tlx: Instructions file for Claude Code

CLAUDE.md

tlx CLAUDE.md is an instructions file for Claude Code from jrjsmrtn/tlx. It costs 2,140 tokens per session, scanned A, original, MIT.

Project instructions for TLX, an Elixir library that turns formal specifications into formats such as TLA+, diagrams, and simulations. TLA+ is a language for describing and checking how systems behave over time.

In plain words
What is it for?
Use them when working on TLX’s specification tools, importers, simulators, extractors, visualizations, or checks for outdated specifications.
Why use it?
They give coding agents the project’s architecture, current status, deliverables, and available agent skills so changes match the library’s intended design.

Instructions file for Claude Code

Written for Claude Code: the file is CLAUDE.md. Also seen: reads .claude/ paths; mentions CLAUDE.md; mentions AGENTS.md.

This is jrjsmrtn/tlx's own configuration. It tells Claude Code how to work on tlx itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything tlx configures →

View source ↗ jrjsmrtn/tlx
Reuse

Borrowing it

Nothing to install: this file belongs to jrjsmrtn/tlx. 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/jrjsmrtn/tlx/main/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/jrjsmrtn/tlx

Made for: Claude Code.

Wrote this? Show the measurements

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README.md
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Per session 2,140 This file is loaded in full into every session.
When invoked 2,140 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 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 $0.02140 $0.02140
Opus 5 $0.01070 $0.01070
Sonnet 5 $0.00428 $0.00428
Haiku 4.5 $0.00214 $0.00214

Measured 6d ago against content hash a16e2cd58e15, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

tlx CLAUDE.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 6d 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.md · 144 lines

How it starts

The opening of the file, as written. The whole thing — 144 lines — stays where its author put it; the contents beside it link to each section on GitHub.

TLX

A Spark DSL for writing TLA+/PlusCal specifications, with TLA+ emission for TLC model checking and an optional Elixir simulation mode.

Deliverables

TLX library — Elixir DSL for formal specifications. Emits TLA+, PlusCal (C/P syntax), Elixir (round-trip), DOT, Mermaid, PlantUML, D2. Includes NimbleParsec importers, Elixir simulator, TLC integration, refinement checking, 7 extractors (gen_statem, GenServer, LiveView, Erlang, Ash.StateMachine, Reactor, Broadway), 3 OTP patterns (StateMachine, GenServer, Supervisor).

Agent skills — 4 skills shipped via usage-rules/skills/ per agentskills.io spec, distributed to consumers via usage_rules package_skills: [:tlx]: formal-spec (ADR → abstract spec → extract → enrich → refinement), spec-audit (scan project for extractable modules), visualize (multi-format diagrams), spec-drift (detect stale specs).

Project Context

  • Category: Development
  • Type: Library + Agent Skill
  • Stack: Elixir/Spark
  • License: MIT

Current Development Status

  • Latest Release: v0.5.3
  • Status: Active — 5 examples, 609 unit + 91 integration tests, Diátaxis docs complete
  • Completed sprints: 1-70 + refinement (ADR-0013 round-trip track shipped)
  • Proposed sprints: 44 (state/transition coverage tooling)

Foundational ADRs

Read these at the start of each AI session for complete context:

ADR Purpose Summary
ADR-0001 HOW TO DECIDE Decision methodology
ADR-0002 HOW TO DEVELOP Development practices
ADR-0003 WHAT TECH Technology stack

Read the full file on GitHub · 144 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. 6d ago First seen · 144 lines · 2,140 tokens per session scan A a16e2cd58e15

Subscribe to this mod's changes

tlx CLAUDE.md is an instructions file published in the GitHub repository jrjsmrtn/tlx (10 stars, last pushed 1mo ago), licensed MIT. It adds 2,140 tokens to every session, about $0.0107 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.

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