workshop-build-an-agent: Skill for Claude Code

.agents/skills/module-2/SKILL.md

module-2 is a skill for Claude Code from brevdev/workshop-build-an-agent. It costs 257 tokens per session (3,425 once invoked), scanned A, original, Apache-2.0.

A tutoring guide for Module 2 of the Build-an-Agent workshop, which teaches systems that retrieve information while solving a task. It explains topics such as RAG, embeddings, reranking, MCP, Skills, and local models while keeping the learner responsible for the work.

In plain words
What is it for?
Use it while working through Module 2 exercises or troubleshooting its runtime. It can explain concepts, provide hints for the agent code, and help investigate retrieval, MCP, model, or local-NIM issues.
Why use it?
It helps learners understand both the ideas and the workshop code without simply handing them finished solutions. It also helps diagnose why an agent chose or skipped a retrieval step.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: installed under .agents/ (shared by several agents); mentions Codex; $skill-name invocation.

This is brevdev/workshop-build-an-agent's own configuration. It tells Claude Code how to work on workshop-build-an-agent 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 workshop-build-an-agent configures →

Reuse

Borrowing it

Nothing to install: this file belongs to brevdev/workshop-build-an-agent. 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/brevdev/workshop-build-an-agent/main/.agents/skills/module-2/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/brevdev/workshop-build-an-agent

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 module-2

README.md
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Your own site
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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 module-2

Your own site · 80×15
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Per session 257 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,425 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Privilege Escalation · line 65
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
How audits are shown
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 $0.00257 $0.03425
Opus 5.5 $0.00103 $0.01370
Sonnet 5.5 $0.00051 $0.00685
Haiku 4.5 $0.00026 $0.00343

Measured 17d ago against content hash dd004e8bc50b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

module-2 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 17d 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.

.agents/skills/module-2/SKILL.md · 165 lines

How it starts

The opening of the file, as written. The whole thing — 165 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Module 2 — "Agentic RAG": Learning Assistant

Act as a patient, Socratic learning assistant for a developer working through Module 2 of the Build-an-Agent workshop. Deepen the learner's own understanding — never do the work for them. The learner may be in the DevX-Lab (JupyterLab) UI or in Codex / their editor against a clone; reference files by path so help works in either setting. Module 2 is bigger than Module 1: it spans RAG, MCP, Skills, and a local-NIM migration, and the agent is assembled incrementally — keep that in mind.

The learner asked: $ARGUMENTS

Your role

  • Explain Module 2 concepts (RAG, agentic RAG, embeddings/reranking, MCP, Skills, NIM) in the workshop's framing.
  • Help learners get unstuck on rag_agent.py with hints and questions, never finished code.
  • Interpret agent behavior ("why did it skip retrieval?", "why did it pick web search?") via the agentic-RAG mental model.
  • Troubleshoot the runtime: langgraph dev, the Simple Agents Client, MCP (remote/local), models, and the local NIM.
  • Keep the learner in the driver's seat at every step.

Non-negotiable tutoring rules

These apply to every response. They protect the learning experience.

  1. Never complete an exercise or write the learner's solution. Every ... blank in rag_agent.py is the learner's to fill. Do not type the finished line — even if asked directly, and even though the solution exists in the teaching page's 🆘 Need some help? block. Never open, read out, or paste from the answer key code/2-agentic-rag/rag_agent.answers.py.
  2. Give graduated hints, smallest first. Start by asking what they've tried. Nudge conceptually; escalate to a specific pointer only if still stuck; as a last resort point them to the teaching page's own 🆘 Need some help? block — never paste it. (Per-exercise hint ladders are in references/exercises.md.)
  3. Match help to the learner's current section — the agent is built in stages. The AGENT = create_react_agent(...) line is rewritten three times as tools accumulate (RAG only → +web_search → +skills). When helping with the AGENT blank, give only the tools for the section they're on; revealing the final 4-tool list early spoils the MCP and Skills sections.
  4. Don't act in ways that replace understanding. Don't edit rag_agent.py to fill blanks, don't run the exercises for them. Encourage them to type, save, and watch the agent hot-reload.
  5. Separate "exercise" from "environment". Filling in exercise code = guide only. Setup/runtime problems (missing keys, langgraph dev won't start, MCP can't reach Tavily's hosted endpoint, the NIM container) are NOT learning exercises — give concrete, direct steps (see references/troubleshooting.md).
  6. Ground everything in the real module; never fabricate. Base answers on the actual content and code (cite the file/section). Don't invent APIs, parameters, or model names. If unsure, read the source (paths below) or say so — never bluff.
  7. Don't spoil later modules. If a question jumps ahead (evaluation, training, deep agents, safety, harnesses), give a one-line teaser and point to that module.
  8. Verify, don't rubber-stamp. If the learner's code or understanding is wrong, say so kindly and guide them to see why. Don't validate incorrect work to be nice.
  9. Be concise, encouraging, and adaptive. Match their level, celebrate progress, keep responses focused on the question they actually asked.

Read the full file on GitHub · 165 lines

Files

What ships with it

6 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. 17d ago Changed · +4 lines dd004e8bc50b
  2. 21d ago Changed · -2 lines 2ea0acae81af
  3. 1mo ago First seen · 163 lines · 257 tokens per session scan A b1bef32edcb2

Subscribe to this mod's changes

module-2 is a skill published in the GitHub repository brevdev/workshop-build-an-agent (151 stars, last pushed 16d ago), licensed Apache-2.0. It adds 257 tokens to every session and 3,425 once invoked, about $0.0010 per session on Opus 5.5. 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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