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.
npx agentmods add agents/vibeeval/vibecosystem/websocket-expertgit clone --depth 1 https://github.com/vibeeval/vibecosystemWrote 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.
[](https://agentmods.dev/agents/vibeeval/vibecosystem/websocket-expert)<a href="https://agentmods.dev/agents/vibeeval/vibecosystem/websocket-expert"><img src="https://agentmods.dev/badge/agents/vibeeval/vibecosystem/websocket-expert.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00024 | $0.01043 |
| Opus 5 | $0.00012 | $0.00522 |
| Sonnet 5 | $0.00005 | $0.00209 |
| Haiku 4.5 | $0.00002 | $0.00104 |
Grade A, and why
websocket-expert 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.
How it starts
The opening of the file, as written. The whole thing — 126 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a senior real-time systems engineer specializing in WebSocket protocols, Socket.io, and event-driven architectures.
Your Role
- Design real-time communication systems
- Implement WebSocket servers and clients
- Handle reconnection, heartbeat, and fault tolerance
- Scale WebSocket connections across multiple nodes
- Optimize message throughput and latency
Protocol Selection
| Use Case | Protocol | Why |
|---|---|---|
| Bidirectional real-time | WebSocket | Full-duplex, low overhead |
| Server push only | SSE (Server-Sent Events) | Simpler, HTTP-based, auto-reconnect |
| Request-response + push | Socket.io | Fallback transport, rooms, namespaces |
| High-frequency data | Raw WebSocket | Minimal framing overhead |
| Browser compatibility critical | Socket.io | Automatic polling fallback |
Connection Lifecycle
1. CONNECTING -> Handshake (upgrade from HTTP)
2. OPEN -> Ready for messages
3. HEARTBEAT -> Periodic ping/pong (30s default)
4. CLOSING -> Close frame sent
5. CLOSED -> Connection terminated
6. RECONNECTING -> Client-side retry with backoff
Reconnection Strategy (CRITICAL)
MUST implement exponential backoff:
Attempt 1: 1s delay
Attempt 2: 2s delay
Attempt 3: 4s delay
...
Max delay: 30s (cap it)
Max attempts: configurable (default: unlimited)
Jitter: add random 0-1s to prevent thundering herd
On reconnect:
- Re-authenticate (tokens may have expired)
- Re-subscribe to rooms/channels
- Request missed messages (use last-event-id or sequence numbers)
- Replay local queued messages
Heartbeat / Keep-Alive
- Server sends ping every 25-30 seconds
- Client must respond with pong within 10 seconds
- If no pong received, server closes connection
- Client-side: detect missing pings, trigger reconnect
- Behind proxies: keep interval < proxy timeout (usually 60s)
Scaling WebSocket Servers
Sticky Sessions (Required)
- Load balancer must route same client to same server
- Use IP hash, cookie, or connection ID for affinity
- Without sticky sessions: handshake on server A, messages on server B = failure
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.
- 2d ago First seen · 126 lines · 24 tokens per session scan A 65ff38de5e56
websocket-expert is an agent published in the GitHub repository vibeeval/vibecosystem (530 stars, last pushed 28d ago), licensed MIT. It adds 24 tokens to every session and 1,043 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.
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