agentsh AGENTS.md

Repository instructions for Agentsh, a Go project that builds for Linux, macOS, and Windows. They explain cross-platform paths, operating-system-specific code, and tests.

In plain words
What is it for?
Use them when adding platform-specific code, handling paths or temporary files, writing tests, or checking Windows builds.
Why use it?
They prevent code from working on one operating system while failing to build or behave correctly on another.

Instructions file for CodexOpenCode

Install

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.

agentmods
npx agentmods add instructions/canyonroad/agentsh/agents-md
Clone the repo
git clone --depth 1 https://github.com/canyonroad/agentsh

Made for: Codex, OpenCode.

Per session 433 This file is loaded in full into every session.
When invoked 433 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original 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.

ModelPer sessionOnce invoked
Fable 5 $0.00433 $0.00433
Opus 5 $0.00217 $0.00217
Sonnet 5 $0.00087 $0.00087
Haiku 4.5 $0.00043 $0.00043

Measured 3d ago against content hash a8c26e2efe37, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

agentsh 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 3d 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.

AGENTS.md · 52 lines

What it actually says

Agent Guidelines

This project cross-compiles to Linux, macOS, and Windows. Follow these rules.

Paths

  • Use filepath.Join() for all path construction
  • Use os.TempDir() instead of hardcoded /tmp
  • Use filepath.Separator if you need the separator character
  • Never hardcode / or \ as path separators

OS-Specific Code

  • Use build tags for platform-specific files: //go:build linux, //go:build darwin, //go:build windows
  • Check runtime.GOOS for runtime platform detection
  • Skip platform-specific tests with t.Skip() when features aren't available

Common Platform Differences

Feature Linux macOS Windows
Unix sockets Yes Yes No
PTY /dev/ptmx /dev/ptmx ConPTY
Resource limits cgroups RLIMIT_* Job Objects
Signals Full POSIX Full POSIX Limited
$0 / argv[0] Works Works Different

Testing

  • Run GOOS=windows go build ./... to verify Windows compilation
  • Tests using Unix sockets, POSIX signals, or shell features should skip on Windows
  • Use t.TempDir() for test directories (auto-cleaned)

CI-Specific Issues

ConPTY tests hang in CI: Windows ConPTY doesn't properly signal EOF in non-interactive environments. Tests using ConPTY should skip in CI:

func skipInCI(t *testing.T) {
    t.Helper()
    if os.Getenv("CI") != "" || os.Getenv("GITHUB_ACTIONS") != "" {
        t.Skip("skipping ConPTY test in CI")
    }
}

Environment Variables

  • Use os.Getenv() / os.Setenv()
  • On Windows, env vars are case-insensitive but Go preserves case
  • Use os.Environ() to get the full environment as KEY=value slice
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.

  1. 3d ago First seen · 52 lines · 433 tokens per session scan A a8c26e2efe37

Subscribe to this mod's changes

agentsh AGENTS.md is an instructions file published in the GitHub repository canyonroad/agentsh (380 stars, last pushed 27d ago), licensed Apache-2.0. It adds 433 tokens to every session, about $0.0022 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.