runtime-remsh

A guide for connecting to a running Lemon or lemon-gateway BEAM node, an Elixir runtime process, and executing code inside it.

In plain words
What is it for?
Use it to attach with IEx or remote procedure calls, run recompile(), and execute Elixir code in the running node.
Why use it?
It lets developers reload changed Elixir code or inspect and operate the live runtime without restarting the service.

Skill for Claude CodeCodex

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 skills/z80dev/lemon/runtime-remsh
Any agent
npx skills add z80dev/lemon --skill runtime-remsh
Clone the repo
git clone --depth 1 https://github.com/z80dev/lemon

Made for: Claude Code, Codex.

Per session 45 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 821 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 $0.00045 $0.00821
Opus 5 $0.00023 $0.00411
Sonnet 5 $0.00009 $0.00164
Haiku 4.5 $0.00005 $0.00082

Measured 2d ago against content hash f26d41f6f4f8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

runtime-remsh 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.

apps/lemon_skills/priv/builtin_skills/runtime-remsh/SKILL.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

runtime-remsh

Use this skill when the user asks to connect to a running Lemon instance, recompile changed Elixir code without restarting, or run Elixir inside the live runtime.

Trigger

Use this skill for requests like:

  • "connect to the running gateway"
  • "attach to lemon and run recompile()"
  • "execute this Elixir in the live runtime"
  • "run rpc-eval against the node"

Preconditions

  • The target process must be started as a distributed node (--sname or --name) with a cookie.
  • The attaching shell must use the same naming mode and same cookie.
  • For ./bin/lemon-gateway, do not use --no-distribution.

Quickstart (local gateway)

Start gateway (terminal 1):

./bin/lemon-gateway

Attach from another terminal (short-name default):

iex --sname lemon_attach --cookie lemon_gateway_dev_cookie --remsh "lemon_gateway@$(hostname -s)"

If gateway was started with explicit settings, use those exact values:

./bin/lemon-gateway --sname lemon_gateway --cookie "change-me"
iex --sname lemon_attach --cookie "change-me" --remsh "lemon_gateway@$(hostname -s)"

For long-name mode:

./bin/lemon-gateway --name [email protected] --cookie "change-me"
iex --name [email protected] --cookie "change-me" --remsh [email protected]

Tip: ./bin/lemon-gateway prints the exact Remote shell target to use.

Recompile changed code in the live runtime

Inside attached IEx:

recompile()

Useful follow-up checks:

node()
Application.started_applications() |> Enum.map(&elem(&1, 0))

If needed, force reload a module:

r(LemonGateway.Run)

Execute arbitrary Elixir code in the live runtime

Interactive (--remsh) examples:

LemonGateway.Config.get()
LemonGateway.Config.get(:default_engine)

Non-interactive one-off (--rpc-eval) example:

elixir --sname lemon_probe --cookie lemon_gateway_dev_cookie --rpc-eval "lemon_gateway@$(hostname -s)" "IO.inspect(LemonGateway.Config.get(:default_engine))"

Read the full file on GitHub · 118 lines

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 · 118 lines · 45 tokens per session scan A f26d41f6f4f8

Subscribe to this mod's changes

runtime-remsh is a skill published in the GitHub repository z80dev/lemon (129 stars, last pushed 2d ago), licensed MIT. It adds 45 tokens to every session and 821 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 2026-08-30.

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