How to Build Your First Claude Code Subagent

A meeting agenda tells you what is on the calendar. Good preparation tells you which decisions need your attention, what is missing, and which questions to bring.

In this guide, you will create meeting-prep: a reusable Claude Code assistant that reads the notes you provide and returns a short preparation brief. You describe the job in plain English; Claude creates the configuration file.

This is the AGENT setup guide from video 3, How to Build Your First Claude Code Subagent. It follows the video's three actions: create the agent, customize its instructions, and test it with meeting notes.

What you will build

Your meeting-prep agent will produce five sections:

1. Meeting Objective: what the meeting is intended to achieve.

2. Key Topics: the important points in the supplied material.

3. Decisions Required: choices that still need an answer.

4. Questions to Ask: three to five useful questions.

5. Preparation Checklist: what to review or bring.

The agent's job is preparation. It reads and reports; you review its suggestions and make the decisions.

The earlier daily brief guide covers a scheduled overview of your day. Here, you call a specialist when you have a specific meeting to prepare for.

Before you start

Have Claude Code installed, signed in, and ready to use. Open a session in a folder containing your meeting material. This guide uses Claude Code, rather than a regular Claude chat.

Start with a plain-text or Markdown agenda and notes file. One short file is enough for a first test. Use material you are allowed to share with Claude, and make sure you know which meeting it refers to.

You do not need to write application code. Claude will create a small Markdown file containing settings and instructions.

Step 1: create your personal meeting-prep agent

Paste the complete prompt below into Claude Code. This is the full setup prompt from the video's companion notes.

Create a reusable personal Claude Code subagent named "meeting-prep".

Save it to:
~/.claude/agents/meeting-prep.md

Purpose:
Help me prepare for meetings by reviewing notes, agendas, and relevant project documents that I provide.

Responsibilities:
1. Read the meeting agenda and supporting documents.
2. Identify important topics and decisions.
3. Highlight missing information and unresolved questions.
4. Prepare 3–5 useful questions to ask.
5. Generate a concise meeting preparation checklist.

Configuration:
- Model: sonnet
- Tools: Read, Grep, Glob
- Permissions: Read-only
- Scope: Personal, reusable across projects

Rules:
- Never invent facts or commitments.
- Distinguish confirmed information from recommendations.
- Cite source filenames when possible.
- Never modify, delete, or send anything.
- Ask for missing files if the provided context is insufficient.

Output:
1. Meeting Objective
2. Key Topics
3. Decisions Required
4. Questions to Ask
5. Preparation Checklist

Create the agent configuration file, show me the result, and explain how to invoke it.

Let Claude show you the proposed file. If it asks for permission to create that specific configuration file, review and approve it.

Creating the agent and using it are separate actions. The main Claude Code session writes the configuration once. The saved meeting-prep agent then uses the reading tools specified in that file.

Step 2: check what Claude saved

Ask Claude to show the file at ~/.claude/agents/meeting-prep.md. The ~ means your home folder. This personal location makes the agent available across projects on that machine.

At the top, check for settings like these:

---
name: meeting-prep
description: Prepare for meetings by reviewing supplied agendas, notes, and project documents. Use when asked for meeting preparation, decisions, questions, or a preparation checklist.
tools: Read, Grep, Glob
model: sonnet
---

Below those settings, check that the instructions contain the responsibilities, rules, and five output sections from the setup prompt. The settings above are only the header, not the complete agent file.

“Permissions: Read-only” in the prompt is a request, not a configuration value named read-only. Check the actual tool list: it should contain Read, Grep, Glob, without write, edit, shell, or connected-service tools. Do not add permissionMode: read-only; it is not a supported value.

Read, Grep, and Glob let the agent read files, search their contents, and find filenames. Tool restrictions do not themselves limit reading to a particular meeting folder, so name the intended files when you invoke it.

Claude's subagent documentation explains the personal file location, settings, and tool controls.

Step 3: test it with one meeting

For your first test, give the agent a concrete file, meeting date, and goal.

You can use your own notes, or save this fictional practice example as client-meeting-notes.md in your working folder. The date and details below are illustrative.

Client planning meeting — 18 November 2026, 2:00 PM
Project: an educational video series
Goal: agree on the scope and next review milestone.

Confirmed:
- The client requested three short tutorial videos.
- The outline is ready for review.
- The client needs captions on all three videos.

Open:
- The delivery date has not been agreed.
- The client has not named a final approver.
- The budget is not recorded in these notes.
- We have not confirmed whether translations are required.

Preparation requested:
- Bring the draft outline.
- Bring two possible production schedules.

Use this invocation with the practice file. For a real meeting, replace the filename, date, and objective first.

Use my meeting-prep agent to prepare for the client planning meeting on 18 November 2026 at 2:00 PM.

Read client-meeting-notes.md in the current working folder. Use only that file for this preparation. If you cannot find or read it, ask me for the correct file instead of guessing.

The goal is to agree on the video scope and next review milestone.

Return the agent's five sections: Meeting Objective, Key Topics, Decisions Required, Questions to Ask, and Preparation Checklist.

Cite the source filename for factual claims. Keep confirmed information separate from suggested actions. Do not invent a budget, deadline, approver, or commitment.

Check that Claude delegates to meeting-prep. If it answers directly without using the agent, ask it explicitly to delegate the task to the saved meeting-prep subagent.

What a useful result could look like

Illustrative output, not a recorded Claude run. Wording will vary, but the facts should stay grounded in the file.

Meeting Objective

Agree on the video scope and next review milestone. Source: client-meeting-notes.md.

Key Topics

• Three tutorial videos are requested, with captions.

• The outline is ready for review.

• Translation requirements remain unconfirmed.

Source: client-meeting-notes.md.

Decisions Required

• Agree on a delivery date.

• Name the final approver.

• Confirm the budget.

• Decide whether translations are needed.

These are open items in client-meeting-notes.md, not settled commitments.

Questions to Ask

1. Which delivery date should we plan toward?

2. Who can approve the final outline and videos?

3. What budget should the production options fit?

4. Are translated captions or other languages required?

Preparation Checklist

• Requested: bring the draft outline and two possible schedules.

• Suggested: show how the two schedules differ so the client can choose a review milestone.

The requested items come from client-meeting-notes.md; the comparison is a recommendation.

Step 4: review once, then reuse

Compare the brief with your notes. A useful first run should satisfy these checks:

• It read the intended file and named the source.

• It kept the five requested sections.

• It treated unknown dates, budgets, and approvers as unresolved.

• Its questions address actual gaps.

• Its checklist separates requested preparation from suggestions.

• It did not modify files or send messages.

For the next meeting, invoke meeting-prep again with the new agenda, notes, date, and objective. You do not need to paste the creation prompt each time.

Saved instructions are reusable; old meeting facts are not automatically carried into every new run. Supply the current material each time. This setup does not schedule meetings, connect your calendar, or run automatically.

Customize the job without making it vague

Change the saved instructions when a requirement should apply to every meeting. Keep one-off facts, such as this week's budget or tomorrow's attendees, in the invocation or source files.

For example:

• Client meetings: focus on scope, approvals, deadlines, and unresolved dependencies.

• Team check-ins: focus on blockers, owners, and decisions that unblock work.

• Interview preparation: focus on the role, evidence from your experience, and questions for the interviewer.

If you want shorter briefs, add a standing word limit. If suggestions are hard to verify, require a filename alongside every factual claim. Keep the five output headings until you have a reason to change them.

To update the agent, ask the main Claude Code session to revise meeting-prep.md and show you the changes. Review the tool list again if the change affects what the agent is allowed to do.

The context, priorities, and rules guide provides more examples of making an assistant's instructions specific.

Troubleshooting

Claude cannot find meeting-prep

Check the filename, the personal agents folder, and the name: meeting-prep header. If you just created your first agents folder, restart Claude Code and try again. A project-level agent with the same name can override the personal version; check for a duplicate.

It cannot read my notes

Confirm the path from your current working folder, or provide the full path. For the first test, use the plain-text sample above. If a source format cannot be read, provide an accessible text export and check that the export contains the relevant details.

It invents a deadline or decision

Ask which passage supports that claim. If none does, require it to mark the item unknown or turn it into a question. Revise the saved instruction if the problem repeats.

It offers to edit files or send something

Check that the task actually ran through meeting-prep and inspect the saved tools list. Keep only the three reading tools in this setup. The main session has its own capabilities, so distinguish an offer from the main assistant from a subagent action.

It still gives generic advice

Give it a meeting objective and the latest source material. “Prepare me for a meeting” leaves the job open-ended; a named agenda plus the decision you need to reach makes the result easier to judge.

Your first reusable specialist

Start with one meeting, one notes file, and one clear job. Once the brief reliably identifies real decisions and useful questions, keep the instructions and swap in fresh material for the next meeting.

The setup prompt is the AGENT resource promised in the video. Save this guide so you can reuse it when building your next specialist.