What is sailfin runtime.instructions.md?

Project instructions for Sailfin, a self-hosted systems programming language with effect handling and compile-time checks on which operations code may perform.

Use them when asking an agent to work on the Sailfin codebase or understand its language and capability system.

They give a coding agent the project’s rules and technical context so its changes fit the repository.

How SailfinIO/sailfin configures GitHub Copilot

Reuse

Borrowing it

Nothing to install: this file belongs to SailfinIO/sailfin. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/SailfinIO/sailfin/main/.github/instructions/runtime.instructions.md

Clone the repo

git clone --depth 1 https://github.com/SailfinIO/sailfin

Made for: GitHub Copilot.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/sailfinio/sailfin/runtime/github.svg)](https://agentmods.dev/instructions/sailfinio/sailfin/runtime)

Your own site

<a href="https://agentmods.dev/instructions/sailfinio/sailfin/runtime"><img src="https://agentmods.dev/badge/instructions/sailfinio/sailfin/runtime/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/sailfinio/sailfin/runtime"><img src="https://agentmods.dev/badge/instructions/sailfinio/sailfin/runtime.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 205 This file is loaded in full into every session.

When invoked 205 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin unknown No closer match found in the catalogue.

Token cost

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	$0.00205	$0.00205
Opus 5.5	$0.00082	$0.00082
Sonnet 5.5	$0.00041	$0.00041
Haiku 4.5	$0.00020	$0.00020

Measured 1mo ago against content hash 98befe4cef79, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

sailfin runtime.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 1mo 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.

.github/instructions/runtime.instructions.md · 14 lines

The source is not reproduced here

Licensed GPL-2.0

The repository is licensed GPL-2.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

Changes

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.

1mo ago First seen · 14 lines · 205 tokens per session scan A 98befe4cef79

Subscribe to this mod's changes

sailfin runtime.instructions.md is an instructions file published in the GitHub repository SailfinIO/sailfin (8 stars, last pushed 2d ago), licensed GPL-2.0. It adds 205 tokens to every session, about $0.0008 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 2026-10-02.

Languages capability-based-security compile-time-safety compiler concurrency programming-language runtime

sailfin runtime.instructions.md next to 6 instructions from other repositories
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sailfin: Instructions file for GitHub Copilot