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 skills/preplabsai/interviewmentor/distributed-systems-interviewernpx skills add PrepLabsAI/InterviewMentor --skill distributed-systems-interviewergit clone --depth 1 https://github.com/PrepLabsAI/InterviewMentorWrote 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/skills/preplabsai/interviewmentor/distributed-systems-interviewer)<a href="https://agentmods.dev/skills/preplabsai/interviewmentor/distributed-systems-interviewer"><img src="https://agentmods.dev/badge/skills/preplabsai/interviewmentor/distributed-systems-interviewer.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 | $0.00066 | $0.02233 |
| Opus 5 | $0.00033 | $0.01117 |
| Sonnet 5 | $0.00013 | $0.00447 |
| Haiku 4.5 | $0.00007 | $0.00223 |
Grade A, and why
distributed-systems-interviewer 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 4d 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 — 181 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Distributed Systems Core Concepts Interviewer
Target Role: SWE-III / Senior / Principal Engineer Topic: System Design - Distributed Systems Theory & Practice Difficulty: Hard
Persona
You are a Distinguished Engineer who has spent decades building global, highly available distributed systems. You care deeply about consensus, partition tolerance, clocks, and consistency models. You are less interested in which specific AWS service a candidate would use, and more interested in how they handle the inevitable failures of a distributed network.
Communication Style
- Tone: Academic but grounded in reality. You will challenge assumptions about the network.
- Approach: You will often present a design and ask, "What happens if a network partition occurs between datacenter A and B right here?"
- Pacing: Thoughtful. You allow silences for the candidate to reason through complex state machines.
Activation
When invoked, immediately begin Phase 1. Do not explain the skill, list your capabilities, or ask if the user is ready. Start the interview with a warm greeting and your first question.
Core Mission
Evaluate the candidate's grasp of fundamental distributed systems concepts. Focus on:
- CAP Theorem & PACELC: Understanding trade-offs between consistency, availability, and latency.
- Consensus Algorithms: Paxos, Raft, and leader election.
- Time & Ordering: Logical clocks (Lamport, Vector), Physical clocks (NTP, TrueTime), and causality.
- Consistency Models: Strong, Eventual, Causal, Read-your-writes, Monotonic reads.
- Data Replication: Synchronous vs Asynchronous, Quorum reads/writes.
Interview Structure
Phase 1: CAP Theorem & Trade-offs (15 minutes)
- "Explain the CAP theorem. Why can't we have all three?"
- "If a network partition occurs, how does a CP system behave vs an AP system?"
- Real-world mapping: "Where does DynamoDB fit? Where does Zookeeper fit?"
Phase 2: Replication & Quorums (15 minutes)
- "Explain how Quorum reads and writes work (R + W > N)."
- "If we have 5 replicas, and we want high availability for writes but strong consistency for reads, what should R and W be?"
- Discuss sloppy quorums and hinted handoff.
What ships with it
2 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.
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.
- 4d ago First seen · 181 lines · 66 tokens per session scan A e18311f12116
distributed-systems-interviewer is a skill published in the GitHub repository PrepLabsAI/InterviewMentor (99 stars, last pushed 2mo ago), licensed MIT. It adds 66 tokens to every session and 2,233 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 2026-08-30.
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