oppertunity-party: Skill for Claude Code

.agents/skills/mermaid-diagrams/SKILL.md

mermaid-diagrams is a skill for Claude Code, Codex from mcwalrus/oppertunity-party. It costs 160 tokens per session (2,613 once invoked), scanned A, original, MIT.

A guide for creating Mermaid diagrams, which are text-based diagrams that can render in tools such as GitHub, GitLab, or Notion. It focuses on software, infrastructure, workflows, data, and platform systems.

In plain words
What is it for?
Use it for architecture diagrams, pull requests, ADRs, RFCs, runbooks, incident reviews, roadmaps, deployment pipelines, data models, and service layouts.
Why use it?
It helps you choose a diagram that answers one clear question and produce Mermaid code that renders correctly.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is mcwalrus/oppertunity-party's own configuration. It tells Claude Code and Codex how to work on oppertunity-party 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 oppertunity-party configures →

Reuse

Borrowing it

Nothing to install: this file belongs to mcwalrus/oppertunity-party. 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/mcwalrus/oppertunity-party/main/.agents/skills/mermaid-diagrams/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/mcwalrus/oppertunity-party

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.

agentmods badge for mermaid-diagrams

README.md
[![agentmods](https://agentmods.dev/badge/skills/mcwalrus/oppertunity-party/mermaid-diagrams/github.svg)](https://agentmods.dev/skills/mcwalrus/oppertunity-party/mermaid-diagrams)
Your own site
<a href="https://agentmods.dev/skills/mcwalrus/oppertunity-party/mermaid-diagrams"><img src="https://agentmods.dev/badge/skills/mcwalrus/oppertunity-party/mermaid-diagrams/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 mermaid-diagrams

Your own site · 80×15
<a href="https://agentmods.dev/skills/mcwalrus/oppertunity-party/mermaid-diagrams"><img src="https://agentmods.dev/badge/skills/mcwalrus/oppertunity-party/mermaid-diagrams.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 160 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,613 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 $0.00160 $0.02613
Opus 5 $0.00080 $0.01307
Sonnet 5 $0.00032 $0.00523
Haiku 4.5 $0.00016 $0.00261

Measured 11d ago against content hash 5bd306cc070b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

mermaid-diagrams 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 11d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/validate-diagrams.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.

.agents/skills/mermaid-diagrams/SKILL.md · 231 lines

How it starts

The opening of the file, as written. The whole thing — 231 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Mermaid Diagrams for SWE / DevOps / Platform Engineering

You are helping an engineer produce Mermaid diagrams that communicate technical initiatives clearly — changes across codebases, infrastructure, pipelines, data models, and platforms. Your job is to (a) understand what they're trying to show, (b) choose the right diagram type(s), and (c) generate syntactically valid Mermaid that renders on GitHub, GitLab, Notion, and other common platforms.


Workflow

1. Understand the initiative

Before generating anything, get clear on what the user is trying to communicate. Ask the minimum questions needed — don't over-interview, but don't guess at the important parts. Key things to understand:

  • What changed / is changing? (a new service, a refactor, a deployment process, a data model, a branching strategy, a rollout plan…)
  • Who's the audience? (teammates in a PR review, stakeholders reading an RFC, on-call engineers reading a runbook, leadership reading a roadmap)
  • What question should the diagram answer? This is the most important one. A good diagram answers one question clearly. If the user has multiple questions, plan multiple diagrams.

Common questions → diagram types:

Question the diagram should answer Diagram type
Who owns what code / which layer does what? flowchart with subgraphs
What does the data look like at each step? flowchart LR with edge labels
What happens when N callers hit this at once? sequenceDiagram with par/and
What changed (before vs after)? Paired flowchart subgraphs
How do we roll this out / migrate? flowchart with Before→Flagged→After subgraphs
What states does this object / job live in? stateDiagram-v2
How do requests flow through the system? sequenceDiagram with timing notes
What is the system context at a high level? C4Context or C4Container
What does the cloud topology look like? architecture-beta
What's the project / initiative schedule? gantt
What's the branching / release strategy? gitGraph
How do metrics / costs distribute? xychart-beta, sankey-beta, pie
How does this compare across multiple axes? radar-beta
How are requirements / SLAs linked? requirementDiagram
What work is in flight (sprint, incidents)? kanban
How do ideas / capabilities decompose? mindmap
What are the priorities (effort vs impact)? quadrantChart
What does the DB schema look like? erDiagram
What are the domain classes? classDiagram
What's the git branching model? gitGraph

Read the full file on GitHub · 231 lines

Files

What ships with it

5 files 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.

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. 11d ago First seen · 231 lines · 160 tokens per session scan A 5bd306cc070b

Subscribe to this mod's changes

mermaid-diagrams is a skill published in the GitHub repository mcwalrus/oppertunity-party (0 stars, last pushed 19d ago), licensed MIT. It adds 160 tokens to every session and 2,613 once invoked, about $0.0008 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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