Before sharing an AI-prepared CSV for spreadsheet use, check that source text remains text when the recipient imports it. A file can have the right columns, valid quoting and accurate row counts while a field is interpreted as a formula. The receiving application and import settings are part of the handoff.
This matters when an assistant turns tickets, survey comments, supplier records or extracted documents into a downloadable table. The assistant may faithfully carry a source value into the export. Faithful copying does not establish that opening the result will preserve the value’s intended meaning.
The practical task is to define which fields are text, which contain numbers and where calculations are deliberately allowed. This guide proposes an export brief and a fictional support-report example. We have not executed these examples in Excel or Calc, tested a model or independently evaluated an export product.
Separate CSV structure from spreadsheet interpretation
CSV stores delimited fields. Quotes can keep a comma inside one field and allow embedded quotation marks to be represented correctly. They do not provide a universal declaration that a receiving spreadsheet must treat the field as literal text.
OWASP’s CSV Injection guidance describes how untrusted input in exports can become spreadsheet formulas. It identifies formula-initiating characters and warns that delimiters, quotes, application differences and save/reopen behavior matter. Its guidance explicitly rejects a universal sanitization strategy for every spreadsheet and downstream consumer.
The immediate business question is therefore broader than “did AI produce a valid CSV?” Ask what the file is for and how it will be consumed. A machine ingestion pipeline expecting exact source strings has different needs from a file intended for staff to view in a spreadsheet. A transformation useful for one route can alter data needed by the other.
This is distinct from checking whether an intended calculation is correct. Our AI spreadsheet formula guide covers that task. Here the concern is a field that was never meant to be a calculation at all.
Research shows why the export boundary matters
In the August 2025 WOOT paper Comma Separated Vulnerabilities, Manuel Karl and colleagues study flows from user-controlled input into CSV exports in open-source Java applications. Their work combines static analysis with manual assessment of realistic attack conditions. It also examines spreadsheet behavior and CSV libraries.
The research concerns selected applications, frameworks and software versions, with limitations in the flows its analysis can detect. It is not a benchmark of AI assistants or an estimate of how often today’s AI-generated exports are unsafe. Its relevant lesson is that data can cross a trust boundary through a routine export, even when the exporting application is familiar to its recipient.
George Mauer’s October 2017 practitioner article illustrates that familiar workflow using a time-tracking export and quoted formula-like content. It is historical explanation, not evidence that old exploit behavior remains unchanged in current spreadsheet versions.
Adding AI to the workflow does not create this entire problem, and asking the assistant to copy values accurately does not resolve it. The export process still needs a deliberate decision about how source data may be interpreted.
Define a fictional support-report contract
Imagine a fictional operations team asking an assistant to consolidate support records. The export contains a ticket identifier, customer-supplied subject and signed adjustment amount. The subject is source text. The adjustment is a validated number. The report does not require any generated formulas.
The team can specify the intended meaning before choosing the delivery format:
| Field | Intended meaning | Handoff requirement |
|---|---|---|
| Ticket ID | Text identifier, including leading zeros | Preserve the complete identifier |
| Subject | Literal source text supplied by another party | Display as text; do not evaluate it |
| Adjustment | Validated signed decimal amount | Preserve the number and sign under the agreed locale |
| Review status | One of the team’s defined labels | Flag unsupported or missing labels for review |
Consider the harmless illustrative subject =1+1. The required subject is those four characters. If an import evaluates it and displays 2, the field has changed meaning. This is a proposed diagnostic example, not an observed result from our testing.
A subject containing a comma, a double quote or an embedded line break tests another requirement: the value must remain in one intended field. That structural check is separate from whether the field becomes a formula. Both can matter in the same export.
Also include ordinary cases that must remain useful. A ticket ID such as 000742 must not silently lose zeros. A numeric adjustment of -12.50 must remain a valid negative amount rather than being rejected solely because its first character is a minus sign. Field expectations help avoid treating every column as interchangeable text.
Choose a delivery route that matches the consumer
For an automated recipient, agree a schema, encoding and parsing rules. Preserve the original strings and validate numeric columns deliberately. Avoid silently adding characters to source fields simply to make a spreadsheet viewing route more convenient.
For spreadsheet viewing, consider a controlled import procedure or a workbook exporter that explicitly writes source fields as string cells and confines formulas to intended locations. A workbook extension alone is insufficient: the writer still has to choose the correct cell types, and the saved artifact needs inspection.
LibreOffice’s current Text Import help, displaying version 26.8 when accessed, documents options for treating quoted fields as text, selecting a text column type and deciding whether expressions beginning with an equals sign are evaluated. It also explains that saved import settings may be applied automatically. These are documented product controls, not evidence that your recipients use those settings or that every spreadsheet behaves the same way.
Record the route in the export brief. “CSV imported through the agreed text-import procedure” is a more specific acceptance condition than “opens in a spreadsheet.” If the workflow depends on each recipient remembering a particular option, the team should decide whether it can support that dependency before distributing the file widely.
Test the artifact through its actual handoff
Use a small fictional fixture before handling real business data. Include literal formula-like text, punctuation, line breaks, leading-zero identifiers and legitimate negative numbers. Keep the fixture harmless: no external requests, system commands or links to live resources are needed to test the basic interpretation boundary.
Inspect the saved output first with a CSV parser or the workbook’s structural tools. Check field boundaries, row counts and values against the fixture. Then exercise the intended receiving application and import route in an appropriate test environment. Inspect both the displayed result and the underlying cell type or formula state.
If the real process includes editing, saving and reopening, include those steps. A first successful display is not evidence about every later conversion. Record the application version, locale, import options and file format used at each stage so a reviewer knows what the result establishes.
OWASP also notes that a tab-based mitigation described for Excel changes the underlying data and may affect programmatic consumers. Treat that as a reason to evaluate the full workflow, rather than blindly applying a prefix everywhere. If a viewing copy transforms values, label that copy and retain an access-controlled original for legitimate reconciliation.
Give AI a bounded role in export preparation
Ask the assistant to identify source-controlled text fields, propose a field contract and flag any deliberate calculations. Have it explain whether its chosen exporter writes strings or infers formulas. Require the actual checks run, including any receiving applications that remain untested.
For a recurring workflow, put serialization and field validation into maintained code using a suitable library. Review that code against the export contract. A fluent assurance that the CSV was “escaped” does not explain which interpretation risks were addressed or which consumer was tested.
Keep the final acceptance decision concrete: the intended fields survive, text remains text, permitted numbers retain their meaning and any viewing transformations are documented. If the receiving route is unknown, report that limitation and agree a supported route before claiming the export is ready for spreadsheet use. The useful result is a handoff whose behavior the team can explain and verify.