fix(desktop): keep bare loopback URLs in assistant prose

A loopback URL the model writes into a sentence is user-facing content:
"the dev server is at http://localhost:3000" rendered with the address
deleted. The prose pass stripped any bare loopback URL that lacked a
path segment, so only the fenced preview hand-off path survived. Drop
the prose-strip regex; the only remaining suppression is a fenced block
whose whole body is the loopback URL (LOCAL_PREVIEW_ONLY_RE), which the
preview widget already paints.

Fixes https://github.com/NousResearch/hermes-agent/issues/121683

apps/desktop/src/components/assistant-ui/markdown-text.test.ts

@@ -16,8 +16,9 @@ describe('preprocessMarkdown', () => {
 
     expect(output).not.toContain('```')
     expect(output).toContain("Here's your scene:")
-    // Bare localhost URLs (with or without trailing slash) are still stripped.
-    expect(output).not.toContain('http://localhost:8812/')
+    // Loopback URLs in prose are user-facing content (#121683): the address
+    // autolinks instead of being deleted from the sentence.
+    expect(output).toContain('<http://localhost:8812/>')
     expect(output).toContain('- **Multicolored cube**')
   })
 
@@ -34,8 +35,9 @@ describe('preprocessMarkdown', () => {
     const output = preprocessMarkdown(input)
 
     expect(output).not.toContain('```')
-    // Bare localhost URLs (with or without trailing slash) are still stripped.
-    expect(output).not.toContain('http://localhost:8812/')
+    // Loopback URLs in prose are user-facing content (#121683): the address
+    // autolinks instead of being deleted from the sentence.
+    expect(output).toContain('<http://localhost:8812/>')
     expect(output).toContain('- **Scroll wheel** - zoom')
   })
 

apps/desktop/src/lib/markdown-preprocess.autolink.test.ts

@@ -105,6 +105,39 @@ describe('preprocessMarkdown / raw-URL autolinking inside markdown links', () =>
   })
 })
 
+describe('preprocessMarkdown / bare loopback URLs in prose', () => {
+  // A loopback URL the model writes into a sentence is user-facing content —
+  // "the dev server is at http://localhost:3000" must render the address,
+  // not leave a hole (#121683). The only legitimate suppression is the fenced
+  // preview hand-off (a whole fenced block whose body is just the URL),
+  // owned by LOCAL_PREVIEW_ONLY_RE in normalizeFenceBlocks.
+  it.each([
+    ['Bare autolink: http://localhost:3000', 'http://localhost:3000'],
+    ['With a path: http://localhost:3000/dashboard', 'http://localhost:3000/dashboard'],
+    ['Loopback IP: http://127.0.0.1:8080', 'http://127.0.0.1:8080'],
+    ['Wildcard bind: http://0.0.0.0:8000', 'http://0.0.0.0:8000'],
+    ['IPv6 loopback: http://[::1]:8080/status', 'http://[::1]:8080/status'],
+    ['Trailing slash: http://localhost:3000/ - panel', 'http://localhost:3000/'],
+    ['Server at http://localhost:3000 and docs at https://example.com', ['http://localhost:3000', 'https://example.com']]
+  ])('preserves bare loopback URLs in prose: %s', (input, expected) => {
+    expect(hrefs(input)).toEqual([expected].flat())
+  })
+
+  it('keeps a markdown-labeled loopback link intact', () => {
+    const input = '[my dev server](http://localhost:3000)'
+
+    expect(preprocessMarkdown(input)).toBe(input)
+    expect(hrefs(input)).toEqual(['http://localhost:3000'])
+  })
+
+  it('still drops a fenced block whose whole body is a loopback URL (preview hand-off)', () => {
+    const input = 'Before\n\n```\nhttp://localhost:3000\n```\n\nAfter'
+
+    expect(preprocessMarkdown(input)).toBe('Before\n\n\nAfter')
+    expect(hrefs(input)).toEqual([])
+  })
+})
+
 describe('preprocessMarkdown / bare-URL trailing punctuation', () => {
   it.each([
     ['Visit https://example.com/a.', 'https://example.com/a'],

apps/desktop/src/lib/markdown-preprocess.ts

@@ -97,9 +97,12 @@ const MARKDOWN_LINK_SPLIT_RE = new RegExp(
   'gm'
 )
 
-// Only strip bare localhost root URLs in prose. URLs with actual path segments
-// (e.g. http://localhost:8080/piwo) are user-facing content and must survive.
-const LOCAL_PREVIEW_URL_RE = /(^|\s)https?:\/\/(?:localhost|127\.0\.0\.1|0\.0\.0\.0|\[::1\])(?::\d+)?\/?(?=\s|$)/gi
+// A fenced block whose entire body is a loopback URL is the preview-pane
+// hand-off: the widget already paints that address, so the whole block is
+// dropped instead of painting the raw text twice. Bare loopback URLs in
+// PROSE are user-facing content and must survive (#121683) — "dev server at
+// http://localhost:3000" is the address the reader needs, wherever it sits
+// in the sentence.
 const LOCAL_PREVIEW_ONLY_RE = /^https?:\/\/(?:localhost|127\.0\.0\.1|0\.0\.0\.0|\[::1\])(?::\d+)?\/?$/i
 const URL_ONLY_LINE_RE = /^\s*https?:\/\/\S+\s*$/i
 // Autolink-shaped spans (bare or angle-bracketed http(s) URLs) that must be
@@ -445,7 +448,6 @@ function rewriteProseSegment(segment: string): string {
           escapeUnknownHtmlLikeTags(
             segment
               .replace(/`{3,}/g, '')
-              .replace(LOCAL_PREVIEW_URL_RE, '$1')
               .replace(CITATION_TRANSPORT_MARKER_RE, '')
               .replace(CITATION_MARKER_RE, '')
           )