“Because their exporter is legacy,” said the Atwood contact. “We didn’t want to risk disrupting your live service. We routed the correction through our maintenance mirror. We thought it was a temporary workaround.”

“Patchwork.”

“Why patchwork?” Tom asked.

“Get me the logs,” she said. She had to know who had tried to write to the portal at 02:37.

Mara opened her laptop and tried to breathe logically. The spreadsheet from Atwood Logistics, the one with new scope-3 figures and a promised emissions methodology, had been overdue. She’d expected it this morning. She pulled the cached version of the draft she’d worked on last night and ran the checks she always did: row counts, column headers, checksum. Everything matched, but the missing final worksheet nagged at her.

Mara’s mind leapt. The Atwood file. The mismatched hash. She remembered a message from their supplier’s portal manager, a casual line in an email two days ago: “Upgraded our exporter — you might see new metadata.” No further explanation. She dug into the partial payload captured by the portal: a blob with an extra header, a field labelled “provenance” filled with a string of base64 characters.