xlsx-input-code-output-canary

name	xlsx-input-code-output-canary
description	Classifies XLS/XLSX workbooks before extraction and requires a traceable input data or logic contract, code artifact, and verified output artifact for a ten-file canary. Use when spreadsheet files may contain formulas, named ranges, charts, cached values, protection, or mixed data and calculation logic.
license	CC-BY-4.0
compatibility	Requires Python 3.10+, uv, openpyxl, python-calamine, and cache-only access to online canary workbooks when fetch verification is requested
metadata	{"version":"1.0","enforcement_level":"L2","incident_refs":"blind-table-dump,cached-value-as-proof,raw-workbook-commit,license-uncertainty","params":"mode:enum(manifest-check,fetch,inventory,classify,self-test) | cache:external-path"}

xlsx-input-code-output-canary

This skill prevents blind spreadsheet extraction. A workbook is not just a table: it may contain input cells, formulas, named ranges, charts, stale cached values, protection, or unsupported logic. The canary must prove the whole loop:

source manifest -> cache/hash check -> inventory -> classification -> code artifact -> output proof

Trigger

Use this before broad XLS/XLSX extraction, especially for llm-wiki issue #3 or any corpus where spreadsheets are being treated as machine-readable high-yield files.

Preconditions

1. A user-approved issue plan authorizes this workflow.
2. Raw workbook bytes are not committed. Online samples stay as URLs and hashes; fetched bytes go only to an external local cache.
3. Licenses are recorded before a source is used. GPL/EUPL/proprietary projects remain reference-only unless explicitly approved.
4. Formula cached values are evidence only. They are never accepted as verified calculations.

Steps

1. Validate the manifest.

   uv run skills/xlsx-input-code-output-canary/resources/xlsx_canary.py manifest-check \
     --manifest skills/xlsx-input-code-output-canary/resources/canary_manifest.json
   

   The manifest must have exactly five simple and five complex workbooks, with URL, license, byte count, sha256, purpose, and expected flags for each source.
2. Run the offline self-test before online fetch.

   uv run skills/xlsx-input-code-output-canary/resources/xlsx_canary.py self-test
   

   The generated fixtures prove the basic data, calculation, and guarded paths without network or raw committed workbooks.
3. Fetch only when needed, into an external cache.

   uv run skills/xlsx-input-code-output-canary/resources/xlsx_canary.py fetch \
     --manifest skills/xlsx-input-code-output-canary/resources/canary_manifest.json \
     --cache-dir ~/.cache/raw-to-knowledge-playbook/xlsx-canary
   

   The helper refuses repo-local caches unless explicitly overridden for a throwaway local run.
4. Inventory each workbook.

   uv run skills/xlsx-input-code-output-canary/resources/xlsx_canary.py inventory \
     --workbook ~/.cache/raw-to-knowledge-playbook/xlsx-canary/S1-base-xlsx-base.xlsx \
     --source-id S1-base-xlsx
   

   Inventory records sheet names, formula cells and cached values, named ranges, tables, merged ranges, charts, protection flags, parser versions, and sha256.
5. Classify from inventory.

   uv run skills/xlsx-input-code-output-canary/resources/xlsx_canary.py classify \
     --inventory /path/to/inventory.json
   

   Use only the closed classes: data, calculation, mixed, guarded, unsupported.
6. Require the triplet before promotion.
   • data: input schema/ranges -> parser or schema code -> normalized tables.
   • calculation: input cells/formula graph -> evaluator or ported code -> recomputed output proof.
   • mixed: separate data and formula paths before output proof.
   • guarded or unsupported: explicit deferral artifact with reason.

Verification

• uv run skills/validate_skill.py --strict passes.
• manifest-check passes for resources/canary_manifest.json.
• self-test passes and proves data, calculation, and guarded paths.
• No raw .xls, .xlsx, .xlsm, or .xlsb bytes are committed.
• Every canary source has URL, license note, byte count, and sha256.
• Formula workbooks are never marked verified from cached values alone.

Cleanup

• Remove any temporary inventory/output files produced outside committed paths.
• Keep fetched workbooks in an external cache or delete them after the canary run.
• Do not add cache directories or raw workbook bytes to git.

Incident appendix

Rule	Why
No blind table dump	Spreadsheet knowledge can be formula logic, not visible cells
Cached value is not proof	Stale cached results can look authoritative while formulas are wrong
Cache-only raw files	Committing third-party workbooks creates license and privacy residue
Closed classification vocabulary	Agents otherwise invent reassuring statuses that do not gate scale-up
License before source use	Fixture convenience must not override redistribution constraints