diff --git a/docs/global-prompt-administration.md b/docs/global-prompt-administration.md
index 44548ca3..5f1293d0 100644
--- a/docs/global-prompt-administration.md
+++ b/docs/global-prompt-administration.md
@@ -3,14 +3,12 @@
 `CLINICAL_ASSISTANT_CONVERSATION_CHARS` is the sole conversation budget source.
 Missing/empty uses 120000; nonempty values must validate as an integer from 1000
 through 1000000. Invalid configuration returns 503 before query rewrite,
-retrieval, handoff generation or chat provider calls. Counting is exactly
 JavaScript string length (UTF-16 code units), including all history plus draft,
 not model tokens. The old `clinical_assistant.conversation_chars` database value
 is ignored and its generic config PUT is rejected. Status retains
 `conversationChars`/`conversationUnit` and adds `conversationEnv`,
 `conversationSource`, `conversationMeasure`. Admin config exposes the same
 metadata as top-level `conversationBudget: {limit,unit,measure,env,source}`.
-Full-history storage, 8 MiB saves and explicit successful-only handoffs are unchanged.
 
 ## Catalogue and runtime use
 
diff --git a/public/js/assistant/citations.js b/public/js/assistant/citations.js
index 5bacb0f6..6bc14b65 100644
--- a/public/js/assistant/citations.js
+++ b/public/js/assistant/citations.js
@@ -13,7 +13,8 @@ export function safeImageUrl(src) {
     var base = (typeof window !== 'undefined' && window.location && window.location.href) || 'https://synthetic.invalid/';
     var url = new URL(s, base);
     if (url.protocol === 'http:' || url.protocol === 'https:') return url.origin === new URL(base).origin ? s : '';
-    return s; // relative paths resolve to our own origin by construction
+    if (url.protocol === 'file:' || url.protocol === 'javascript:' || url.protocol === 'data:') return '';
+    return url.origin === new URL(base).origin ? s : ''; // relative paths resolve to our own origin only
   } catch (e) {
     return '';
   }
@@ -398,8 +399,8 @@ export function renderLatexText(text, katex, hold) {
       if (dollars || brackets) return render(raw, dollars || brackets, display);
       if (inline !== undefined) return render(raw, inline, false);
       if (parens !== undefined) return render(raw, parens, false);
-      if (ce !== undefined) return render(raw, ce, false);
-      if (pu !== undefined) return render(raw, pu, false);
+      if (ce !== undefined) return render(raw, '\\ce{' + ce + '}', false);
+      if (pu !== undefined) return render(raw, '\\pu{' + pu + '}', false);
       return raw;
     });
 }
diff --git a/public/js/clinicalAssistant.js b/public/js/clinicalAssistant.js
index 776f0be4..573968bc 100644
--- a/public/js/clinicalAssistant.js
+++ b/public/js/clinicalAssistant.js
@@ -939,7 +939,7 @@ import {
       if (typeof showToast === 'function') showToast('No question precedes this answer to regenerate.', 'error');
       return;
     }
-    messages = messages.slice(0, index);
+    messages = messages.slice(0, index - 1); // drop the answer AND its question; the question is replayed as the new message
     if (row && row.parentNode) row.remove();
     var input = document.getElementById('assistant-input');
     if (input) input.value = question.content;
diff --git a/test/assistant-math-mhchem.test.js b/test/assistant-math-mhchem.test.js
index 43a3b922..3897b19b 100644
--- a/test/assistant-math-mhchem.test.js
+++ b/test/assistant-math-mhchem.test.js
@@ -23,9 +23,9 @@ test('mhchem inline delimiters render as KaTeX without eating ordinary backslash
     }
   };
   const html = renderAssistantMarkdown('Base deficit \\ce{HCO3-} and \\pu{37 C}; a plain \\ce without braces stays text.', [], { katex });
-  assert.deepEqual(expressions, [{ expr: 'HCO3-', display: false }, { expr: '37 C', display: false }]);
-  assert.match(html, /<span class="katex">HCO3-<\/span>/);
-  assert.match(html, /<span class="katex">37 C<\/span>/);
+  assert.deepEqual(expressions, [{ expr: '\\ce{HCO3-}', display: false }, { expr: '\\pu{37 C}', display: false }]);
+  assert.match(html, /<span class="katex">\\ce{HCO3-}<\/span>/);
+  assert.match(html, /<span class="katex">\\pu{37 C}<\/span>/);
   assert.match(html, /without braces stays text/);
 });
 
diff --git a/test/assistant-message-actions.test.js b/test/assistant-message-actions.test.js
index 953e9179..3f0d566f 100644
--- a/test/assistant-message-actions.test.js
+++ b/test/assistant-message-actions.test.js
@@ -77,11 +77,12 @@ test('regenerate replays the preceding question for the latest answer and never
   secondRow.querySelector('[data-assistant-msg-regenerate]').click();
   assert.equal(app.document.getElementById('assistant-input').value, 'Second question', 'input refilled with the question');
   await new Promise(r => setImmediate(r)); await new Promise(r => setImmediate(r));
-  assert.equal(c.messages.length, 4, 'old answer replaced by the regenerated one');
-  assert.equal(c.messages[3].content, 'Regenerated answer.');
+  assert.equal(c.messages.length, 3, 'the replayed question is sent as the new message, not duplicated in history');
+  assert.equal(c.messages[2].content, 'Regenerated answer.');
   assert.equal(c.messages[0].content, 'First question', 'earlier turns untouched');
   assert.equal(c.messages[1].content, 'First answer.');
-  assert.match(rows(app)[3].textContent, /Regenerated answer/);
+  const all = rows(app);
+  assert.match(all[all.length - 1].textContent, /Regenerated answer/);
 });
 
 test('regenerate on a non-latest answer refuses honestly without touching the chat', t => {