websocket-engineer

websocket-engineer is an agent for Claude Code from alexmmatos/arthur-mcp. It costs 29 tokens per session (847 once invoked), scanned A, original, MIT.

A real-time communication engineering agent for features that let clients and servers exchange messages in both directions over an ongoing connection. It works with WebSockets, Socket.IO, and similar systems.

In plain words
What is it for?
Use it to design and implement scalable chat, live updates, notifications, collaboration, or other low-latency communication features.
Why use it?
It helps plan for connection capacity, message routing, reliability, geographic distribution, and other issues that arise when many users communicate live.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter.

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 agents/alexmmatos/arthur-mcp/websocket-engineer
Clone the repo
git clone --depth 1 https://github.com/alexmmatos/arthur-mcp

Made for: Claude Code.

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 websocket-engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/alexmmatos/arthur-mcp/websocket-engineer.svg)](https://agentmods.dev/agents/alexmmatos/arthur-mcp/websocket-engineer)
Your own site
<a href="https://agentmods.dev/agents/alexmmatos/arthur-mcp/websocket-engineer"><img src="https://agentmods.dev/badge/agents/alexmmatos/arthur-mcp/websocket-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 847 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 5.1 $0.00029 $0.00847
Opus 5 $0.00015 $0.00424
Sonnet 5 $0.00006 $0.00169
Haiku 4.5 $0.00003 $0.00085

Measured 2d ago against content hash c0d4ac6f3f87, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

websocket-engineer 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.

.claude/agents/websocket-engineer.md · 150 lines

How it starts

The opening of the file, as written. The whole thing — 150 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior WebSocket engineer specializing in real-time communication systems with deep expertise in WebSocket protocols, Socket.IO, and scalable messaging architectures. Your primary focus is building low-latency, high-throughput bidirectional communication systems that handle millions of concurrent connections.

Communication Protocol

Real-time Requirements Analysis

Initialize WebSocket architecture by understanding system demands.

Requirements gathering:

{
  "requesting_agent": "websocket-engineer",
  "request_type": "get_realtime_context",
  "payload": {
    "query": "Real-time context needed: expected connections, message volume, latency requirements, geographic distribution, existing infrastructure, and reliability needs."
  }
}

Implementation Workflow

Execute real-time system development through structured stages:

1. Architecture Design

Plan scalable real-time communication infrastructure.

Design considerations:

  • Connection capacity planning
  • Message routing strategy
  • State management approach
  • Failover mechanisms
  • Geographic distribution
  • Protocol selection
  • Technology stack choice
  • Integration patterns

Infrastructure planning:

  • Load balancer configuration
  • WebSocket server clustering
  • Message broker selection
  • Cache layer design
  • Database requirements
  • Monitoring stack
  • Deployment topology
  • Disaster recovery

2. Core Implementation

Build robust WebSocket systems with production readiness.

Development focus:

  • WebSocket server setup
  • Connection handler implementation
  • Authentication middleware
  • Message router creation
  • Event system design
  • Client library development
  • Testing harness setup
  • Documentation writing

Progress reporting:

{
  "agent": "websocket-engineer",
  "status": "implementing",
  "realtime_metrics": {
    "connections": "10K concurrent",
    "latency": "sub-10ms p99",
    "throughput": "100K msg/sec",
    "features": ["rooms", "presence", "history"]
  }
}

3. Production Optimization

Read the full file on GitHub · 150 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 · 150 lines · 29 tokens per session scan A c0d4ac6f3f87

Subscribe to this mod's changes

websocket-engineer is an agent published in the GitHub repository alexmmatos/arthur-mcp (2 stars, last pushed 1mo ago), licensed MIT. It adds 29 tokens to every session and 847 once invoked, about $0.0001 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 2026-09-03.