Safer line edits

The edit tool needs an exact text match. The edit_lines tool (hashline) edits by line numbers from the model’s last read, with a hash proving the file has not changed since.

If the hash still matches, the edit applies. If the file drifted, tsforge tries recovery instead of silently writing to the wrong lines.

Always on.

Read format

When the model reads a file with hashline enabled, it sees:

¶src/app.ts#3F2A
1:import { foo } from "./foo";
2:export function main() {}

¶path#HASH is the anchor. HASH is four hex characters from the file contents at read time.

Edit format

Operation	Syntax
Replace lines	replace N..M: then lines prefixed with +
Delete lines	delete N or delete N..M
Insert lines	insert before N: or insert after N:

Line numbers are 1-based. Multiple ops apply bottom-up so line numbers stay stable.

If the hash is stale

Result	Meaning
Hash matches	edit applies
Hash mismatch	tsforge tries a 3-way merge from a snapshot
Merge fails	model must re-read and retry

→ File ops · Big picture