same thing is happening to me. I am using the Atlassian MCP connector which works fine in a local session, but fails to properly authenticate in a cloud session.