fix(js): don't treat <thinking> inside code blocks as thinking tags#235
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gadenbuie wants to merge 2 commits into
Open
fix(js): don't treat <thinking> inside code blocks as thinking tags#235gadenbuie wants to merge 2 commits into
gadenbuie wants to merge 2 commits into
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Track fenced code block state during streaming so that <thinking> tags encountered inside ``` or ~~~ blocks are emitted as plain content rather than parsed as thinking blocks. Also exclude inline backtick spans from thinking-tag detection in the non-streaming (splitThinkingBlocks) path. Previously, a chunk boundary where the prior chunk ended with a non-newline character (e.g. a backtick) and the next chunk began with <thinking> would incorrectly enter thinking mode because `before.trim() === ""` was the only guard — the newline-boundary check was missing.
cpsievert
approved these changes
May 27, 2026
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Summary
Fixes a bug in the streaming
<thinking>-tag state machine where<thinking>appearing inside a fenced code block (```or~~~) or an inline backtick span was incorrectly treated as the start of a thinking/reasoning block, causing that content to disappear from the visible output into an invisible panel.Two related bugs are fixed:
Fenced code block exclusion (streaming). The state machine now enters a "fence" mode when it encounters a fenced code block opener, treating all content until the matching closer as plain text. Fence state is persisted across chunk boundaries so split chunks work correctly.
Chunk-boundary false positive. A chunk ending with a non-whitespace character (e.g., a backtick in
`<thinking>`) followed by a new chunk starting with<thinking>previously entered thinking mode incorrectly becausebefore.trim() === ""was the only guard. The fix also requires a newline boundary to precede the tag.Inline code span exclusion (non-streaming). The full-message path now also excludes inline backtick spans (
`...`) from thinking-tag detection, matching the existing fenced-block exclusion.Four new test cases cover: (1) chunk-boundary false positive, (2) valid cross-chunk
<thinking>after a real newline, (3) inline code span exclusion, and (4) fenced code block exclusion during streaming.Verification
Construct a message that includes
<thinking>inside a fenced code block, e.g. from a model that uses XML-style reasoning syntax or by appending a chunk manually:Previously the content inside the fence would vanish into an invisible thinking panel. After this fix, it renders as plain code content.