Copy src to dst, then splice new_bytes_b64 at offset.

This is the on-disk patch primitive. The original bytes at src are never modified; the patch is written to a copy at dst. The function returns both the pre-patch and post-patch SHA-256 so the analyst can record the patch's net effect in the report.

Args: src: source file (the original; never modified) dst: destination file (created or overwritten with the patched copy) offset: byte offset into dst at which to write (0-based) new_bytes_b64: base64-encoded bytes to splice in confirm_legal: free-text justification (the audit trail; the server does not enforce policy)

Returns::

{
  "src": "...",
  "dst": "...",
  "src_sha256": "<original>",
  "dst_sha256": "<patched>",
  "src_size": N,
  "dst_size": N,
  "offset": N,
  "patched_bytes": M,
  "confirm_legal": "...",
}

Override-scope contract: this tool is gated behind the run's policy override (see override-scope.md of the active run). The override authorizes on-disk patches only inside Output/<run-id>/patches/; the confirm_legal text must reference the override file and the rationale.

Return server status + version. Always status: OK — re-patch has no external system dependencies (pure Python stdlib + mcp / pydantic).

Copy original back to restore_target, optionally verifying the original's SHA-256 against expected_sha256 first.

This is the rollback primitive. The function:

1. Computes the SHA-256 of original.

2. If expected_sha256 is non-empty, verifies the computed hash matches (refuses to proceed otherwise).

3. Copies original to restore_target (overwriting).

Args: original: file whose bytes are the canonical "original" (typically the source the patch was applied from) restore_target: file to write the original bytes to (typically the patched copy) expected_sha256: optional hex-encoded SHA-256 to verify original against confirm_legal: free-text justification (audit trail)

Returns::

{
  "original": "...",
  "restore_target": "...",
  "original_sha256": "<hash>",
  "expected_sha256": "<hash>" or null,
  "verified": bool,
  "confirm_legal": "...",
}

Compute the SHA-256 manifest of path.

Args: path: file to hash

Returns::

{
  "path": "...",
  "size": N,
  "sha256": "<64 hex chars>",
}

Use this to record the canonical SHA-256 of the original binary before any patch is applied. The hash is the rollback key: restore_original(original, target, expected_sha256=...) will refuse to proceed if the original's hash has drifted.