lambda-lang

lambda-lang is a skill for Claude Code from skillmds/skillmd. It costs 43 tokens per session (1,152 once invoked), scanned A, original, MIT.

A compact language for direct messages between AI agents. It uses short codes for structured coordination such as queries, handoffs, acknowledgements, errors, and session state.

In plain words
What is it for?
Use it in agent-to-agent protocols, task delegation, orchestrators, handoffs, and coordination logs.
Why use it?
It reduces repeated natural-language wording when agents exchange structured messages and token usage matters.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the agents-mcp plugin — 34 skills shipped together

Good fit Use it in agent-to-agent protocols, task delegation, orchestrators, handoffs, and coordination logs.

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Install with agentmods
npx agentmods add skills/skillmds/skillmd/lambda-lang
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.

Any agent
npx skills add skillmds/skillmd --skill lambda-lang
Clone the repo
git clone --depth 1 https://github.com/skillmds/skillmd

Made for: Claude Code.

Or install agents-mcp, the plugin that ships this one along with the rest of its 34 skills.

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.

agentmods badge for lambda-lang

README.md
[![agentmods](https://agentmods.dev/badge/skills/skillmds/skillmd/lambda-lang/github.svg)](https://agentmods.dev/skills/skillmds/skillmd/lambda-lang)
Your own site
<a href="https://agentmods.dev/skills/skillmds/skillmd/lambda-lang"><img src="https://agentmods.dev/badge/skills/skillmds/skillmd/lambda-lang/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.

agentmods 80×15 button for lambda-lang

Your own site · 80×15
<a href="https://agentmods.dev/skills/skillmds/skillmd/lambda-lang"><img src="https://agentmods.dev/badge/skills/skillmds/skillmd/lambda-lang.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,152 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00043 $0.01152
Opus 5.5 $0.00017 $0.00461
Sonnet 5 $0.00009 $0.00230
Haiku 4.5 $0.00004 $0.00115

Measured 4d ago against content hash 5f68b102463b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-23, from the pricing page.

Security

Grade A, and why

lambda-lang 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 4d 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.

plugins/agents-mcp/skills/lambda-lang/SKILL.md · 114 lines

How it starts

The opening of the file, as written. The whole thing — 114 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Λ (Lambda) Language

Lambda is not a translation protocol. It is a native language for agents.

Agents do not need to produce grammatically correct English to coordinate — they need to understand each other. Lambda is the shared vocabulary that makes that possible: compact, unambiguous, machine-native. Compression (3x vs natural language, 4.6x vs JSON on single messages) is a side effect of removing human redundancy, not the goal.

When to Use This Skill

  • Use for agent-to-agent messaging in A2A protocols, orchestrators, task delegation, or handoff pipelines.
  • Use when logging structured coordination signals where every token costs money (heartbeats, acknowledgements, error classes, session state).
  • Use when both sides of a channel speak Λ — do not use against humans or any surface requiring legal/exact natural language.

How It Works

Step 1: Recognize the Syntax

Lambda messages are built from atoms. Every atom is a 2-character code mapped to a concept — not to an English word. The structure is Type → Entity → Verb → Object, with prefixes marking intent:

  • ? — query (e.g. ?Uk/co — query: "does this user have consciousness?")
  • ! — assertion / declaration (e.g. !It>Ie — "self reflects, therefore self exists")
  • # — state / tag
  • > — implication / flow
  • / — binding / scope

Step 2: Pick the Right Domain

Lambda ships 340+ atoms across 7 domains. Pick atoms from the domain that fits your channel:

  • core — universal atoms (always available)
  • code — software engineering, build, test, deploy
  • evo — agent evolution, gene, capsule, mutation, rollback
  • a2a — node, heartbeat, publish, subscribe, route, transport, session, cache, broadcast, discover (39 atoms)
  • emotion — affective state, drive, appraisal
  • social — trust, alignment, reputation, coordination
  • general — everything else

Step 3: Emit and Parse

Both agents need the same atom table loaded. Lossy decoding is fine: if A says !It>Ie and B understands "self reflects, therefore self exists," communication succeeded — the exact English phrasing is irrelevant.

Read the full file on GitHub · 114 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. 4d ago First seen · 114 lines · 43 tokens per session scan A 5f68b102463b

Subscribe to this mod's changes

lambda-lang is a skill published in the GitHub repository skillmds/skillmd (1 stars, last pushed yesterday), licensed MIT. It adds 43 tokens to every session and 1,152 once invoked, about $0.0002 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 2026-09-19.