fix: sanitize lone Unicode surrogates before sending to Claude API#1009
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vzaliva wants to merge 2 commits intoqwibitai:mainfrom
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fix: sanitize lone Unicode surrogates before sending to Claude API#1009vzaliva wants to merge 2 commits intoqwibitai:mainfrom
vzaliva wants to merge 2 commits intoqwibitai:mainfrom
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WhatsApp messages can contain emoji encoded as lone surrogate characters (invalid UTF-16 that is legal in JS strings but rejected by JSON). When the API request body is serialised, Anthropic returns: 400 "no low surrogate in string" Fix: call String.prototype.toWellFormed() in escapeXml(), which replaces any lone surrogate with U+FFFD before the content enters the prompt. Also bumps tsconfig lib to ES2024 so the method is recognised by tsc (Node 20+ supports it natively).
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Note for users hitting this error before applying the fix: If you've already received the Session files are stored in |
Andy-NanoClaw-AI
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Status: Needs Review
This was referenced Mar 13, 2026
The previous fix (escapeXml/toWellFormed) only covered incoming WhatsApp message text. Lone surrogates can also enter the session transcript via tool results (file reads, bash output, web fetches) and get replayed in subsequent API calls, triggering the same 400 error. Fix: intercept every outbound API request in the credential proxy and replace lone \uXXXX surrogate escapes with \uFFFD before forwarding. Valid surrogate pairs are preserved. This is the authoritative last line of defence regardless of surrogate source. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Type of Change
.claude/skills/Description
WhatsApp messages can contain emoji encoded as lone surrogate characters — invalid UTF-16 that is legal in JS strings but rejected when serialised to JSON.
When the API request body is built, Anthropic returns:
400 "no low surrogate in string"
Fix: call
String.prototype.toWellFormed()inescapeXml(), which replaces any lone surrogate withU+FFFDbefore the content enters the prompt. Alsobumps
tsconfig.jsonlibtoES2024so the method is recognised bytsc(Node 20+ supports it natively, no runtime dependency change).For Skills
(not applicable)