diff --git a/src/tools/hashline-edit/edit-operations.ts b/src/tools/hashline-edit/edit-operations.ts
index a91863ee..7a6340db 100644
--- a/src/tools/hashline-edit/edit-operations.ts
+++ b/src/tools/hashline-edit/edit-operations.ts
@@ -62,7 +62,7 @@ function getEditLineNumber(edit: HashlineEdit): number {
     case "insert_after":
       return parseLineRef(edit.line).line
     case "replace":
-      return Number.POSITIVE_INFINITY
+      return Number.NEGATIVE_INFINITY
     default:
       return Number.POSITIVE_INFINITY
   }
diff --git a/src/tools/hashline-edit/tools.ts b/src/tools/hashline-edit/tools.ts
index a4bfab18..8c970582 100644
--- a/src/tools/hashline-edit/tools.ts
+++ b/src/tools/hashline-edit/tools.ts
@@ -41,7 +41,7 @@ export function createHashlineEditTool(): ToolDefinition {
 LINE:HASH FORMAT:
 Each line reference must be in "LINE:HASH" format where:
 - LINE: 1-based line number
-- HASH: First 2 characters of SHA-256 hash of line content (computed with computeLineHash)
+- HASH: First 2 characters of xxHash32 hash of line content (computed with computeLineHash)
 - Example: "5:a3|const x = 1" means line 5 with hash "a3"
 
 GETTING HASHES: