What is lane-layout-debugger?

A debugging workflow for SnowGram diagrams that arrange nodes into lanes and sections. It focuses on the code that converts Mermaid diagrams into React Flow layouts.

Use it when lane or section badges are missing, nodes are scattered, or a diagram does not match its reference PDF. It points developers to the relevant layout code and tests.

It helps distinguish actual layout bugs from layouts that are working as designed. It also provides checks for missing badges, scattered nodes, and incorrect streaming diagrams.

lane-layout-debugger — Skill for Claude Code and Codex by sfc-gh-abann

Install

Getting it into your agent

There is no command for this one: it runs only inside a plugin, and the catalogue could not identify which plugin ships it. The source is linked below.

Made for: Claude Code, Codex.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/sfc-gh-abannerjee/snowgram/lane-layout-debugger/github.svg)](https://agentmods.dev/skills/sfc-gh-abannerjee/snowgram/lane-layout-debugger)

Your own site

<a href="https://agentmods.dev/skills/sfc-gh-abannerjee/snowgram/lane-layout-debugger"><img src="https://agentmods.dev/badge/skills/sfc-gh-abannerjee/snowgram/lane-layout-debugger/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/sfc-gh-abannerjee/snowgram/lane-layout-debugger"><img src="https://agentmods.dev/badge/skills/sfc-gh-abannerjee/snowgram/lane-layout-debugger.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 64 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 2,036 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.

Model	Per session	Once invoked
Fable 5.1	$0.00064	$0.02036
Opus 5	$0.00032	$0.01018
Sonnet 5	$0.00013	$0.00407
Haiku 4.5	$0.00006	$0.00204

Measured 8d ago against content hash c1beba22adf1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

lane-layout-debugger 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 8d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (run_debug_loop.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.cortex/skills/lane-layout-debugger/SKILL.md · 233 lines

How it starts

The opening of the file, as written. The whole thing — 233 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Lane Layout Debugger

Inherits: $snowgram-debugger (generalized debug loop) Specialization: Lane-based layout system in mermaidToReactFlow.ts and elkLayout.ts

⚡ Quick Start (Skip if already ran tests)

Most lane layout "bugs" are actually working correctly. Before debugging, run:

cd /Users/abannerjee/Documents/SnowGram/frontend && npm test -- --grep "lane"

If tests pass → The code is correct. Check browser console for usedLaneLayout: true.

When to Use This Skill

Use $lane-layout-debugger instead of $snowgram-debugger when the bug involves:

Lane badges (1A, 1B, 1C, 1D) not appearing
Section badges (2, 3, 4, 5) not appearing
Nodes scattered instead of organized in lanes
usedLaneLayout: false in console
Streaming template not matching reference PDF

Domain-Specific Context

Code Path

User clicks template → App.tsx → parseMermaidToReactFlow()
                                        ↓
                          mermaidToReactFlow.ts (lines 389-577)
                          - Parse subgraph lines
                          - Call buildSubgraphLayoutInfo()
                          - Apply metadata to nodes (lines 540-559)
                                        ↓
                          Returns { nodes, edges, subgraphs, layoutInfo }
                                        ↓
                          App.tsx (lines 3038-3050)
                          - Check if layoutInfo.size > 0
                          - Call layoutWithLanes()
                                        ↓
                          elkLayout.ts (lines 458-466)
                          - Check hasLayoutMetadata
                          - If true: Apply lane layout with badges
                          - If false: Standard layout (no badges)

Key Files

File	Lines	Purpose
`frontend/src/lib/mermaidToReactFlow.ts`	389	`subgraphStartRegex` - parses subgraph lines
`frontend/src/lib/mermaidToReactFlow.ts`	228-301	`detectSubgraphLayoutType()` - classifies subgraphs
`frontend/src/lib/mermaidToReactFlow.ts`	540-559	Metadata application loop
`frontend/src/lib/elkLayout.ts`	458-466	`hasLayoutMetadata` check
`frontend/src/App.tsx`	3038-3050	Pipeline orchestration

Read the full file on GitHub · 233 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

run_debug_loop.sh 2.6 KB runs code

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.

8d ago First seen · 233 lines · 64 tokens per session scan A c1beba22adf1

Subscribe to this mod's changes

lane-layout-debugger is a skill published in the GitHub repository sfc-gh-abannerjee/SnowGram (2 stars, last pushed 3mo ago), licensed MIT. It adds 64 tokens to every session and 2,036 once invoked, about $0.0003 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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