[BUG] Edit tool writes hash prefix into file content

[ouyangxin1981]

Bug Description

The Edit tool occasionally writes hash prefix markers into the actual file content instead of just using them as internal line references.

Example of corrupted output:

#KW|'use client';
#KM|
#XW|import { useEffect, useRef, useState } from 'react';

Expected output:

'use client';

import { useEffect, useRef, useState } from 'react';

Root Cause

The Edit tool uses internal line references in the format {line_number}#{hash_id} where hash_id is from the set ZPMQVRWSNKTXJBYH. There appears to be a bug where these hash IDs are occasionally written into the actual file content instead of being used purely as internal references.

Impact

• TypeScript/JavaScript files become syntactically invalid
• Build failures
• Requires manual file rewrite to fix

Workaround

Use Write tool (full file rewrite) instead of Edit tool.

Environment

• OpenCode version: Latest
• OS: Linux

Steps to Reproduce

1. Use Edit tool to make changes to a TypeScript file
2. Observe that hash prefix like #KW|, #KM|, #XW| appear at the start of lines

Frequency

This has occurred multiple times across different files in this project.