MCP server connection issues
Model Context Protocol servers that fail to start, connect, or stay connected.
10107 related issues · 1236 open · 8871 resolved · peaked at 1453 open (2026-08)
Backlog trend over time
The line shows how many issues in this topic were open at the end of each month, derived by
counting each issue from its creation date until it was closed. First-party data from the
anthropics/claude-code tracker.
All mcp server connection issues issues
Ranked by community engagement (reactions and comments).
- [FEATURE] Add the ability to manage multiple Claude accounts within the Claude Desktop app with easy switching between profiles.
- Support for AGENTS.md and .agents/skills/, the community has been asking since August 2025
- Feature Request: Add support for Agent Client Protocol (ACP)
- Allow MCP tools to be available only to subagent
- [FEATURE] MCP Tool Filtering: Allow Selective Enable/Disable of Individual Tools from Servers
- [FEATURE] Secure secrets injection for Claude Code on the web
- [Feature Request] Support for MCP Sampling to leverage Claude Max subscriptions and reduce API costs
- Implement Agent-Scoped MCP Configuration with Strict Isolation
- Support Tool Search and Programmatic Tool Use betas for reduced token consumption
- [Feature Request]: Add support for MCP Elicitation
- Enable Remote Control for Claude Code sessions in Claude Desktop App
- [FEATURE] VSCode Extension: Display context usage percentage in UI
- Claude Code cannot connect to GitHub's remote MCP server using OAuth authentication
- [Feature Request] Enable quick-toggle for MCP servers
- [FEATURE] Allow users to configure which shell the Bash tool uses or inherit initial shell
- Claude.ai MCP servers auto-injected into Claude Code without opt-in — causes OOM crashes on resource-constrained systems
- Support for other IDEs (Neovim/Emacs)
- Feature request: Support multiple Slack workspaces in the built-in Slack connector
- Feature Request: Microsoft 365 Connector for Max Plan Individual Users
- Feature Request: Lazy Loading for MCP Servers and Tools (95% context reduction possible)
- Capture MCP Tools Changed notifications - notifications/prompts/list_changed notifications
- [FEATURE] Add Scala (Metals) to the native LSP plugin lineup
- Support multiple Gmail accounts in MCP integration
- Feature: Per-agent MCP tool filtering to improve agent focus and accuracy
- [BUG] Claude Desktop doesn't connect to Custom MCPs altogether (not with OAuth 2.1 nor with SSE)
- Claude in Chrome extension not connecting despite being installed and enabled
- [FEATURE] Support Claude in Chrome for WSL environments
- Missing Token Refresh Mechanism for MCP Server Integrations
- [BUG] [BUG] Claude Desktop MCP tools failing with "Required" parameter error
- [FEATURE] Settings.json parent directory traversal for monorepos
- [BUG] SDK doesn't read from .mcp.json until the CLI is ran in the current working directory
- [FEATURE] Native Bitbucket Integration for Claude Code
- [BUG] claude.ai visualize feature broken — claudemcpcontent.com unreachable (DNS_PROBE_FINISHED_NXDOMAIN) --- PLEASE REVIEW!
- [BUG] Error: Permission to use WebSearch has been auto-denied in dontAsk mode.
- [CRITICAL] MCP Parameter Serialization Bug in Both Claude Code and Claude Desktop
- Bug Report API Error: 400 `tool_use` ids were found without `tool_result` blocks immediately after...
- Allow hiding/removing unused cloud connectors (Gmail, Google Calendar, etc.)
- [BUG] Scheduled routines fail every MCP tool call with "MCP tool call requires approval" on custom connectors (regression ~2026-05-20)
- History accumulation in .claude.json causes performance issues and storage bloat
- [BUG] Slack plugin fails to authenticate - "does not support dynamic client registration"
- [BUG] Cowork: "Failed to start Claude's workspace" — VM service not running, persists after reboot
- Claude Desktop: MCP servers fail with Protocol instance reuse error
- [BUG] Claude Desktop macOS requires quitting twice (Cmd+Q → wait → system Dock pop-up menu Quit)
- [BUG] Missing `scope` Parameter in Dynamic Client Registration and Authorization Requests
- [BUG] Claude Code does not work with MCP servers that does not implement Dynamic Client Registration
- [BUG] plugin:github:github MCP fails with HTTP 400 — malformed JSON-RPC payload missing version tag
- [BUG] Per-Turn Tool Call Limit Regression Breaks Agentic MCP/SSH Workflows in Claude Desktop
- [BUG] Fix ${CLAUDE_PLUGIN_ROOT} in command markdown OR support local project plugin installation
- [BUG] Cowork scheduled tasks ignore "Always allow" folder/tool permissions — prompts reappear every run (macOS)
- Feature Request: CLI Commands for MCP Server Enable/Disable (Hook Automation Support)
- MCP OAuth regression: client metadata document redirect_uris missing port causes auth failure for providers supporting CIMD
- [BUG] SDK doesn't read project level MCPs or Slash Commands for new queries
- Built-in Plan agent ignores parent settings.json permissions and repeatedly prompts for pre-approved tools
- [FEATURE] Support Azure DevOps repositories in Claude Code on the web (Cloud Sessions)
- [FEATURE] Claude can reconnect to a broken MCP in a manner similar to how it performs other actions
- Claude OAuth requires dynamic client registration, making Azure AD/Entra ID integration complex
- --channels plugin shows 'Channels are not currently available' but inbound notifications are ignored
- [BUG] Scheduled tasks cannot access MCP connectors until a user message warms the session
- [FEATURE REQUEST] Claude Code - Disable specific functions in MCP to save Context Tokens
- [FEATURE] Persistent user-level MCP configurations (enable/disable)
- Max Plan: Token usage increased ~3-5x without any configuration change (since ~March 28-29)
- [Bug] Jira Authentication Fails: Persistent Reconnection and Session Issues
- Claude Code freezes with 100% CPU during multi-agent task JSON serialization
- [BUG] Plan Mode can't be used with Bypass Permissions
- [BUG] [Error] Tool result could not be submitted.
- [FEATURE] Auto-approve WebSearch tool without prompts via permissions configuration
- [BUG] macOS: Claude Desktop never dispatches tools/call to the first-party Filesystem extension (tools/list succeeds, no tools/call in any log)
- [BUG] VS Code terminal steals focus even when running Claude Code externally with /ide (terminal not open)
- Multi-Session Support for Claude in Chrome (Tab Group Isolation)
- [BUG] MCP OAuth appends trailing slash to `resource` parameter, breaking Entra ID auth (AADSTS9010010)
- [BUG] Opus 4.7 mixes legacy XML tool-use format into JSON tool calls on longer payloads
- MCP servers in .claude/.mcp.json not loading properly
- [FEATURE] Gmail MCP Connector: Add gmail_modify_labels tool for archiving, labeling, and inbox management
- No session/conversation identifier sent to MCP servers — cannot distinguish concurrent sessions
- Claude Desktop 1.1.4173 crashes on startup — no window renders, process visible in Task Manager
- [BUG] MCP OAuth: Claude doesn't auto-refresh access tokens, daily "Connection expired" despite valid refresh token
- [Feature Request] Support MCP servers with Client ID Metadata Documents (CIMD) OAuth authentication
- Task agent fails with 'tools: Tool names must be unique' when parent has many MCP tools
- [BUG] permissions from user settings.json is NOT applied at project level
- [BUG] Terminal Paste Corruption from Bracketed Paste Mode
- [BUG] Memory leak in long-running idle Claude Code sessions
- Telegram plugin: inbound MCP channel notifications not delivered to conversation
- High CPU usage (100%+) when Claude Code instances are idle - v2.1.12
- [BUG] OAuth redirect_uri uses localhost instead of 127.0.0.1, violating RFC 8252 Section 7.3
- Feature Request: Extend Environment Variable Expansion to `settings.json` files
- Support pre-configured OAuth client credentials without requiring Dynamic Client Registration
- [BUG] Windows MSIX: "Edit Config" opens wrong claude_desktop_config.json — MCP servers silently fail to load
- Agent Teams: support per-teammate working directory, CLAUDE.md, and MCP configs
- Add dynamic loading/unloading of MCP servers during active sessions
- [BUG] Routines: MCP connector tool calls fail with "requires approval" despite connectors being added to routine
- Feature Request: Add support for Agent Client Protocol (ACP)
- [BUG] "MCP Tools Not Available in Conversation Interface Despite Successful Connection"
- [FEATURE] Gmail MCP Connector: Add file attachment support to gmail_create_draft and add gmail_send_draft tool
- [BUG] Cowork UI: Responses not rendering until user types; "working through complex response" hangs indefinitely
- [BUG] MCP OAuth tokens without expires_in and refresh_token silently expires
- Slack MCP plugin OAuth fails: redirect_uri not registered in Slack app configuration
- Feature: Declarative Tool Filtering in MCP Server Configuration
- [FEATURE] Open source Claude Code CLI
- Feature Request: Add /reload-mcps Command for MCP Server Management
- [BUG] Claude Code MCP client ignores scopes_supported from OAuth protected resource metadata, preventing refresh token issuance
- [BUG] 'env' vars from .claude/settings.json not passed to the plugins/mcps.
- [FEATURE] Multi-device Cowork: Allow concurrent Cowork agents on multiple machines under a single account
- Unified sessions, settings & projects across Desktop, Mobile and CLI
- Sandbox stubs break `git add .` and are indistinguishable from real repo state to the agent
- MCP claude.ai Microsoft 365 connector rejects personal Microsoft accounts (Hotmail/Outlook.com/Live)
- claude.ai Gmail MCP regression: create_draft missing threadId parameter
- [BUG] Claude cowork MCP Issue continues
- Subagents fail with 'prompt is too long' when user has many MCP servers (tool definitions exceed 200k)
- Critical: No way to bypass MCP tool approval prompts in VSCode extension
- [BUG] MCP servers not properly terminated when Claude Code exits, causing orphaned processes
- [BUG] Claude Code For VS Code does not use mcp servers at all
- [Feature Request] Selective MCP Access Control for SubAgents
- MCP servers declaring draft-07 outputSchema are entirely unusable: "unsupported dialect" rejected client-side before dispatch
- [BUG] Environment variables from `env` section not passed to MCP servers
- [BUG] .mcp.json is not read
- Grep and Glob tools missing entirely from registry under ENABLE_TOOL_SEARCH=true
- MCP servers, hooks, and plugins should auto-reload when config changes — no restart needed
- [BUG] Claude Desktop MCP fails on all parameterized calls for filesystem tool — "Cannot convert undefined or null to object"
- [Bug] Anthropic API Error: Image does not match provided media type
- [Bug] Fable 5 safeguard `[reasoning_extraction]` false-positives on a one-word greeting ("Hi")
- [BUG] Extreme token consumption — quota depleted in minutes with normal usage
- v2.1.27 hangs at 100% CPU after first response (v2.1.25 works)
- [BUG] env variable expansion not working in plugin .mcp.json
- [BUG] Cowork Google Drive MCP cannot see content in any Workspace Shared Drive
- Hard block on typing passwords breaks legitimate dev/test workflows - needs a permission-gated opt-in for own dev environments
- Critical: .claude.json bloat severely impacting user experience - consolidated community feedback
- [BUG] slack_read_channel / slack_read_thread drop message attachments and blocks
- Conversation history shows duplicate 'Warmup' titles and loads wrong conversations
- TUI relayouts (SIGWINCH / permission-mode toggle) spill entire transcript into scrollback as duplicate copies
- [FEATURE] Support `ref` and `path` parameters in plugin source schema
- [Feature Request] Claude should be able to reconnect/reset MCP server
- Support 1Password op:// secret references in settings.json env section
- Claude Desktop: MCP tool calls shown in UI but never sent to server
- Google Drive claude.ai connector not loading in VS Code extension despite being connected in claude.ai
- Notion plugin MCP server: persistent Internal Server Error after reinstall
- [BUG] Notion MCP connector serializes JSON object parameters as strings, breaking update/move/create operations
- Desktop app MCP Tools hanging for 5-10 minutes then failing.
- Feature Request: Runtime MCP Server Toggle
- BUG: MCP servers fail to connect in Claude Code despite correct configuration
- [BUG] Telegram MCP plugin: inbound notifications/claude/channel never delivered to session (outbound works)
- [BUG] Claude Code consistently degrades in performance over long sessions
- [BUG] Cannot connect Remote GitHub MCP Server
- Missing Tool Implementation: closeAllDiffTabs in MCP Protocol
- [BUG] Claude Code Chrome integration doesn't detect extension in Brave Browser
- CLI hangs at 99% CPU on startup with large session .jsonl files
- [FEATURE] Claude Code ↔ Cowork Bridge: Programmatically trigger Cowork tasks from Claude Code CLI
- [BUG] Claude-in-Chrome: Browser extension persistently fails to connect from CLI
- Skills consume full token count at startup instead of progressive disclosure (frontmatter only)
- [FEATURE] Support MCP server configuration in ~/.claude/settings.json (user-managed file)
- Feature request: shared context between Claude Code, Claude.ai and Cowork
- [BUG] Claude Desktop 1.1.3189 (Cowork) serializes MCP object parameters as strings, breaking Notion MCP writes
- [Bug] Claude in Chrome MCP bridge fails on Windows - socket discovery doesn't find named pipes
- [Feature Request] MCP Context Isolation - Assign MCPs to Forked Agent/Skill Contexts
- /sandbox creates empty stub files in project root when using git worktrees
- Claude Code freezes/hangs with no input accepted — 100% write ratio in terminal renderer
- [BUG] Claude Code SDK: SDK MCP server faills to connect due to closed stream
- [BUG] VS Code extension doesn't load Chrome browser tools in chat panel despite docs stating @browser should work (Linux)
- [BUG] Claude in Chrome MCP tools: "Navigation to this domain is not allowed" on all domains (v1.0.66)
- Feature Request: Remote Control support for VS Code chat mode
- Opus 4.6 comprehensive regression: loops, memory loss, ignored instructions - daily professional user report
- [BUG] Screenshot and JavaScript tools fail with "Cannot access a chrome-extension:// URL of different extension"
- [BUG] Claude Code - Persistent Logout & Configuration Loss Bug Report
- Google Drive MCP connector not passed through to Claude Code
- [BUG] Cloud scheduled tasks cannot access MCP connectors — tools not loaded into session
- [BUG] Excessive token consumption since 2.1.88 — 66% usage in 2 questions (Max 5x, Opus 4.6)
- Feature Request: Add YOLO mode (bypassPermissions) to Shift+Tab permission mode cycle
- [Bug] Anthropic API Error: Image media type mismatch with base64 data
- [FEATURE] GitHub MCP Connector for claude.ai web (OAuth-based PR Reviews)
- [BUG] OAuth Authentication Succeeds but MCP Reconnection Fails - Requires Restart
- [BUG] WebFetch "Unable to verify domain is safe" error
- [BUG] Remote Control (mobile): session silently hangs mid-execution; only local Esc recovers it — no remote unstick mechanism
- [Feature Request] Linux support for Claude Desktop App, Dispatch, and CoWork
- [BUG] Custom plugin subagents cannot access MCP tools (built-in agents can)
- [Bug] The .claude.json elephant in the room: Is this "vibe coding" in production?
- [Regression, Windows+macOS] Cross-session messaging silently broken since CCD 2.1.224+ — messages dropped, recipient sessions wedged 15-20 min (hadFirstResponse=false); fixed in 2.1.237 for some installs, stable channel still affected
- [BUG] Opus 4.8 repeatedly emits malformed tool_use blocks, entire response discarded (4.7 works fine)
- [BUG] --channels mode stops processing incoming messages after first response
- Telegram plugin: inbound messages not delivered to session
- [BUG] Claude Code MCP Server OAuth authentication doesn't work in SSH remote sessions
- [BUG] Bug Report - Claude Code 2.1.27 hangs on startup
- [Bug] /compact and auto-compact fail with 'Tool names must be unique' when MCP servers are configured
- [BUG] Agents Don't Inherit MCP Tool Access Despite Connected MCP Servers
- [BUG] MCP FastMCP Pydantic model parameters serialized as JSON strings causing validation errors
- Claude Code Desktop should honor managed-settings.json for all permissions
- Selective MCP Tool Activation for Project-Specific Contexts
- [BUG] Claude Desktop MCP: tool call responses dropped by client after first successful round-trip (Windows, regression in CCD v2.1.22)
- [BUG] API Error 400: MCP tool names exceeding 64 character limit
- [FEATURE] Microsoft 365 MCP:Add support for reading email attachments
- [BUG] Claude code does not obey values of MCP_TIMEOUT longer than 60 seconds
- [BUG] VSCode Extension missing MCP IDE Diagnostics tool and /bug command
- [BUG] MCP file system not working
- Massive Issues Today
- [BUG] Cowork — GitHub connector unusable: OAuth DCR unsupported, UI shows misleading state, Disconnect button dead
- [BUG] [regression] MCP tool results invisible in 2.1.88 — outputSchema safeParse guard returns null on schema mismatch
- Scheduled tasks cannot access HTTP MCP servers — missing user:mcp_servers scope
- context_window.used_percentage doesn't match internal context warning calculation
- [BUG] Claude Desktop 1.0.734: MCP servers fail to initialize - 'Cannot read properties of undefined (reading cmd)'
- [BUG] Claude Desktop: Web session mode lacks MCP server access despite configuration
- [ENHANCEMENT] [FOLLOW-UP] MCP notifications/message Support - Claude Code Receives But Doesn't Display Messages
- MCP Configuration Unexpectedly Deleted From File During Auto-Update