diff --git a/src/tools/hashline-edit/constants.ts b/src/tools/hashline-edit/constants.ts
index 4ecf66c46..2eac4d9c2 100644
--- a/src/tools/hashline-edit/constants.ts
+++ b/src/tools/hashline-edit/constants.ts
@@ -7,5 +7,4 @@ export const HASHLINE_DICT = Array.from({ length: 256 }, (_, i) => {
 })
 
 export const HASHLINE_REF_PATTERN = /^([0-9]+)#([ZPMQVRWSNKTXJBYH]{2})$/
-export const HASHLINE_OUTPUT_PATTERN = /^([0-9]+)#([ZPMQVRWSNKTXJBYH]{2}):(.*)$/
-export const HASHLINE_LEGACY_REF_PATTERN = /^([0-9]+):([0-9a-fA-F]{2,})$/
+export const HASHLINE_OUTPUT_PATTERN = /^([0-9]+)#([ZPMQVRWSNKTXJBYH]{2})\|(.*)$/
diff --git a/src/tools/hashline-edit/edit-operation-primitives.ts b/src/tools/hashline-edit/edit-operation-primitives.ts
index 43904011c..cd93e923d 100644
--- a/src/tools/hashline-edit/edit-operation-primitives.ts
+++ b/src/tools/hashline-edit/edit-operation-primitives.ts
@@ -80,7 +80,7 @@ export function applyInsertAfter(
   const result = [...lines]
   const newLines = stripInsertAnchorEcho(lines[line - 1], toNewLines(text))
   if (newLines.length === 0) {
-    throw new Error(`insert_after requires non-empty text for ${anchor}`)
+    throw new Error(`append (anchored) requires non-empty text for ${anchor}`)
   }
   result.splice(line, 0, ...newLines)
   return result
@@ -97,38 +97,12 @@ export function applyInsertBefore(
   const result = [...lines]
   const newLines = stripInsertBeforeEcho(lines[line - 1], toNewLines(text))
   if (newLines.length === 0) {
-    throw new Error(`insert_before requires non-empty text for ${anchor}`)
+    throw new Error(`prepend (anchored) requires non-empty text for ${anchor}`)
   }
   result.splice(line - 1, 0, ...newLines)
   return result
 }
 
-export function applyInsertBetween(
-  lines: string[],
-  afterAnchor: string,
-  beforeAnchor: string,
-  text: string | string[],
-  options?: EditApplyOptions
-): string[] {
-  if (shouldValidate(options)) {
-    validateLineRef(lines, afterAnchor)
-    validateLineRef(lines, beforeAnchor)
-  }
-  const { line: afterLine } = parseLineRef(afterAnchor)
-  const { line: beforeLine } = parseLineRef(beforeAnchor)
-  if (beforeLine <= afterLine) {
-    throw new Error(`insert_between requires after_line (${afterLine}) < before_line (${beforeLine})`)
-  }
-
-  const result = [...lines]
-  const newLines = stripInsertBoundaryEcho(lines[afterLine - 1], lines[beforeLine - 1], toNewLines(text))
-  if (newLines.length === 0) {
-    throw new Error(`insert_between requires non-empty text for ${afterAnchor}..${beforeAnchor}`)
-  }
-  result.splice(beforeLine - 1, 0, ...newLines)
-  return result
-}
-
 export function applyAppend(lines: string[], text: string | string[]): string[] {
   const normalized = toNewLines(text)
   if (normalized.length === 0) {
diff --git a/src/tools/hashline-edit/edit-operations.test.ts b/src/tools/hashline-edit/edit-operations.test.ts
index eb0adbaf0..1940b9e46 100644
--- a/src/tools/hashline-edit/edit-operations.test.ts
+++ b/src/tools/hashline-edit/edit-operations.test.ts
@@ -1,6 +1,6 @@
 import { describe, expect, it } from "bun:test"
-import { applyHashlineEdits, applyInsertAfter, applyReplaceLines, applySetLine } from "./edit-operations"
-import { applyAppend, applyInsertBetween, applyPrepend } from "./edit-operation-primitives"
+import { applyHashlineEdits } from "./edit-operations"
+import { applyAppend, applyInsertAfter, applyPrepend, applyReplaceLines, applySetLine } from "./edit-operation-primitives"
 import { computeLineHash } from "./hash-computation"
 import type { HashlineEdit } from "./types"
 
@@ -56,16 +56,6 @@ describe("hashline edit operations", () => {
     expect(result).toEqual("line 1\nbefore 2\nline 2\nline 3")
   })
 
-  it("applies insert_between with dual anchors", () => {
-    //#given
-    const lines = ["line 1", "line 2", "line 3"]
-
-    //#when
-    const result = applyInsertBetween(lines, anchorFor(lines, 1), anchorFor(lines, 2), ["between"]).join("\n")
-
-    //#then
-    expect(result).toEqual("line 1\nbetween\nline 2\nline 3")
-  })
 
   it("throws when insert_after receives empty text array", () => {
     //#given
@@ -85,13 +75,6 @@ describe("hashline edit operations", () => {
     ).toThrow(/non-empty/i)
   })
 
-  it("throws when insert_between receives empty text array", () => {
-    //#given
-    const lines = ["line 1", "line 2"]
-
-    //#when / #then
-    expect(() => applyInsertBetween(lines, anchorFor(lines, 1), anchorFor(lines, 2), [])).toThrow(/non-empty/i)
-  })
 
   it("applies mixed edits in one pass", () => {
     //#given
@@ -215,15 +198,6 @@ describe("hashline edit operations", () => {
     expect(result).toEqual(["before", "new 1", "new 2", "after"])
   })
 
-  it("throws when insert_between payload contains only boundary echoes", () => {
-    //#given
-    const lines = ["line 1", "line 2", "line 3"]
-
-    //#when / #then
-    expect(() => applyInsertBetween(lines, anchorFor(lines, 1), anchorFor(lines, 2), ["line 1", "line 2"])).toThrow(
-      /non-empty/i
-    )
-  })
 
   it("restores indentation for first replace_lines entry", () => {
     //#given
diff --git a/src/tools/hashline-edit/edit-operations.ts b/src/tools/hashline-edit/edit-operations.ts
index 8558b51db..fae662d15 100644
--- a/src/tools/hashline-edit/edit-operations.ts
+++ b/src/tools/hashline-edit/edit-operations.ts
@@ -88,9 +88,3 @@ export function applyHashlineEdits(content: string, edits: HashlineEdit[]): stri
   return applyHashlineEditsWithReport(content, edits).content
 }
 
-export {
-  applySetLine,
-  applyReplaceLines,
-  applyInsertAfter,
-  applyInsertBefore,
-} from "./edit-operation-primitives"
diff --git a/src/tools/hashline-edit/index.ts b/src/tools/hashline-edit/index.ts
index 97a0ba7b2..b38d63d35 100644
--- a/src/tools/hashline-edit/index.ts
+++ b/src/tools/hashline-edit/index.ts
@@ -16,9 +16,5 @@ export type {
 export { NIBBLE_STR, HASHLINE_DICT, HASHLINE_REF_PATTERN, HASHLINE_OUTPUT_PATTERN } from "./constants"
 export {
   applyHashlineEdits,
-  applyInsertAfter,
-  applyInsertBefore,
-  applyReplaceLines,
-  applySetLine,
 } from "./edit-operations"
 export { createHashlineEditTool } from "./tools"
diff --git a/src/tools/hashline-edit/validation.test.ts b/src/tools/hashline-edit/validation.test.ts
index fc401cbf9..cf2457ab3 100644
--- a/src/tools/hashline-edit/validation.test.ts
+++ b/src/tools/hashline-edit/validation.test.ts
@@ -61,46 +61,3 @@ describe("validateLineRef", () => {
       .toThrow(/>>>\s+2#[ZPMQVRWSNKTXJBYH]{2}\|two/)
   })
 })
-
-describe("legacy LINE:HEX backward compatibility", () => {
-  it("parses legacy LINE:HEX ref", () => {
-    //#given
-    const ref = "42:ab"
-
-    //#when
-    const result = parseLineRef(ref)
-
-    //#then
-    expect(result).toEqual({ line: 42, hash: "ab" })
-  })
-
-  it("parses legacy LINE:HEX ref with uppercase hex", () => {
-    //#given
-    const ref = "10:FF"
-
-    //#when
-    const result = parseLineRef(ref)
-
-    //#then
-    expect(result).toEqual({ line: 10, hash: "FF" })
-  })
-
-  it("legacy ref fails validation with hash mismatch, not parse error", () => {
-    //#given
-    const lines = ["function hello() {"]
-
-    //#when / #then
-    expect(() => validateLineRef(lines, "1:ab")).toThrow(/>>>\s+1#[ZPMQVRWSNKTXJBYH]{2}\|/)
-  })
-
-  it("extracts legacy ref from content with markers", () => {
-    //#given
-    const ref = ">>> 42:ab|const x = 1"
-
-    //#when
-    const result = parseLineRef(ref)
-
-    //#then
-    expect(result).toEqual({ line: 42, hash: "ab" })
-  })
-})
diff --git a/src/tools/hashline-edit/validation.ts b/src/tools/hashline-edit/validation.ts
index f81ccbaa4..72a332866 100644
--- a/src/tools/hashline-edit/validation.ts
+++ b/src/tools/hashline-edit/validation.ts
@@ -1,5 +1,5 @@
 import { computeLineHash } from "./hash-computation"
-import { HASHLINE_REF_PATTERN, HASHLINE_LEGACY_REF_PATTERN } from "./constants"
+import { HASHLINE_REF_PATTERN } from "./constants"
 
 export interface LineRef {
   line: number
@@ -13,16 +13,13 @@ interface HashMismatch {
 
 const MISMATCH_CONTEXT = 2
 
-const LINE_REF_EXTRACT_PATTERN = /([0-9]+#[ZPMQVRWSNKTXJBYH]{2}|[0-9]+:[0-9a-fA-F]{2,})/
+const LINE_REF_EXTRACT_PATTERN = /([0-9]+#[ZPMQVRWSNKTXJBYH]{2})/
 
 function normalizeLineRef(ref: string): string {
   const trimmed = ref.trim()
   if (HASHLINE_REF_PATTERN.test(trimmed)) {
     return trimmed
   }
-  if (HASHLINE_LEGACY_REF_PATTERN.test(trimmed)) {
-    return trimmed
-  }
 
   const extracted = trimmed.match(LINE_REF_EXTRACT_PATTERN)
   if (extracted) {
@@ -41,13 +38,6 @@ export function parseLineRef(ref: string): LineRef {
       hash: match[2],
     }
   }
-  const legacyMatch = normalized.match(HASHLINE_LEGACY_REF_PATTERN)
-  if (legacyMatch) {
-    return {
-      line: Number.parseInt(legacyMatch[1], 10),
-      hash: legacyMatch[2],
-    }
-  }
   throw new Error(
     `Invalid line reference format: "${ref}". Expected format: "LINE#ID" (e.g., "42#VK")`
   )