The API layer issues on Windows
Issues the maintainers labelled both platform:windows and area:api.
400 issues · 32 open · 368 resolved (92%) · first seen Mar 2, 2025
Is this getting better or worse?
This class of problem is still growing. 97 new reports in the last 90 days vs 74 in the 90 before — +31%. The open backlog peaked at 90 in 2025-12 and sits at 32 today.
Derived by counting each matching issue from its creation date until it closed. First-party
computation over the anthropics/claude-code tracker — the trend is not published
anywhere upstream.
Which builds report this
197 of these reports name the Claude Code build they were running, spanning 65 releases. Heaviest reporters:
- Claude Code v2.1.114
- Claude Code v2.1.19
- Claude Code v2.1.29
- Claude Code v2.1.141
- Claude Code v2.1.76
- Claude Code v2.1.104
- Claude Code v2.1.56
- Claude Code v2.1.17
Report volume, not a defect count: an issue can mention a build without that build having caused the failure. Versions come from the version string in the bug-report template, matched against real published tags.
Do these get fixed?
Median time to close is 37 days across 368 closures. Of the 368 closures with a recorded reason, 24% were closed as completed and 279 as not-planned or duplicate. The most recent completed fix landed in 2026-06.
Workarounds reported by the community
47 of these issues post a workaround someone says worked. The highest-engagement ones:
- [Bug] VS Code extension: Tool use concurrency error after Jan 23-24 update
- ✅ WORKAROUND FOUND The fix: Install VS Code extension version 2.1.17 while keeping CLI at 2.1.19 Steps: 1. In VS Code, go to Extensions 2. Find "Claude Code for VS Code" 3. Click the dropdown arrow next to Uninstall → "I…
Found in the thread of #20571 · still open - [Bug] Anthropic API Error: Tool Use Concurrency Limitation
- I tried many workaround without success. In my case, it was a specific PDF file causing the issue. Once unreferenced, it works.
Found in the thread of #9002 · resolved - [BUG] API Error: Rate limit reached despite Claude Max subscription and only 16% usage
- …nType: null and rateLimitTier: null. API credits were added as a workaround — they were consumed instantly (within seconds), leaving the account in debt. After fresh login subscription is recognized (subscriptionType: "m…
Found in the description of #29579 · still open - [BUG] Cowork Windows - Cannot connect to Claude API from workspace (Windows 11 Home)
- …same issue on Windows 11 Pro. Tried all of the recommended work-arounds and get the same result
Found in the thread of #24918 · resolved - [BUG] API Error: Server is temporarily limiting requests (not your usage limit) · Rate limited
- I have discovered a workaround - if you sign up for the GPT Codex Plan, you get a better coding agent and limits that are actually reflective of use. Solved my problem 100%.
Found in the thread of #53915 · still open
Excerpts are quoted from the linked issue so you can judge relevance before opening it. Threads that only ask for a workaround, or report that there is none, are excluded. These are community suggestions, not official guidance from Anthropic — read the full thread before applying one.
Matching issues 1–100
Ranked by community engagement (reactions weighted over comments). Listing the top 300 of 400 matches; the statistics above cover all 400.
- [Bug] VS Code extension: Tool use concurrency error after Jan 23-24 update
- [Bug] Anthropic API Error: Tool Use Concurrency Limitation
- [BUG] API Error: Rate limit reached despite Claude Max subscription and only 16% usage
- [BUG] Cowork Windows - Cannot connect to Claude API from workspace (Windows 11 Home)
- [BUG] Hitting much faster usage limits than before
- [BUG] API Error: Server is temporarily limiting requests (not your usage limit) · Rate limited
- [BUG] API 400
- [BUG] API Error (Connection error.)
- [BUG] Claude.ai completely down. Cannot access Claude code or website: Rate exceeded
- [BUG] API Error: Rate limit reached
- API Error: 401 {"type":"error","error":{"type":"authenticati...
- [BUG] Unsupported content type: redacted_thinking，Errors often occur when using the plugin.
- [BUG] Weekly Usage Limits Making Claude Subscriptions Unusable - This IS a bug.
- [Bug] Anthropic API Error: Image media type mismatch with base64 data
- Bug: API Error 400 - tool use concurrency issues
- Anthropic API Overloaded Errors Causing Retry Attempts on Windows
- [BUG] 529 error, overloaded.
- [BUG] Sonnet model consuming both "All models" AND "Somente Sonnet" limits
- [BUG] API Error: 500
- [BUG] /usage command fails with rate_limit_error when checking usage data
- API Error: 500 {"type":"error","error":{"type":"api_error","...
- API Error: 500
- Auto-compact fails with Opus 4.5 extended thinking blocks
- [BUG] API Error: 400 due to tool use concurrency issues. Run /rewind to recover the conversation.
- [BUG] API Error 400 - The request body is not valid JSON: str is not valid UTF-8: surrogates not allowed - mid-conversation error
- [Bug] Anthropic API Error: PNG screenshots sent with incorrect image/jpeg MIME type
- [BUG] Claude is Extremily Slow
- Bug Report: Path Patterns in allowedTools Not Honored in Non-Interactive Mode
- [Bug] Claude Code: Persistent Instruction Disregard and Output Quality Degradation
- [BUG] When context remaining is less than 10% (i.e. 70% usage), Claude Code stops working with an API timeout error.
- [BUG] Cowork Windows - CSP blocks a-api.anthropic.com, VM starts but API unreachable (Win 11 25H2)
- [BUG] Cowork VM boots successfully but API is unreachable on Windows
- Claude Code CLI Unusable: APIErrorterminated + Offline Flickering + Extreme Execution Delays
- [Bug] API Error 400 - Tool Use Concurrency Issues - Widespread Regression Affecting All Platforms
- [BUG] `ANTHROPIC_BASE_URL` ignored during setup
- [BUG] API Error: 400 `tool_use` ids were found without `tool_result` blocks immediately after: toolu_..... Each `tool_use` block must have a corresponding `tool_result` block in the next message.
- [BUG] Messages content type tool_reference not supported, causing API 400 in v2.1.69
- [BUG] claude limit reached in less than one hour on opus 4.1, windows, v2.0.1
- 400 error: empty text content block when background tasks complete during user input
- [BUG] Extremely slow thinking/response time on WSL2 - works fine on native Linux
- [Bug] Anthropic API Error: 500 Overloaded Request
- [Bug] Anthropic API Error: 500 Internal Server Error on all messages
- [Bug] Anthropic API Error: Server Overloaded (500)
- [BUG] Rate limit reached without any usage spent
- [Bug] Anthropic API Error: Internal Server Error (500)
- [BUG] Anthropic API Error: Overloaded
- [BUG] API Error: 500 {"type":"error","error":{"type":"api_error","message":"Internal server error"},"request_id"
- [BUG] [1M] "Long context beta is not yet available for this subscription" error on Max plan ($200/mo)
- [BUG] Persistent authentication error "Beim Senden des Anmeldelinks ist ein Fehler aufgetreten" on Windows login
- [BUG] Could not process image
- [Bug] Anthropic API Error: 500 Overloaded Request Failure
- [Bug] Anthropic API Error: Internal Server Error (500)
- [BUG] API Error: Rate Limit when using claude code (vscode) on max plan
- [Bug] Anthropic API Error: Cannot modify thinking blocks in multi-turn conversation
- [BUG] Intermittent mid-stream SSE stall — Opus 4.7/4.8, Sonnet 4.6, pause token emission 40–600s mid-response, latency increasing (VS Code extension)
- [BUG] 400 "cache_control cannot be set for empty text blocks" when pasting an image without a caption
- [BUG] Max 20x plan — Claude Code reports 100% usage while dashboard shows 73%, charged $53 in extra usage
- API Error: 400 due to tool use concurrency issues when reading multiple files
- [BUG] API Error 400 "tool use concurrency issues" on every tool call in VSCode extension
- [BUG] API Error: 400
- conversation compression
- [BUG] Opus limit reached shown even if Opus hasnt been used
- [Bug] Anthropic API Error: Tool Use IDs Without Tool Result Blocks When Parsing PDFs
- Anthropic API Connection Failures with Repeated Timeouts
- [Bug] Anthropic API Error: Internal Server Error (500)
- [BUG] Usage limit discrepancy: Claude Code blocked at 100% while claude.ai shows 73% on the same account
- [BUG] API Error 500 on all prompts including /feedback command - Sonnet 4.5 and Opus 4.5
- Claude AI terminal scroll issue | 1754510400
- [BUG] GitHub Integration Cannot Properly Read File Contents – Regression in Project Knowledge
- [BUG] OAuth tokens not passed to API - "has Authorization header: false
- API 500 Error Loop After Cumulative Context Exceeds Threshold
- [BUG] Server is temporarily limiting requests
- [BUG] False positive usage policy violation on computational biology research content
- API Error: thinking blocks in assistant message cannot be modified
- [BUG] API Error 400 'tool use concurrency issues' in VSCode extension on simple operations
- [Bug] Anthropic API Error: Internal Server Error (500)
- [BUG] Claude Code CLI - Rate limit error persisting after March 18-19 incident
- [BUG] Backend changes break MCP image analysis with GLM API - All Claude Code versions affected
- Claude Code: Session-Destroying Failures from Compaction Timeouts
- API Error: 500
- JSON.stringify produces lone surrogates in API request body (400 invalid high surrogate)
- API Error: thinking blocks cannot be modified during Write operations
- You've hit your limit · resets 11pm (America/Anchorage)
- [Bug] Persistent Edit Failures in Latest Claude Code Version
- Anthropic API Connection Timeout: Repeated Processing Errors
- [BUG] 2.1.154 appears to send messages[].role="system" to Anthropic-compatible providers, causing schema parse failures
- [BUG] Anthropic API Error: 500 Internal server error
- [Bug] Anthropic API Error: Invalid Credentials for Opus Model from Claude Code
- Invalid Model Name for Haiku Agent in Command Execution
- [BUG] 500 No available Claude accounts support the requested model: claude-sonnet-4-5
- [BUG] Opus weekly limit reached within 5 hours.
- [BUG] [BUG] API Error 400: "The content[].thinking in the thinking mode must be passed back to the API" - frequent interruptions during conversation
- [BUG] Bug: Rate limit errors on Pro Plan at 26% usage — rate limit stuck per-session, contradicts documentation
- [BUG] Mismatched content block type content_block_delta thinking
- [Bug] Anthropic API Error: HTTP 500 Internal Server Error
- [BUG] API Error: 403 {"error":{"type":"forbidden","message":"Request not allowed"}} · Please run /login
- [BUG] Claude Code hangs on in loading model when press /model
- [BUG] Stream stall + sdk_stream_ended_no_result after update to 2.1.141
- [BUG] API Error: 500 {"type":"error","error":{"type":"api_error","message":"Internal server error"},"request_id":"req_011Ca5kALiTNUQsFFqgm7dwc"} · check status.claude.com
- [BUG] CLAUDE CODE CLI: API Error: Rate limit reached