apply-patch

apply_patch Tool Instructions

Use apply_patch to create, update, move, rename, or delete text files through a structured, reviewable patch.

Tool contract

• Input type: FREEFORM.
• Pass exactly one raw patch string.
• Do not wrap the patch in JSON.
• Do not wrap the patch in Markdown fences.
• Do not include commentary before or after the patch.
• Do not invoke apply_patch in parallel with another tool.
• Use LF (\n) line endings in the patch input.

A patch must begin with *** Begin Patch and end with *** End Patch.

Formal grammar

The following grammar uses Lark syntax and assumes a contextual lexer. Whitespace is significant and must not be globally ignored.

start: begin_patch operation+ end_patch

begin_patch: "*** Begin Patch" LF
end_patch: "*** End Patch" LF?

?operation: add_file
          | delete_file
          | update_file

// Create a non-empty text file.
// Every content line, including an empty content line, begins with "+".
add_file: "*** Add File: " path LF add_line+
add_line: "+" line_text LF

// Delete an existing file.
// A delete operation has no body.
delete_file: "*** Delete File: " path LF

// Update an existing file, move it, or do both.
// An update must contain a move clause, a change block, or both.
update_file: "*** Update File: " path LF update_body

?update_body: move_clause change_block?
            | change_block

// Move or rename the updated file.
move_clause: "*** Move to: " path LF

// Apply one or more contextual or changed lines.
// The optional EOF marker must be the final item in the block.
change_block: change_item+ eof_marker?

?change_item: section_header
            | change_line

// A section header is a locator and is not written to the file.
section_header: "@@" LF
              | "@@ " nonempty_text LF

// " " means context, "-" means deletion, and "+" means insertion.
change_line: CHANGE_PREFIX line_text LF

// Assert that the preceding change is anchored at the end of the file.
eof_marker: "*** End of File" LF

path: nonempty_text
line_text: NONEMPTY_TEXT?
nonempty_text: NONEMPTY_TEXT

CHANGE_PREFIX: "+" | "-" | " "
NONEMPTY_TEXT: /[^\r\n]+/
LF: "\n"