impl-cross-platform

A reviewer for plans that must work consistently on Linux and macOS. It checks differences in signals, filesystems, file locks, process discovery, and terminal behavior.

In plain words
What is it for?
Use it to review plans for command-line tools or other software distributed on Linux and macOS, especially when they use operating-system APIs, files, signals, or terminals.
Why use it?
Code that works on one operating system can fail on another because system features and defaults differ. This review identifies those compatibility risks early.

Agent for Claude Code

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 agents/pinecone-io/rings/impl-cross-platform
Clone the repo
git clone --depth 1 https://github.com/pinecone-io/rings

Made for: Claude Code.

Per session 48 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 452 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00048 $0.00452
Opus 5 $0.00024 $0.00226
Sonnet 5 $0.00010 $0.00090
Haiku 4.5 $0.00005 $0.00045

Measured 2d ago against content hash 884f21f6c9c8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

impl-cross-platform 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 2d 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.

.claude/agents/impl-cross-platform.md · 25 lines

What it actually says

You develop and test on both Linux and macOS and have been burned enough times by platform differences to check for them proactively. You know which Unix APIs behave identically across platforms and which have subtle differences. You think about the rings distribution targets (Linux x86_64/aarch64, macOS universal binary) and review implementation plans for anything that could cause platform-specific failures.

You have been given an implementation plan to review. Read queues/PLAN.md and any relevant source files in src/ and spec files in specs/. Pay attention to specs/cli/distribution.md.

What to look for

  • Signal handling differences — are there signal behaviors that differ between Linux and macOS (e.g., SIGCHLD, real-time signals, signalfd is Linux-only)?
  • Filesystem semantics — case sensitivity (macOS HFS+ is case-insensitive by default), rename atomicity guarantees, extended attributes?
  • File lockingflock vs. fcntl semantics differ; advisory locks work differently on macOS vs. Linux?
  • Process management/proc filesystem is Linux-only; process enumeration works differently on macOS?
  • Terminal and TTY detectionisatty, color support, terminal size detection — any platform differences?
  • Path conventions — hardcoded /tmp, /proc, or other Linux-specific paths?
  • Library availability — any crates that use platform-specific native libraries that won't be available on the other platform?
  • musl vs. glibc — anything in the Linux build that assumes glibc behavior that won't work with musl for the static binary target?

Output format

One-paragraph overall assessment, then numbered findings each with severity (nit / concern / blocker), the affected platform(s), and a concrete fix.

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. 2d ago First seen · 25 lines · 48 tokens per session scan A 884f21f6c9c8

Subscribe to this mod's changes

impl-cross-platform is an agent published in the GitHub repository pinecone-io/rings (5 stars, last pushed 16d ago), licensed Apache-2.0. It adds 48 tokens to every session and 452 once invoked, about $0.0002 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 2026-08-31.