Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add sbroenne/mcp-server-excel --skill excel-mcpgit clone --depth 1 https://github.com/sbroenne/mcp-server-excelWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/sbroenne/mcp-server-excel/excel-mcp)<a href="https://agentmods.dev/skills/sbroenne/mcp-server-excel/excel-mcp"><img src="https://agentmods.dev/badge/skills/sbroenne/mcp-server-excel/excel-mcp.svg" alt="Measured on agentmods" height="20"></a>- Socket pass
- Snyk warn
- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00106 | $0.02065 |
| Opus 5 | $0.00053 | $0.01033 |
| Sonnet 5 | $0.00021 | $0.00413 |
| Haiku 4.5 | $0.00011 | $0.00206 |
Grade A, and why
excel-mcp scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 202 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Excel MCP Server Skill
Provides 326 Excel operations via Model Context Protocol. The MCP Server hosts the ExcelMCP Service in-process and calls it directly for low-latency Excel automation. Tools are auto-discovered - this documents quirks, workflows, and gotchas.
Workflow Checklist
| Step | Tool | Action | When |
|---|---|---|---|
| 1. Open file | file |
open or create |
Always first |
| 2. Create sheets | worksheet |
create, rename |
If needed |
| 3. Write data | range |
set-values |
Always (2D arrays) |
| 4. Format | range |
set-number-format |
After writing |
| 5. Structure | table |
create |
Convert data to tables |
| 6. Save & close | file |
close with save: true |
Always last |
Preconditions
- Windows host with Microsoft Excel installed (2016+)
- Use full Windows paths:
C:\Users\Name\Documents\Report.xlsx - Excel files must not be open in another Excel instance
Calculation Mode Workflow (Batch Performance)
Use calculation_mode for bulk write performance optimization. When writing many values or formulas, disable auto-recalc to avoid recalculating after every cell:
1. calculation_mode(action: 'set-mode', mode: 'manual') → Disable auto-recalc
2. Perform all writes (range set-values, set-formulas)
3. calculation_mode(action: 'calculate', scope: 'workbook') → Recalculate once
4. calculation_mode(action: 'set-mode', mode: 'automatic') → Restore default
Note: You do NOT need manual mode to read formulas - range get-formulas returns formula text regardless of calculation mode.
CRITICAL: Execution Rules (MUST FOLLOW)
Rule 1: NEVER Ask Clarifying Questions
STOP. If you're about to ask "Which file?", "What table?", "Where should I put this?" - DON'T.
| Bad (Asking) | Good (Discovering) |
|---|---|
| "Which Excel file should I use?" | file(list) → use the open session |
| "What's the table name?" | table(list) → discover tables |
| "Which sheet has the data?" | worksheet(list) → check all sheets |
| "Should I create a PivotTable?" | YES - create it on a new sheet |
What ships with it
27 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- README.md 2.6 KB
- references/analysis.md 2.0 KB
- references/anti-patterns.md 12 KB
- references/behavioral-rules.md 14 KB
- references/calculation.md 3.0 KB
- references/chart.md 7.7 KB
- references/claude-desktop.md 2.4 KB
- references/conditionalformat.md 8.2 KB
- references/dashboard.md 5.1 KB
- references/datamodel.md 11 KB
- references/dmv-reference.md 2.5 KB
- references/drawing.md 2.0 KB
- references/excel_agent_mode.md 5.7 KB
- references/gotchas.md 6.8 KB
- references/m-code-syntax.md 975 B
- references/pivottable.md 7.2 KB
- references/powerquery.md 8.7 KB
- references/querytable.md 2.3 KB
- references/range.md 7.9 KB
- references/screenshot.md 5.1 KB
- references/slicer.md 3.4 KB
- references/table.md 4.8 KB
- references/window.md 5.2 KB
- references/workbook.md 1.9 KB
- references/workflows.md 2.2 KB
- references/worksheet.md 3.6 KB
- references/xmlmap.md 1.7 KB
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago Changed 08d5bdf17013
- 8d ago First seen · 202 lines · 106 tokens per session scan A 67acc774c330
excel-mcp is a skill published in the GitHub repository sbroenne/mcp-server-excel (669 stars, last pushed today), licensed MIT. It adds 106 tokens to every session and 2,065 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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