Borrowing it
Nothing to install: this file belongs to WillEhrendreich/SageFs. 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/WillEhrendreich/SageFs/master/AGENTS.mdgit clone --depth 1 https://github.com/WillEhrendreich/SageFsWrote 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/willehrendreich/sagefs/agents-md)<a href="https://agentmods.dev/instructions/willehrendreich/sagefs/agents-md"><img src="https://agentmods.dev/badge/instructions/willehrendreich/sagefs/agents-md/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/willehrendreich/sagefs/agents-md"><img src="https://agentmods.dev/badge/instructions/willehrendreich/sagefs/agents-md.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 | $0.10112 | $0.10112 |
| Opus 5.5 | $0.04045 | $0.04045 |
| Sonnet 5.5 | $0.02022 | $0.02022 |
| Haiku 4.5 | $0.01011 | $0.01011 |
Grade A, and why
SageFs AGENTS.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 7d 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 — 531 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SageFs: Coding Agent Guidelines
STOP: Read This Before Anything Else
The SageFs daemon is a long-running process that never exits on its own. It hosts the FSI session, MCP server, and dashboard on ports 37749/37750. You will be tempted to wait for it. DO NOT.
The cardinal rule, stated three times because it is the only thing you keep getting wrong:
-
NEVER narrate a wait to the user. After starting a daemon, do not write "verifying" or "checking" or "started" and then stop. The next thing you produce must be a tool result: specifically a screenshot, an HTTP probe with a hard timeout, or the next concrete step. A chat message that is not a result or a question is the failure mode.
-
NEVER call a command that blocks on the daemon's lifetime.
Wait-Process,Start-Process -Wait, waiting for a process to exit,taskkill /T /Fon the daemon while also awaiting the result, all of these will hang forever because the daemon is not supposed to exit. -
NEVER treat
Start-Sleepas "wait for the daemon to be ready" without a follow-up tool call in the same turn.Start-Sleep 3followed by a chat message is the same hang, just shorter.Start-Sleep 3followed by a screenshot is fine. The sleep is not the problem. The text after the sleep is the problem. -
NEVER re-derive an MCP connection from scratch. Run
dotnet fsi scripts/reconnect-mcp.fsx. If every MCP tool answers404 Session not found, the connection is LIVE and pointing at a session the daemon no longer has. The session lives in the daemon's MEMORY, and installing a build restarts the daemon on purpose, so the id a client holds dies. A client on Streamable HTTP sendsinitializeonce and never again, so the failure repeats until someone reloads the client by hand.reconnect-mcp.fsxre-initializes and PROVES it (it first requires a never-minted id to be rejected, so a pass cannot mean "the endpoint merely answers"). If it printsOK, you are live; carry on. The durable fix is the stdio bridge,claude mcp add sagefs -- sagefs mcp, which owns the handshake itself, so the client never holds an id at all.scripts/probe-bridge-stdio.fsxdrives that bridge from a script, which is how to dogfood it without a client. Full explanation: "404 Session not found" indocs/mcp-tools.md, and the same diagnosis inskills/sagefs/troubleshooting.md, which also says to check the daemon's version before believing anything else.
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.
- 7d ago Changed · +14 lines · +317 tokens per session 81a5aa5de58e
- 9d ago Changed · +80 lines · +1,345 tokens per session 77d3f15778d8
- 11d ago Changed · +8 lines · +256 tokens per session a4c8e86e70c5
- 25d ago Changed · +95 lines · +2,033 tokens per session c34d2f7155b2
- 27d ago Changed · +37 lines · +1,310 tokens per session 0b1b56afdde6
- 28d ago Changed · +22 lines · +447 tokens per session 37f0f090ab56
- 29d ago Changed · +83 lines · +1,294 tokens per session 3f06847945db
- 1mo ago Changed · +21 lines · +397 tokens per session 10f13919d7c4
- 1mo ago Changed · +20 lines · +311 tokens per session f408ee2abbeb
- 1mo ago First seen · 151 lines · 2,402 tokens per session scan A bc363829b7ee
SageFs AGENTS.md is an instructions file published in the GitHub repository WillEhrendreich/SageFs (84 stars, last pushed 5d ago), licensed MIT. It adds 10,112 tokens to every session, about $0.0404 per session on Opus 5.5. 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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