diff --git a/internal/js/helpers/stream-tool-sieve/parse_payload.js b/internal/js/helpers/stream-tool-sieve/parse_payload.js
index 49579f9..05334d3 100644
--- a/internal/js/helpers/stream-tool-sieve/parse_payload.js
+++ b/internal/js/helpers/stream-tool-sieve/parse_payload.js
@@ -1,8 +1,5 @@
 'use strict';
 
-const TOOLS_WRAPPER_PATTERN = /<tool_calls\b[^>]*>([\s\S]*?)<\/tool_calls>/gi;
-const TOOL_CALL_MARKUP_BLOCK_PATTERN = /<(?:[a-z0-9_:-]+:)?invoke\b([^>]*)>([\s\S]*?)<\/(?:[a-z0-9_:-]+:)?invoke>/gi;
-const PARAMETER_BLOCK_PATTERN = /<(?:[a-z0-9_:-]+:)?parameter\b([^>]*)>([\s\S]*?)<\/(?:[a-z0-9_:-]+:)?parameter>/gi;
 const TOOL_CALL_MARKUP_KV_PATTERN = /<(?:[a-z0-9_:-]+:)?([a-z0-9_.-]+)\b[^>]*>([\s\S]*?)<\/(?:[a-z0-9_:-]+:)?\1>/gi;
 const CDATA_PATTERN = /^<!\[CDATA\[([\s\S]*?)]]>$/i;
 const XML_ATTR_PATTERN = /\b([a-z0-9_:-]+)\s*=\s*("([^"]*)"|'([^']*)')/gi;
@@ -25,9 +22,9 @@ function parseMarkupToolCalls(text) {
     return [];
   }
   const out = [];
-  for (const wrapper of raw.matchAll(TOOLS_WRAPPER_PATTERN)) {
-    const body = toStringSafe(wrapper[1]);
-    for (const block of body.matchAll(TOOL_CALL_MARKUP_BLOCK_PATTERN)) {
+  for (const wrapper of findXmlElementBlocks(raw, 'tool_calls')) {
+    const body = toStringSafe(wrapper.body);
+    for (const block of findXmlElementBlocks(body, 'invoke')) {
       const parsed = parseMarkupSingleToolCall(block);
       if (parsed) {
         out.push(parsed);
@@ -38,12 +35,12 @@ function parseMarkupToolCalls(text) {
 }
 
 function parseMarkupSingleToolCall(block) {
-  const attrs = parseTagAttributes(block[1]);
+  const attrs = parseTagAttributes(block.attrs);
   const name = toStringSafe(attrs.name).trim();
   if (!name) {
     return null;
   }
-  const inner = toStringSafe(block[2]).trim();
+  const inner = toStringSafe(block.body).trim();
 
   if (inner) {
     try {
@@ -63,13 +60,13 @@ function parseMarkupSingleToolCall(block) {
     }
   }
   const input = {};
-  for (const match of inner.matchAll(PARAMETER_BLOCK_PATTERN)) {
-    const parameterAttrs = parseTagAttributes(match[1]);
+  for (const match of findXmlElementBlocks(inner, 'parameter')) {
+    const parameterAttrs = parseTagAttributes(match.attrs);
     const paramName = toStringSafe(parameterAttrs.name).trim();
     if (!paramName) {
       continue;
     }
-    appendMarkupValue(input, paramName, parseMarkupValue(match[2]));
+    appendMarkupValue(input, paramName, parseMarkupValue(match.body));
   }
   if (Object.keys(input).length === 0 && inner.trim() !== '') {
     return null;
@@ -77,6 +74,154 @@ function parseMarkupSingleToolCall(block) {
   return { name, input };
 }
 
+function findXmlElementBlocks(text, tag) {
+  const source = toStringSafe(text);
+  const name = toStringSafe(tag).toLowerCase();
+  if (!source || !name) {
+    return [];
+  }
+  const out = [];
+  let pos = 0;
+  while (pos < source.length) {
+    const start = findXmlStartTagOutsideCDATA(source, name, pos);
+    if (!start) {
+      break;
+    }
+    const end = findMatchingXmlEndTagOutsideCDATA(source, name, start.bodyStart);
+    if (!end) {
+      break;
+    }
+    out.push({
+      attrs: start.attrs,
+      body: source.slice(start.bodyStart, end.closeStart),
+      start: start.start,
+      end: end.closeEnd,
+    });
+    pos = end.closeEnd;
+  }
+  return out;
+}
+
+function findXmlStartTagOutsideCDATA(text, tag, from) {
+  const lower = text.toLowerCase();
+  const target = `<${tag}`;
+  for (let i = Math.max(0, from || 0); i < text.length;) {
+    const skipped = skipXmlIgnoredSection(lower, i);
+    if (skipped.blocked) {
+      return null;
+    }
+    if (skipped.advanced) {
+      i = skipped.next;
+      continue;
+    }
+    if (lower.startsWith(target, i) && hasXmlTagBoundary(text, i + target.length)) {
+      const tagEnd = findXmlTagEnd(text, i + target.length);
+      if (tagEnd < 0) {
+        return null;
+      }
+      return {
+        start: i,
+        bodyStart: tagEnd + 1,
+        attrs: text.slice(i + target.length, tagEnd),
+      };
+    }
+    i += 1;
+  }
+  return null;
+}
+
+function findMatchingXmlEndTagOutsideCDATA(text, tag, from) {
+  const lower = text.toLowerCase();
+  const openTarget = `<${tag}`;
+  const closeTarget = `</${tag}`;
+  let depth = 1;
+  for (let i = Math.max(0, from || 0); i < text.length;) {
+    const skipped = skipXmlIgnoredSection(lower, i);
+    if (skipped.blocked) {
+      return null;
+    }
+    if (skipped.advanced) {
+      i = skipped.next;
+      continue;
+    }
+    if (lower.startsWith(closeTarget, i) && hasXmlTagBoundary(text, i + closeTarget.length)) {
+      const tagEnd = findXmlTagEnd(text, i + closeTarget.length);
+      if (tagEnd < 0) {
+        return null;
+      }
+      depth -= 1;
+      if (depth === 0) {
+        return { closeStart: i, closeEnd: tagEnd + 1 };
+      }
+      i = tagEnd + 1;
+      continue;
+    }
+    if (lower.startsWith(openTarget, i) && hasXmlTagBoundary(text, i + openTarget.length)) {
+      const tagEnd = findXmlTagEnd(text, i + openTarget.length);
+      if (tagEnd < 0) {
+        return null;
+      }
+      if (!isSelfClosingXmlTag(text.slice(i, tagEnd))) {
+        depth += 1;
+      }
+      i = tagEnd + 1;
+      continue;
+    }
+    i += 1;
+  }
+  return null;
+}
+
+function skipXmlIgnoredSection(lower, i) {
+  if (lower.startsWith('<![cdata[', i)) {
+    const end = lower.indexOf(']]>', i + '<![cdata['.length);
+    if (end < 0) {
+      return { advanced: false, blocked: true, next: i };
+    }
+    return { advanced: true, blocked: false, next: end + ']]>'.length };
+  }
+  if (lower.startsWith('<!--', i)) {
+    const end = lower.indexOf('-->', i + '<!--'.length);
+    if (end < 0) {
+      return { advanced: false, blocked: true, next: i };
+    }
+    return { advanced: true, blocked: false, next: end + '-->'.length };
+  }
+  return { advanced: false, blocked: false, next: i };
+}
+
+function findXmlTagEnd(text, from) {
+  let quote = '';
+  for (let i = Math.max(0, from || 0); i < text.length; i += 1) {
+    const ch = text[i];
+    if (quote) {
+      if (ch === quote) {
+        quote = '';
+      }
+      continue;
+    }
+    if (ch === '"' || ch === "'") {
+      quote = ch;
+      continue;
+    }
+    if (ch === '>') {
+      return i;
+    }
+  }
+  return -1;
+}
+
+function hasXmlTagBoundary(text, idx) {
+  if (idx >= text.length) {
+    return true;
+  }
+  return [' ', '\t', '\n', '\r', '>', '/'].includes(text[idx]);
+}
+
+function isSelfClosingXmlTag(startTag) {
+  return toStringSafe(startTag).trim().endsWith('/');
+}
+
 function parseMarkupInput(raw) {
   const s = toStringSafe(raw).trim();
   if (!s) {
@@ -120,6 +265,10 @@ function parseMarkupKVObject(text) {
 }
 
 function parseMarkupValue(raw) {
+  const cdata = extractStandaloneCDATA(raw);
+  if (cdata.ok) {
+    return cdata.value;
+  }
   const s = toStringSafe(extractRawTagValue(raw)).trim();
   if (!s) {
     return '';
@@ -152,9 +301,9 @@ function extractRawTagValue(inner) {
   }
 
   // 1. Check for CDATA
-  const cdataMatch = s.match(CDATA_PATTERN);
-  if (cdataMatch && cdataMatch[1] !== undefined) {
-    return cdataMatch[1];
+  const cdata = extractStandaloneCDATA(s);
+  if (cdata.ok) {
+    return cdata.value;
   }
 
   // 2. Fallback to unescaping standard HTML entities
@@ -172,6 +321,15 @@ function unescapeHtml(safe) {
     .replace(/&#x27;/g, "'");
 }
 
+function extractStandaloneCDATA(inner) {
+  const s = toStringSafe(inner).trim();
+  const cdataMatch = s.match(CDATA_PATTERN);
+  if (cdataMatch && cdataMatch[1] !== undefined) {
+    return { ok: true, value: cdataMatch[1] };
+  }
+  return { ok: false, value: '' };
+}
+
 function parseTagAttributes(raw) {
   const source = toStringSafe(raw);
   const out = {};
diff --git a/internal/js/helpers/stream-tool-sieve/sieve-xml.js b/internal/js/helpers/stream-tool-sieve/sieve-xml.js
index cc8ee43..90ea280 100644
--- a/internal/js/helpers/stream-tool-sieve/sieve-xml.js
+++ b/internal/js/helpers/stream-tool-sieve/sieve-xml.js
@@ -16,9 +16,10 @@ function consumeXMLToolCapture(captured, toolNames, trimWrappingJSONFence) {
     if (openIdx < 0) {
       continue;
     }
-    // Find the LAST occurrence of the specific closing tag.
-    const closeIdx = lower.lastIndexOf(pair.close);
-    if (closeIdx < openIdx) {
+    // Ignore closing tags that appear inside CDATA payloads, such as
+    // write-file content containing tool-call documentation examples.
+    const closeIdx = findXMLCloseOutsideCDATA(captured, pair.close, openIdx + pair.open.length);
+    if (closeIdx < 0) {
       // Opening tag present but specific closing tag hasn't arrived.
       // Return not-ready so buffering continues until the wrapper closes.
       return { ready: false, prefix: '', calls: [], suffix: '' };
@@ -46,8 +47,9 @@ function consumeXMLToolCapture(captured, toolNames, trimWrappingJSONFence) {
 function hasOpenXMLToolTag(captured) {
   const lower = captured.toLowerCase();
   for (const pair of XML_TOOL_TAG_PAIRS) {
-    if (lower.includes(pair.open)) {
-      if (!lower.includes(pair.close)) {
+    const openIdx = lower.indexOf(pair.open);
+    if (openIdx >= 0) {
+      if (findXMLCloseOutsideCDATA(captured, pair.close, openIdx + pair.open.length) < 0) {
         return true;
       }
     }
@@ -74,6 +76,38 @@ function findPartialXMLToolTagStart(s) {
   return -1;
 }
 
+function findXMLCloseOutsideCDATA(s, closeTag, start) {
+  const text = typeof s === 'string' ? s : '';
+  const target = String(closeTag || '').toLowerCase();
+  if (!text || !target) {
+    return -1;
+  }
+  const lower = text.toLowerCase();
+  for (let i = Math.max(0, start || 0); i < text.length;) {
+    if (lower.startsWith('<![cdata[', i)) {
+      const end = lower.indexOf(']]>', i + '<![cdata['.length);
+      if (end < 0) {
+        return -1;
+      }
+      i = end + ']]>'.length;
+      continue;
+    }
+    if (lower.startsWith('<!--', i)) {
+      const end = lower.indexOf('-->', i + '<!--'.length);
+      if (end < 0) {
+        return -1;
+      }
+      i = end + '-->'.length;
+      continue;
+    }
+    if (lower.startsWith(target, i)) {
+      return i;
+    }
+    i += 1;
+  }
+  return -1;
+}
+
 module.exports = {
   consumeXMLToolCapture,
   hasOpenXMLToolTag,
diff --git a/internal/toolcall/toolcalls_markup.go b/internal/toolcall/toolcalls_markup.go
index 3d8e657..b01ba21 100644
--- a/internal/toolcall/toolcalls_markup.go
+++ b/internal/toolcall/toolcalls_markup.go
@@ -43,6 +43,9 @@ func parseMarkupKVObject(text string) map[string]any {
 }
 
 func parseMarkupValue(inner string) any {
+	if value, ok := extractStandaloneCDATA(inner); ok {
+		return value
+	}
 	value := strings.TrimSpace(extractRawTagValue(inner))
 	if value == "" {
 		return ""
@@ -89,8 +92,8 @@ func extractRawTagValue(inner string) string {
 	}
 
 	// 1. Check for CDATA - if present, it's the ultimate "safe" container.
-	if cdataMatches := cdataPattern.FindStringSubmatch(trimmed); len(cdataMatches) >= 2 {
-		return cdataMatches[1] // Return raw content between CDATA brackets
+	if value, ok := extractStandaloneCDATA(trimmed); ok {
+		return value // Return raw content between CDATA brackets
 	}
 
 	// 2. If no CDATA, we still want to be robust.
@@ -102,3 +105,11 @@ func extractRawTagValue(inner string) string {
 	// but for KV objects we usually want the value.
 	return html.UnescapeString(inner)
 }
+
+func extractStandaloneCDATA(inner string) (string, bool) {
+	trimmed := strings.TrimSpace(inner)
+	if cdataMatches := cdataPattern.FindStringSubmatch(trimmed); len(cdataMatches) >= 2 {
+		return cdataMatches[1], true
+	}
+	return "", false
+}
diff --git a/internal/toolcall/toolcalls_parse.go b/internal/toolcall/toolcalls_parse.go
index 16743ac..a950c2c 100644
--- a/internal/toolcall/toolcalls_parse.go
+++ b/internal/toolcall/toolcalls_parse.go
@@ -87,7 +87,13 @@ func stripFencedCodeBlocks(text string) string {
 	lines := strings.SplitAfter(text, "\n")
 	inFence := false
 	fenceMarker := ""
+	inCDATA := false
 	for _, line := range lines {
+		if inCDATA || cdataStartsBeforeFence(line) {
+			b.WriteString(line)
+			inCDATA = updateCDATAState(inCDATA, line)
+			continue
+		}
 		trimmed := strings.TrimLeft(line, " \t")
 		if !inFence {
 			if marker, ok := parseFenceOpen(trimmed); ok {
@@ -111,6 +117,54 @@ func stripFencedCodeBlocks(text string) string {
 	return b.String()
 }
 
+func cdataStartsBeforeFence(line string) bool {
+	cdataIdx := strings.Index(strings.ToLower(line), "<![cdata[")
+	if cdataIdx < 0 {
+		return false
+	}
+	fenceIdx := firstFenceMarkerIndex(line)
+	return fenceIdx < 0 || cdataIdx < fenceIdx
+}
+
+func firstFenceMarkerIndex(line string) int {
+	idxBacktick := strings.Index(line, "```")
+	idxTilde := strings.Index(line, "~~~")
+	switch {
+	case idxBacktick < 0:
+		return idxTilde
+	case idxTilde < 0:
+		return idxBacktick
+	case idxBacktick < idxTilde:
+		return idxBacktick
+	default:
+		return idxTilde
+	}
+}
+
+func updateCDATAState(inCDATA bool, line string) bool {
+	lower := strings.ToLower(line)
+	pos := 0
+	state := inCDATA
+	for pos < len(lower) {
+		if state {
+			end := strings.Index(lower[pos:], "]]>")
+			if end < 0 {
+				return true
+			}
+			pos += end + len("]]>")
+			state = false
+			continue
+		}
+		start := strings.Index(lower[pos:], "<![cdata[")
+		if start < 0 {
+			return false
+		}
+		pos += start + len("<![cdata[")
+		state = true
+	}
+	return state
+}
+
 func parseFenceOpen(line string) (string, bool) {
 	if len(line) < 3 {
 		return "", false
diff --git a/internal/toolcall/toolcalls_parse_markup.go b/internal/toolcall/toolcalls_parse_markup.go
index 2a9c441..9c4edd3 100644
--- a/internal/toolcall/toolcalls_parse_markup.go
+++ b/internal/toolcall/toolcalls_parse_markup.go
@@ -7,19 +7,16 @@ import (
 	"strings"
 )
 
-var xmlToolCallsWrapperPattern = regexp.MustCompile(`(?is)<tool_calls\b[^>]*>\s*(.*?)\s*</tool_calls>`)
-var xmlInvokePattern = regexp.MustCompile(`(?is)<invoke\b([^>]*)>\s*(.*?)\s*</invoke>`)
-var xmlParameterPattern = regexp.MustCompile(`(?is)<parameter\b([^>]*)>\s*(.*?)\s*</parameter>`)
 var xmlAttrPattern = regexp.MustCompile(`(?is)\b([a-z0-9_:-]+)\s*=\s*("([^"]*)"|'([^']*)')`)
 var xmlToolCallsClosePattern = regexp.MustCompile(`(?is)</tool_calls>`)
 var xmlInvokeStartPattern = regexp.MustCompile(`(?is)<invoke\b[^>]*\bname\s*=\s*("([^"]*)"|'([^']*)')`)
 
 func parseXMLToolCalls(text string) []ParsedToolCall {
-	wrappers := xmlToolCallsWrapperPattern.FindAllStringSubmatch(text, -1)
+	wrappers := findXMLElementBlocks(text, "tool_calls")
 	if len(wrappers) == 0 {
 		repaired := repairMissingXMLToolCallsOpeningWrapper(text)
 		if repaired != text {
-			wrappers = xmlToolCallsWrapperPattern.FindAllStringSubmatch(repaired, -1)
+			wrappers = findXMLElementBlocks(repaired, "tool_calls")
 		}
 	}
 	if len(wrappers) == 0 {
@@ -27,10 +24,7 @@ func parseXMLToolCalls(text string) []ParsedToolCall {
 	}
 	out := make([]ParsedToolCall, 0, len(wrappers))
 	for _, wrapper := range wrappers {
-		if len(wrapper) < 2 {
-			continue
-		}
-		for _, block := range xmlInvokePattern.FindAllStringSubmatch(wrapper[1], -1) {
+		for _, block := range findXMLElementBlocks(wrapper.Body, "invoke") {
 			call, ok := parseSingleXMLToolCall(block)
 			if !ok {
 				continue
@@ -66,17 +60,14 @@ func repairMissingXMLToolCallsOpeningWrapper(text string) string {
 	return text[:invokeLoc[0]] + "<tool_calls>" + text[invokeLoc[0]:closeLoc[0]] + "</tool_calls>" + text[closeLoc[1]:]
 }
 
-func parseSingleXMLToolCall(block []string) (ParsedToolCall, bool) {
-	if len(block) < 3 {
-		return ParsedToolCall{}, false
-	}
-	attrs := parseXMLTagAttributes(block[1])
+func parseSingleXMLToolCall(block xmlElementBlock) (ParsedToolCall, bool) {
+	attrs := parseXMLTagAttributes(block.Attrs)
 	name := strings.TrimSpace(html.UnescapeString(attrs["name"]))
 	if name == "" {
 		return ParsedToolCall{}, false
 	}
 
-	inner := strings.TrimSpace(block[2])
+	inner := strings.TrimSpace(block.Body)
 	if strings.HasPrefix(inner, "{") {
 		var payload map[string]any
 		if err := json.Unmarshal([]byte(inner), &payload); err == nil {
@@ -94,16 +85,13 @@ func parseSingleXMLToolCall(block []string) (ParsedToolCall, bool) {
 	}
 
 	input := map[string]any{}
-	for _, paramMatch := range xmlParameterPattern.FindAllStringSubmatch(inner, -1) {
-		if len(paramMatch) < 3 {
-			continue
-		}
-		paramAttrs := parseXMLTagAttributes(paramMatch[1])
+	for _, paramMatch := range findXMLElementBlocks(inner, "parameter") {
+		paramAttrs := parseXMLTagAttributes(paramMatch.Attrs)
 		paramName := strings.TrimSpace(html.UnescapeString(paramAttrs["name"]))
 		if paramName == "" {
 			continue
 		}
-		value := parseInvokeParameterValue(paramMatch[2])
+		value := parseInvokeParameterValue(paramMatch.Body)
 		appendMarkupValue(input, paramName, value)
 	}
 
@@ -116,6 +104,168 @@ func parseSingleXMLToolCall(block []string) (ParsedToolCall, bool) {
 	return ParsedToolCall{Name: name, Input: input}, true
 }
 
+type xmlElementBlock struct {
+	Attrs string
+	Body  string
+	Start int
+	End   int
+}
+
+func findXMLElementBlocks(text, tag string) []xmlElementBlock {
+	if text == "" || tag == "" {
+		return nil
+	}
+	var out []xmlElementBlock
+	pos := 0
+	for pos < len(text) {
+		start, bodyStart, attrs, ok := findXMLStartTagOutsideCDATA(text, tag, pos)
+		if !ok {
+			break
+		}
+		closeStart, closeEnd, ok := findMatchingXMLEndTagOutsideCDATA(text, tag, bodyStart)
+		if !ok {
+			break
+		}
+		out = append(out, xmlElementBlock{
+			Attrs: attrs,
+			Body:  text[bodyStart:closeStart],
+			Start: start,
+			End:   closeEnd,
+		})
+		pos = closeEnd
+	}
+	return out
+}
+
+func findXMLStartTagOutsideCDATA(text, tag string, from int) (start, bodyStart int, attrs string, ok bool) {
+	lower := strings.ToLower(text)
+	target := "<" + strings.ToLower(tag)
+	for i := maxInt(from, 0); i < len(text); {
+		next, advanced, blocked := skipXMLIgnoredSection(lower, i)
+		if blocked {
+			return -1, -1, "", false
+		}
+		if advanced {
+			i = next
+			continue
+		}
+		if strings.HasPrefix(lower[i:], target) && hasXMLTagBoundary(text, i+len(target)) {
+			end := findXMLTagEnd(text, i+len(target))
+			if end < 0 {
+				return -1, -1, "", false
+			}
+			return i, end + 1, text[i+len(target) : end], true
+		}
+		i++
+	}
+	return -1, -1, "", false
+}
+
+func findMatchingXMLEndTagOutsideCDATA(text, tag string, from int) (closeStart, closeEnd int, ok bool) {
+	lower := strings.ToLower(text)
+	openTarget := "<" + strings.ToLower(tag)
+	closeTarget := "</" + strings.ToLower(tag)
+	depth := 1
+	for i := maxInt(from, 0); i < len(text); {
+		next, advanced, blocked := skipXMLIgnoredSection(lower, i)
+		if blocked {
+			return -1, -1, false
+		}
+		if advanced {
+			i = next
+			continue
+		}
+		if strings.HasPrefix(lower[i:], closeTarget) && hasXMLTagBoundary(text, i+len(closeTarget)) {
+			end := findXMLTagEnd(text, i+len(closeTarget))
+			if end < 0 {
+				return -1, -1, false
+			}
+			depth--
+			if depth == 0 {
+				return i, end + 1, true
+			}
+			i = end + 1
+			continue
+		}
+		if strings.HasPrefix(lower[i:], openTarget) && hasXMLTagBoundary(text, i+len(openTarget)) {
+			end := findXMLTagEnd(text, i+len(openTarget))
+			if end < 0 {
+				return -1, -1, false
+			}
+			if !isSelfClosingXMLTag(text[:end]) {
+				depth++
+			}
+			i = end + 1
+			continue
+		}
+		i++
+	}
+	return -1, -1, false
+}
+
+func skipXMLIgnoredSection(lower string, i int) (next int, advanced bool, blocked bool) {
+	switch {
+	case strings.HasPrefix(lower[i:], "<![cdata["):
+		end := strings.Index(lower[i+len("<![cdata["):], "]]>")
+		if end < 0 {
+			return 0, false, true
+		}
+		return i + len("<![cdata[") + end + len("]]>"), true, false
+	case strings.HasPrefix(lower[i:], "<!--"):
+		end := strings.Index(lower[i+len("<!--"):], "-->")
+		if end < 0 {
+			return 0, false, true
+		}
+		return i + len("<!--") + end + len("-->"), true, false
+	default:
+		return i, false, false
+	}
+}
+
+func findXMLTagEnd(text string, from int) int {
+	quote := byte(0)
+	for i := maxInt(from, 0); i < len(text); i++ {
+		ch := text[i]
+		if quote != 0 {
+			if ch == quote {
+				quote = 0
+			}
+			continue
+		}
+		if ch == '"' || ch == '\'' {
+			quote = ch
+			continue
+		}
+		if ch == '>' {
+			return i
+		}
+	}
+	return -1
+}
+
+func hasXMLTagBoundary(text string, idx int) bool {
+	if idx >= len(text) {
+		return true
+	}
+	switch text[idx] {
+	case ' ', '\t', '\n', '\r', '>', '/':
+		return true
+	default:
+		return false
+	}
+}
+
+func isSelfClosingXMLTag(startTag string) bool {
+	return strings.HasSuffix(strings.TrimSpace(startTag), "/")
+}
+
+func maxInt(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
 func parseXMLTagAttributes(raw string) map[string]string {
 	if strings.TrimSpace(raw) == "" {
 		return map[string]string{}
@@ -143,6 +293,9 @@ func parseInvokeParameterValue(raw string) any {
 	if trimmed == "" {
 		return ""
 	}
+	if value, ok := extractStandaloneCDATA(trimmed); ok {
+		return value
+	}
 	if parsed := parseStructuredToolCallInput(trimmed); len(parsed) > 0 {
 		if len(parsed) == 1 {
 			if rawValue, ok := parsed["_raw"].(string); ok {
diff --git a/internal/toolcall/toolcalls_test.go b/internal/toolcall/toolcalls_test.go
index 8d26f73..c4bfe51 100644
--- a/internal/toolcall/toolcalls_test.go
+++ b/internal/toolcall/toolcalls_test.go
@@ -54,6 +54,32 @@ echo "hello"
 	}
 }
 
+func TestParseToolCallsKeepsToolSyntaxInsideCDATAAsParameterText(t *testing.T) {
+	payload := strings.Join([]string{
+		"# Release notes",
+		"",
+		"```xml",
+		"<tool_calls>",
+		"  <invoke name=\"demo\">",
+		"    <parameter name=\"value\">x</parameter>",
+		"  </invoke>",
+		"</tool_calls>",
+		"```",
+	}, "\n")
+	text := `<tool_calls><invoke name="Write"><parameter name="content"><![CDATA[` + payload + `]]></parameter><parameter name="file_path">DS2API-4.0-Release-Notes.md</parameter></invoke></tool_calls>`
+	calls := ParseToolCalls(text, []string{"Write"})
+	if len(calls) != 1 {
+		t.Fatalf("expected 1 call, got %#v", calls)
+	}
+	content, _ := calls[0].Input["content"].(string)
+	if content != payload {
+		t.Fatalf("expected CDATA payload with nested tool syntax to survive intact, got %q", content)
+	}
+	if calls[0].Input["file_path"] != "DS2API-4.0-Release-Notes.md" {
+		t.Fatalf("expected file_path parameter, got %#v", calls[0].Input)
+	}
+}
+
 func TestParseToolCallsSupportsInvokeParameters(t *testing.T) {
 	text := `<tool_calls><invoke name="get_weather"><parameter name="city">beijing</parameter><parameter name="unit">c</parameter></invoke></tool_calls>`
 	calls := ParseToolCalls(text, []string{"get_weather"})
diff --git a/internal/toolstream/tool_sieve_xml.go b/internal/toolstream/tool_sieve_xml.go
index 6d6cbc4..72cbbaa 100644
--- a/internal/toolstream/tool_sieve_xml.go
+++ b/internal/toolstream/tool_sieve_xml.go
@@ -35,9 +35,10 @@ func consumeXMLToolCapture(captured string, toolNames []string) (prefix string,
 		if openIdx < 0 {
 			continue
 		}
-		// Find the LAST occurrence of the specific closing tag to get the outermost block.
-		closeIdx := strings.LastIndex(lower, pair.close)
-		if closeIdx < openIdx {
+		// Find the matching closing tag outside CDATA. Long write-file tool
+		// calls often contain XML examples in CDATA, including </tool_calls>.
+		closeIdx := findXMLCloseOutsideCDATA(captured, pair.close, openIdx+len(pair.open))
+		if closeIdx < 0 {
 			// Opening tag is present but its specific closing tag hasn't arrived.
 			// Return not-ready so we keep buffering until the canonical wrapper closes.
 			return "", nil, "", false
@@ -57,7 +58,7 @@ func consumeXMLToolCapture(captured string, toolNames []string) (prefix string,
 	}
 	if !strings.Contains(lower, "<tool_calls") {
 		invokeIdx := strings.Index(lower, "<invoke")
-		closeIdx := strings.LastIndex(lower, "</tool_calls>")
+		closeIdx := findXMLCloseOutsideCDATA(captured, "</tool_calls>", invokeIdx)
 		if invokeIdx >= 0 && closeIdx > invokeIdx {
 			closeEnd := closeIdx + len("</tool_calls>")
 			xmlBlock := "<tool_calls>" + captured[invokeIdx:closeIdx] + "</tool_calls>"
@@ -79,8 +80,9 @@ func consumeXMLToolCapture(captured string, toolNames []string) (prefix string,
 func hasOpenXMLToolTag(captured string) bool {
 	lower := strings.ToLower(captured)
 	for _, pair := range xmlToolCallTagPairs {
-		if strings.Contains(lower, pair.open) {
-			if !strings.Contains(lower, pair.close) {
+		openIdx := strings.Index(lower, pair.open)
+		if openIdx >= 0 {
+			if findXMLCloseOutsideCDATA(captured, pair.close, openIdx+len(pair.open)) < 0 {
 				return true
 			}
 		}
@@ -88,6 +90,38 @@ func hasOpenXMLToolTag(captured string) bool {
 	return false
 }
 
+func findXMLCloseOutsideCDATA(s, closeTag string, start int) int {
+	if s == "" || closeTag == "" {
+		return -1
+	}
+	if start < 0 {
+		start = 0
+	}
+	lower := strings.ToLower(s)
+	target := strings.ToLower(closeTag)
+	for i := start; i < len(s); {
+		switch {
+		case strings.HasPrefix(lower[i:], "<![cdata["):
+			end := strings.Index(lower[i+len("<![cdata["):], "]]>")
+			if end < 0 {
+				return -1
+			}
+			i += len("<![cdata[") + end + len("]]>")
+		case strings.HasPrefix(lower[i:], "<!--"):
+			end := strings.Index(lower[i+len("<!--"):], "-->")
+			if end < 0 {
+				return -1
+			}
+			i += len("<!--") + end + len("-->")
+		case strings.HasPrefix(lower[i:], target):
+			return i
+		default:
+			i++
+		}
+	}
+	return -1
+}
+
 // findPartialXMLToolTagStart checks if the string ends with a partial canonical
 // XML wrapper tag (e.g., "<too") and returns the position of the '<'.
 func findPartialXMLToolTagStart(s string) int {
diff --git a/internal/toolstream/tool_sieve_xml_test.go b/internal/toolstream/tool_sieve_xml_test.go
index ba4a00b..87e79b5 100644
--- a/internal/toolstream/tool_sieve_xml_test.go
+++ b/internal/toolstream/tool_sieve_xml_test.go
@@ -84,6 +84,65 @@ func TestProcessToolSieveHandlesLongXMLToolCall(t *testing.T) {
 	}
 }
 
+func TestProcessToolSieveKeepsCDATAEmbeddedToolClosingBuffered(t *testing.T) {
+	var state State
+	payload := strings.Join([]string{
+		"# DS2API 4.0 更新内容",
+		"",
+		strings.Repeat("x", 4096),
+		"```xml",
+		"<tool_calls>",
+		"  <invoke name=\"demo\">",
+		"    <parameter name=\"value\">x</parameter>",
+		"  </invoke>",
+		"</tool_calls>",
+		"```",
+		"tail",
+	}, "\n")
+	innerClose := strings.Index(payload, "</tool_calls>") + len("</tool_calls>")
+	chunks := []string{
+		"<tool_calls>\n  <invoke name=\"Write\">\n    <parameter name=\"content\"><![CDATA[",
+		payload[:innerClose],
+		payload[innerClose:],
+		"]]></parameter>\n    <parameter name=\"file_path\">DS2API-4.0-Release-Notes.md</parameter>\n  </invoke>\n</tool_calls>",
+	}
+
+	var events []Event
+	for i, c := range chunks {
+		next := ProcessChunk(&state, c, []string{"Write"})
+		if i <= 1 {
+			for _, evt := range next {
+				if evt.Content != "" || len(evt.ToolCalls) > 0 {
+					t.Fatalf("expected no events before outer closing tag, chunk=%d events=%#v", i, next)
+				}
+			}
+		}
+		events = append(events, next...)
+	}
+	events = append(events, Flush(&state, []string{"Write"})...)
+
+	var textContent strings.Builder
+	var gotPayload string
+	toolCalls := 0
+	for _, evt := range events {
+		textContent.WriteString(evt.Content)
+		if len(evt.ToolCalls) > 0 {
+			toolCalls += len(evt.ToolCalls)
+			gotPayload, _ = evt.ToolCalls[0].Input["content"].(string)
+		}
+	}
+
+	if toolCalls != 1 {
+		t.Fatalf("expected one parsed tool call, got %d events=%#v", toolCalls, events)
+	}
+	if textContent.Len() != 0 {
+		t.Fatalf("expected no leaked text, got %q", textContent.String())
+	}
+	if gotPayload != payload {
+		t.Fatalf("expected full CDATA payload to survive intact, got len=%d want=%d", len(gotPayload), len(payload))
+	}
+}
+
 func TestProcessToolSieveXMLWithLeadingText(t *testing.T) {
 	var state State
 	// Model outputs some prose then an XML tool call.
diff --git a/tests/node/stream-tool-sieve.test.js b/tests/node/stream-tool-sieve.test.js
index 1e5012a..cc6ae93 100644
--- a/tests/node/stream-tool-sieve.test.js
+++ b/tests/node/stream-tool-sieve.test.js
@@ -118,6 +118,60 @@ test('sieve keeps long XML tool calls buffered until the closing tag arrives', (
   assert.equal(finalCalls[0].input.content, longContent);
 });
 
+test('sieve keeps CDATA tool examples buffered until the outer closing tag arrives', () => {
+  const content = [
+    '# DS2API 4.0 更新内容',
+    '',
+    'x'.repeat(4096),
+    '```xml',
+    '<tool_calls>',
+    '  <invoke name="demo">',
+    '    <parameter name="value">x</parameter>',
+    '  </invoke>',
+    '</tool_calls>',
+    '```',
+    'tail',
+  ].join('\n');
+  const innerClose = content.indexOf('</tool_calls>') + '</tool_calls>'.length;
+  const state = createToolSieveState();
+  const chunks = [
+    '<tool_calls>\n  <invoke name="Write">\n    <parameter name="content"><![CDATA[',
+    content.slice(0, innerClose),
+    content.slice(innerClose),
+    ']]></parameter>\n    <parameter name="file_path">DS2API-4.0-Release-Notes.md</parameter>\n  </invoke>\n</tool_calls>',
+  ];
+  const events = [];
+  chunks.forEach((chunk, idx) => {
+    const next = processToolSieveChunk(state, chunk, ['Write']);
+    if (idx <= 1) {
+      assert.deepEqual(next, []);
+    }
+    events.push(...next);
+  });
+  events.push(...flushToolSieve(state, ['Write']));
+
+  const leakedText = collectText(events);
+  const finalCalls = events.filter((evt) => evt.type === 'tool_calls').flatMap((evt) => evt.calls || []);
+  assert.equal(leakedText, '');
+  assert.equal(finalCalls.length, 1);
+  assert.equal(finalCalls[0].name, 'Write');
+  assert.equal(finalCalls[0].input.content, content);
+});
+
+test('parseToolCalls keeps XML-looking CDATA content intact', () => {
+  const content = [
+    '# Release notes',
+    '```xml',
+    '<tool_calls><invoke name="demo"><parameter name="value">x</parameter></invoke></tool_calls>',
+    '```',
+  ].join('\n');
+  const payload = `<tool_calls><invoke name="Write"><parameter name="content"><![CDATA[${content}]]></parameter><parameter name="file_path">DS2API-4.0-Release-Notes.md</parameter></invoke></tool_calls>`;
+  const calls = parseToolCalls(payload, ['Write']);
+  assert.equal(calls.length, 1);
+  assert.equal(calls[0].input.content, content);
+  assert.equal(calls[0].input.file_path, 'DS2API-4.0-Release-Notes.md');
+});
+
 test('sieve passes JSON tool_calls payload through as text (XML-only)', () => {
   const events = runSieve(
     ['{"tool_calls":[{"name":"read_file","input":{"path":"README.MD"}}]}'],