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Claude Code Issues / Error strings / SyntaxError: Unexpected token

SyntaxError: Unexpected token

A parse failed, most often on config or a truncated JSON response.

698 issues · 30 open · 668 resolved (96%) · first seen Feb 25, 2025

First response · local

What to do now

Most likely: The local Claude Code process crashed while parsing or executing.

  1. Record the Claude Code version and the first stack frame before restarting.
  2. Try a fresh session with the same minimal input to distinguish corrupted state from a repeatable crash.
  3. Preserve logs and compare reports from the same version before downgrading.

These are conservative triage steps, not an official Anthropic fix. Use the issue and workaround evidence below before making a destructive configuration change.

Is this getting better or worse?

This class of problem is converging. 43 new reports in the last 90 days vs 162 in the 90 before — -73%. The open backlog peaked at 129 in 2025-12 and sits at 30 today.

0 32 65 97 129 2025-022025-082026-022026-08
2025-02 — First reports2025-12 — Peak backlog (129 open)2026-04 — Most new reports (86)

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

301 of these reports name the Claude Code build they were running, spanning 102 releases. Heaviest reporters:

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 4 days across 668 closures. Of the 668 closures with a recorded reason, 19% were closed as completed and 541 as not-planned or duplicate. The most recent completed fix landed in 2026-08.

Workarounds reported by the community

69 of these issues post a workaround someone says worked. The highest-engagement ones:

API Error: 400 due to tool use concurrency issues. Run /rewind to recover the conversation. - [Bug] Anthropic API Error: Unexpected 400 Bad Request Response
…67 (my report) 8887 8893 8894 8895 8897 8903 EDIT (Oct 14): Workaround for tool use/tool result 400 errors: A research-backed solution was posted on Oct 10: Add the provided instructions to your global CLAUDE.md (~/.clau…
Found in the thread of #8763 · resolved
[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] Terminal Paste Corruption from Bracketed Paste Mode
…Copy/paste any text Expected vs Actual Expected : Actual : Workarounds - - - Restart terminal Technical Details Claude Code leaves terminal in corrupted bracketed paste mode. The / characters are escape sequences ( / )…
Found in the description of #3134 · resolved
[BUG] Cowork Edit/Write tools silently truncate files via byte-conservation buffer cap (deterministic, fires at all file sizes)
…ull correct content while the file on disk was corrupt. The workaround holds. Every reporter who moved all writes to bash reports zero further loss. No counterexamples in the thread. What is not settled: the mechanism Th…
Found in the description of #53940 · still open
[BUG] awsAuthRefresh is not working properly after upgrade to claude code 2.0
…ms to want that to be json, which it isn't. I've tried some work arounds, like "aws sso login --profile profile-name --output json" or "aws sso login --profile pofile-name 1 /dev/null". The first one does nothing, the se…
Found in the thread of #8447 · resolved

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 698 matches; the statistics above cover all 698.

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