From a32edf423b11948523da58d3cb3a27c19de446e1 Mon Sep 17 00:00:00 2001
From: Peter Steinberger <steipete@gmail.com>
Date: Sat, 21 Feb 2026 22:45:32 +0000
Subject: [PATCH] refactor(text): share code-region parsing for reasoning tags

---
 src/shared/text/code-regions.ts               | 31 +++++++++++++++++
 src/shared/text/reasoning-tags.ts             | 33 +------------------
 .../reasoning-lane-coordinator.test.ts        |  4 +++
 src/telegram/reasoning-lane-coordinator.ts    | 33 +------------------
 4 files changed, 37 insertions(+), 64 deletions(-)
 create mode 100644 src/shared/text/code-regions.ts

diff --git a/src/shared/text/code-regions.ts b/src/shared/text/code-regions.ts
new file mode 100644
index 00000000000..c05328ec70b
--- /dev/null
+++ b/src/shared/text/code-regions.ts
@@ -0,0 +1,31 @@
+export interface CodeRegion {
+  start: number;
+  end: number;
+}
+
+export function findCodeRegions(text: string): CodeRegion[] {
+  const regions: CodeRegion[] = [];
+
+  const fencedRe = /(^|\n)(```|~~~)[^\n]*\n[\s\S]*?(?:\n\2(?:\n|$)|$)/g;
+  for (const match of text.matchAll(fencedRe)) {
+    const start = (match.index ?? 0) + match[1].length;
+    regions.push({ start, end: start + match[0].length - match[1].length });
+  }
+
+  const inlineRe = /`+[^`]+`+/g;
+  for (const match of text.matchAll(inlineRe)) {
+    const start = match.index ?? 0;
+    const end = start + match[0].length;
+    const insideFenced = regions.some((r) => start >= r.start && end <= r.end);
+    if (!insideFenced) {
+      regions.push({ start, end });
+    }
+  }
+
+  regions.sort((a, b) => a.start - b.start);
+  return regions;
+}
+
+export function isInsideCode(pos: number, regions: CodeRegion[]): boolean {
+  return regions.some((r) => pos >= r.start && pos < r.end);
+}
diff --git a/src/shared/text/reasoning-tags.ts b/src/shared/text/reasoning-tags.ts
index 426d0832201..fcf508b5724 100644
--- a/src/shared/text/reasoning-tags.ts
+++ b/src/shared/text/reasoning-tags.ts
@@ -1,3 +1,4 @@
+import { findCodeRegions, isInsideCode } from "./code-regions.js";
 export type ReasoningTagMode = "strict" | "preserve";
 export type ReasoningTagTrim = "none" | "start" | "both";
 
@@ -5,38 +6,6 @@ const QUICK_TAG_RE = /<\s*\/?\s*(?:think(?:ing)?|thought|antthinking|final)\b/i;
 const FINAL_TAG_RE = /<\s*\/?\s*final\b[^<>]*>/gi;
 const THINKING_TAG_RE = /<\s*(\/?)\s*(?:think(?:ing)?|thought|antthinking)\b[^<>]*>/gi;
 
-interface CodeRegion {
-  start: number;
-  end: number;
-}
-
-function findCodeRegions(text: string): CodeRegion[] {
-  const regions: CodeRegion[] = [];
-
-  const fencedRe = /(^|\n)(```|~~~)[^\n]*\n[\s\S]*?(?:\n\2(?:\n|$)|$)/g;
-  for (const match of text.matchAll(fencedRe)) {
-    const start = (match.index ?? 0) + match[1].length;
-    regions.push({ start, end: start + match[0].length - match[1].length });
-  }
-
-  const inlineRe = /`+[^`]+`+/g;
-  for (const match of text.matchAll(inlineRe)) {
-    const start = match.index ?? 0;
-    const end = start + match[0].length;
-    const insideFenced = regions.some((r) => start >= r.start && end <= r.end);
-    if (!insideFenced) {
-      regions.push({ start, end });
-    }
-  }
-
-  regions.sort((a, b) => a.start - b.start);
-  return regions;
-}
-
-function isInsideCode(pos: number, regions: CodeRegion[]): boolean {
-  return regions.some((r) => pos >= r.start && pos < r.end);
-}
-
 function applyTrim(value: string, mode: ReasoningTagTrim): string {
   if (mode === "none") {
     return value;
diff --git a/src/telegram/reasoning-lane-coordinator.test.ts b/src/telegram/reasoning-lane-coordinator.test.ts
index 2dd3a94647f..795efcf8c49 100644
--- a/src/telegram/reasoning-lane-coordinator.test.ts
+++ b/src/telegram/reasoning-lane-coordinator.test.ts
@@ -22,4 +22,8 @@ describe("splitTelegramReasoningText", () => {
       answerText: text,
     });
   });
+
+  it("does not emit partial reasoning tag prefixes", () => {
+    expect(splitTelegramReasoningText("  <thi")).toEqual({});
+  });
 });
diff --git a/src/telegram/reasoning-lane-coordinator.ts b/src/telegram/reasoning-lane-coordinator.ts
index 045ab46b28f..a0207a39c72 100644
--- a/src/telegram/reasoning-lane-coordinator.ts
+++ b/src/telegram/reasoning-lane-coordinator.ts
@@ -1,5 +1,6 @@
 import { formatReasoningMessage } from "../agents/pi-embedded-utils.js";
 import type { ReplyPayload } from "../auto-reply/types.js";
+import { findCodeRegions, isInsideCode } from "../shared/text/code-regions.js";
 import { stripReasoningTagsFromText } from "../shared/text/reasoning-tags.js";
 
 const REASONING_MESSAGE_PREFIX = "Reasoning:\n";
@@ -15,38 +16,6 @@ const REASONING_TAG_PREFIXES = [
 ];
 const THINKING_TAG_RE = /<\s*(\/?)\s*(?:think(?:ing)?|thought|antthinking)\b[^<>]*>/gi;
 
-interface CodeRegion {
-  start: number;
-  end: number;
-}
-
-function findCodeRegions(text: string): CodeRegion[] {
-  const regions: CodeRegion[] = [];
-
-  const fencedRe = /(^|\n)(```|~~~)[^\n]*\n[\s\S]*?(?:\n\2(?:\n|$)|$)/g;
-  for (const match of text.matchAll(fencedRe)) {
-    const start = (match.index ?? 0) + match[1].length;
-    regions.push({ start, end: start + match[0].length - match[1].length });
-  }
-
-  const inlineRe = /`+[^`]+`+/g;
-  for (const match of text.matchAll(inlineRe)) {
-    const start = match.index ?? 0;
-    const end = start + match[0].length;
-    const insideFenced = regions.some((r) => start >= r.start && end <= r.end);
-    if (!insideFenced) {
-      regions.push({ start, end });
-    }
-  }
-
-  regions.sort((a, b) => a.start - b.start);
-  return regions;
-}
-
-function isInsideCode(pos: number, regions: CodeRegion[]): boolean {
-  return regions.some((r) => pos >= r.start && pos < r.end);
-}
-
 function extractThinkingFromTaggedStreamOutsideCode(text: string): string {
   if (!text) {
     return "";