anomalyco / anomalyco/opencode

webfetch returns raw XHTML markup instead of converting it

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#45,905 0 comments 0 reactions 1 assignee View on GitHub

@nexxeln is already working on this.

Since Aug 28, 2026.

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Description

Describe the bug

webfetch advertises application/xhtml+xml;q=0.9 in its own Accept header (for format: html), and isTextualMime accepts *+xml mime types, but convert() only treats text/html as HTML:

if (!contentType.includes("text/html")) return content

So a page served as application/xhtml+xml is returned as raw XML tag soup in markdown/"text" formats, with no error (because the mime check passes), leaving the model to consume low-quality markup.

Steps to reproduce

Fetch any URL serving Content-Type: application/xhtml+xml (strict XHTML documents, some CMS/doc generators) with format: "markdown". The output is the untouched <html xmlns=...><body>... source.

Affected code

packages/core/src/tool/webfetch.tsconvert() string-match only recognizes text/html.

Suggested fix

Also treat application/xhtml+xml as HTML in convert().

Environment
  • opencode version: latest dev

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