Borrowing it
Nothing to install: this file belongs to sbroenne/mcp-server-excel. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/sbroenne/mcp-server-excel/main/.github/instructions/mcp-llm-guidance.instructions.mdgit 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/instructions/sbroenne/mcp-server-excel/mcp-llm-guidance)<a href="https://agentmods.dev/instructions/sbroenne/mcp-server-excel/mcp-llm-guidance"><img src="https://agentmods.dev/badge/instructions/sbroenne/mcp-server-excel/mcp-llm-guidance/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/sbroenne/mcp-server-excel/mcp-llm-guidance"><img src="https://agentmods.dev/badge/instructions/sbroenne/mcp-server-excel/mcp-llm-guidance.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00254 | $0.00254 |
| Opus 5 | $0.00127 | $0.00127 |
| Sonnet 5 | $0.00051 | $0.00051 |
| Haiku 4.5 | $0.00025 | $0.00025 |
Grade A, and why
mcp-server-excel mcp-llm-guidance.instructions.md 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 10d 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.
What it actually says
Shared LLM guidance
skills/shared is the source of truth. Release builds copy it into both agent
skills and generated MCP prompts. Do not hand-edit generated prompt output.
Write for an agent that already understands Excel, JSON, and MCP. Include only repository-specific information:
- Which ExcelMcp tool to choose when nearby tools overlap
- Non-obvious action differences and destructive behavior
- Session, batch, save, and refresh semantics
- Server-specific return shapes or Excel limitations
- Short recovery guidance for predictable errors
- Concrete parameter examples only when schema descriptions are insufficient
Do not duplicate enum catalogs, types, required/optional flags, generic Excel tutorials, protocol syntax, or CLI help. Keep guidance concise and task-oriented. Use plain text markers rather than emojis.
When changing shared guidance:
- Edit the canonical file in
skills/shared. - Build Release to regenerate prompts and skill references.
- Check generated changes for parity, not as an independent source.
- Run the relevant LLM evaluation only when discoverability or workflow choice changed.
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.
- 10d ago First seen · 32 lines · 254 tokens per session scan A 20211568b906
mcp-server-excel mcp-llm-guidance.instructions.md is an instructions file published in the GitHub repository sbroenne/mcp-server-excel (675 stars, last pushed today), licensed MIT. It adds 254 tokens to every session, about $0.0013 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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