Anthropic / skills/xlsx/SKILL.md
Excel Spreadsheets
A spreadsheet workflow for formula-based workbooks, formatting and recalculation checks. It makes useful distinctions between formulas and cached values, but verification can rewrite the workbook and does not prove the calculations are correct.
Source reviewed · reviewed · Named sources were inspected. No runtime results are established by this label.
01 / Task fit
Where it may help.
These are intended uses indicated by the upstream material. They are not measured outcomes.
- Formula-based workbook drafts with explicit assumptions
- Careful updates to existing spreadsheet templates
What it is
A skill for creating or editing spreadsheet files with Python libraries and a LibreOffice recalculation helper. It tells an agent how to preserve formulas, document assumptions, follow an existing workbook's conventions and check error results. It is not a spreadsheet application or an independent financial validator.
Why you might use it
Use it when the output needs editable formulas rather than a pasted table of calculated numbers. Its guidance is useful for catching missing cached values, accidental formula replacement and the difference between a script that exits successfully and a workbook that has passed meaningful checks.
Put it in context.
Illustrative requests and outputs to review. These examples are separate from the recorded evaluation below.
Build a small capacity-planning workbook
Example request
Use synthetic inputs for five roles: hours available, planned work and a reserve percentage. Request clearly marked input cells, formula-based totals, one example row and a visible assumptions note.
What to look for. A draft workbook with editable inputs and traceable formulas, recalculated and checked against hand-worked examples in an authorized runtime.
Before you rely on it. This example was not executed. A zero-error recalculation can still use the wrong range or assumption; compare expected totals independently.
Update an existing reporting template
Example request
On a copy of a monthly template, identify its designated input cells, insert synthetic current-period values and compare formula cells and external links with the retained original before recalculation.
What to look for. A draft workbook that follows the template's conventions with a clear account of changed cells.
Before you rely on it. This example was not executed. Saving cached-value-only loads can replace formulas, and external workbook links need special handling. Avoid --force unless the loss is understood and approved.
02 / Setup & access
What it asks of your environment.
Requirements
- An agent with local file and shell access in an environment permitted by the proprietary per-skill terms; the adjacent Apache-licensed skills do not extend their license to this folder.
- Python with openpyxl, pandas and markitdown as needed; LibreOffice/soffice for actual formula recalculation. Formula strings alone do not supply cached results.
- Copies of the intended workbook and source values. Macro-enabled files, external links and newer Excel functions require separate compatibility checks; no Excel account is inherently required for the local helpers.
Permissions & data access
- Read and write spreadsheets, formulas, comments, links and embedded workbook metadata. recalc.py rewrites its input file.
- Launch LibreOffice with a temporary profile and install the helper's recalculation macro in that profile. Dependency setup and optional runtime shim paths may invoke additional local tools; no confinement is supplied by the skill itself.
Instructions alone do not enforce a sandbox. The agent host, connected tools and approvals determine what the skill can actually read, change or send.
03 / Things to check
Security concerns & practical limits.
These concerns follow from the reviewed sources. They describe possible exposure or required review; they are not confirmed vulnerabilities.
Review before use
Runtime not run: restrictive per-skill terms
The pinned XLSX license subjects the skill to Anthropic-service agreements and adds restrictions on outside copies, derivatives and redistribution. No XLSX helper was imported or executed here. LibreOffice was also unavailable in this evaluation environment.
Review before use
Recalculation rewrites the workbook
Source review confirms that recalc.py opens a fresh LibreOffice profile, installs a recalculation macro there and saves the workbook in place. Its external-link check refuses one documented loss condition unless --force is supplied; charts and conditional-format references are explicitly outside that check's completeness claim.
Review before use
An error-free process exit is not an error-free workbook
The script exits nonzero only when the JSON contains an error key. A result with status errors_found exits zero. Read status and total_errors explicitly, and validate the formulas against expected business results.
Review before use
Error scanning also matches ordinary text
The source scanner searches for error tokens inside every string cell without checking Excel's cell error type. Text that discusses an error such as #REF! can be counted as a formula error. This is a source trace, not a workbook runtime reproduction.
Limits and nuances
- Runtime not run because of the per-skill license boundary; LibreOffice was unavailable too. Source review does not establish successful recalculation or document safety.
- No Excel/LibreOffice compatibility, macros, external-link recovery, chart preservation, numerical correctness or real business model was tested.
04 / Review record
What we checked. What’s still open.
Recorded review scope
- Manual review of formula/cache guidance, per-skill terms, external-link checks, profile handling, error scanning and exit-code behavior. Runtime not run.
- Pinned entrypoint, per-skill license and each file named in the report source manifest
Not tested or established
- Runtime not run because of the per-skill license boundary; LibreOffice was unavailable too. Source review does not establish successful recalculation or document safety.
- No Excel/LibreOffice compatibility, macros, external-link recovery, chart preservation, numerical correctness or real business model was tested.
- One bounded pass at one pinned revision; no model-effectiveness baseline, repeated trials, security certification or assurance about future versions.
- No private files, credentials, authenticated accounts, paid requests or real customer workflows. Transitive dependencies and current vulnerability advisories were not audited.
- Review date
- Source revision
dbd4588f9e1033efb41dad4bef2f7947c8993d44- Our relationship
- Explored. Investigated through the recorded review. No use or replication is claimed.
Upstream content can change after review. A repository revision identifies source scope; it does not prove that every script, dependency or runtime behavior was tested. How freshness is handled.
Recorded evaluation / Source review
Results with their limits attached.
Runtime not run because of the per-skill license boundary; LibreOffice was unavailable too. Six manual source-review expectations: five met, with an error-scanning concern retained. No workbook was recalculated.
- Passed
- 5
- Failed
- 1
- Total recorded
- 6
These counts refer to the cases in this report. They are not a benchmark against other skills. A source review does not establish runtime behavior.
Read the evidence reportThe report provides the case definitions, observations and baseline scope. Missing baselines or untested behaviors remain limitations.
Recorded environment
- Manual review of pinned public source; no upstream code imported or executed
Recorded commands (1)
Commands document this evaluation. They are not setup instructions for your environment.
Read pinned entrypoint, per-skill license and named helper control flow; record findings without executing the upstream skill.Findings from this evaluation
Needs attention
Runtime not run: restrictive per-skill terms
The pinned XLSX license subjects the skill to Anthropic-service agreements and adds restrictions on outside copies, derivatives and redistribution. No XLSX helper was imported or executed here. LibreOffice was also unavailable in this evaluation environment.
Needs attention
Recalculation rewrites the workbook
Source review confirms that recalc.py opens a fresh LibreOffice profile, installs a recalculation macro there and saves the workbook in place. Its external-link check refuses one documented loss condition unless --force is supplied; charts and conditional-format references are explicitly outside that check's completeness claim.
Needs attention
An error-free process exit is not an error-free workbook
The script exits nonzero only when the JSON contains an error key. A result with status errors_found exits zero. Read status and total_errors explicitly, and validate the formulas against expected business results.
Needs attention
Error scanning also matches ordinary text
The source scanner searches for error tokens inside every string cell without checking Excel's cell error type. Text that discusses an error such as #REF! can be counted as a formula error. This is a source trace, not a workbook runtime reproduction.
Evaluation limitations
- Runtime not run because of the per-skill license boundary; LibreOffice was unavailable too. Source review does not establish successful recalculation or document safety.
- No Excel/LibreOffice compatibility, macros, external-link recovery, chart preservation, numerical correctness or real business model was tested.
- One bounded pass at one pinned revision; no model-effectiveness baseline, repeated trials, security certification or assurance about future versions.
- No private files, credentials, authenticated accounts, paid requests or real customer workflows. Transitive dependencies and current vulnerability advisories were not audited.
05 / Reuse & discovery
License, attribution & popularity.
Proprietary / service terms
The separate per-skill license was read at this revision. It ties use to Anthropic-service terms and adds restrictions on copying, derivatives and redistribution; this source review does not grant permission to install or reuse it.
Why it is in this collection
Selected from a widely followed repository and dated skills.sh directory observations. Installs are rounded directory displays, not independently verified users or evidence of quality, safety or growth.
182,031 repository stars
- Scope
- Entire anthropics/skills repository, not this individual skill
- Observed
- Time window
- Snapshot observed 2026-10-19
Popularity and inclusion do not establish quality, compatibility or security. Counts belong to their named metric and date; they are not a current ranking.
Dated discovery signal
Discovery snapshots.
184,300 skill installs on skills.sh · Page labels this Installs without stating a time window
Observed . Scope: Individual xlsx directory listing; rounded display.
Selection snapshot; displayed K value converted to an approximate integer. No rate, rank or measured trend is inferred.
Snapshot source ↗06 / Follow the evidence
Go to the original.
- Pinned skill instructions github.com
- Per-skill license github.com
- recalc.py inspected source github.com
- soffice.py inspected source github.com
- Dated directory interest signal www.skills.sh
IonBin’s source notes are independent assessments. Upstream authors retain their work and attribution. This page does not install or execute the skill.