Mattermost Test Data & MCP Usage

Populate a Mattermost server with realistic test data and interact with it using the connected Mattermost MCP tools.

Available MCP Tools

Write Operations

Read Operations

Test Data Creation Workflow

Follow this order to avoid missing dependencies:

Step 1: Gather Requirements from User

Ask the user what kind of environment they want. If they don't specify, offer a default scenario. Key questions:

• Theme: What kind of team? (engineering, sales, support, devops, etc.)
• Scale: How many users, channels, and messages?
• Conversation topics: Any specific scenarios to demonstrate?
• Realism level: Casual startup vs formal enterprise tone?

Merge user instructions with the defaults below. User instructions always take priority.

Step 2: Create the Team

create_team:
  name: url-friendly-name (lowercase, hyphens)
  display_name: Human Readable Name
  type: O (open) or I (invite-only)
  description: Brief team description

Save the returned team_id for subsequent calls.

Step 3: Create Users

Create users with realistic, diverse profiles. For each user, define a persona that guides their communication style throughout all conversations.

Guidelines:

• Use first.last format for usernames
• Use realistic email addresses (e.g., first.last@example.com)
• Use password Testpassword1! for all test users (simple, meets complexity requirements)
• Give each user a distinct role and communication style
• Vary seniority levels (lead, senior, mid, junior, etc.)

Save each returned user_id.

Persona template (track internally, do not post):

Name: [Full Name]
Username: [first.last]
Role: [Job title]
Style: [Communication traits - e.g., concise and technical, friendly and verbose, asks lots of questions]
Expertise: [Domain strengths]

Step 4: Add Users to Team

Call add_user_to_team for each user with the team_id from Step 2.

Step 5: Create Channels

Create channels appropriate for the team theme. Always include:

• A general channel for announcements and broad discussion
• A random channel for casual/off-topic conversation
• 2-4 topic-specific channels matching the team's domain

For each channel, provide a meaningful purpose and header.

Save each returned channel_id.

Step 6: Add Users to Channels

Call add_user_to_channel for each user+channel combination. Not every user needs to be in every channel - match membership to roles.

Step 7: Create Conversations

This is the most important step. Use create_post_as_user to post as each user with their username and password.

Conversation Quality Guidelines

Message variety:

• Mix short responses ("Sounds good!", "On it.") with detailed technical messages
• Include markdown formatting where natural (code blocks, bullet lists, bold)
• Some messages should reference external links or tools
• Vary message length by persona (seniors write concisely, juniors explain more)

Thread usage:

• Use root_id to create threaded replies for detailed discussions
• Not every message needs a thread - quick acknowledgments stay in main channel
• Threads should have 2-5 replies typically, occasionally more for complex topics

Persona consistency:

• The team lead coordinates, makes decisions, celebrates wins
• Senior engineers give concise technical guidance
• Junior engineers ask questions, share what they learned
• Each person has a distinct voice

Natural flow:

• Conversations should reference each other implicitly ("as we discussed in #incidents")
• Include realistic work artifacts (deployment commands, config snippets, monitoring queries)
• Show collaboration: someone asks a question, others help, problem gets resolved

Conversation Templates

For each channel, create 2-4 distinct conversation threads. Example patterns:

Problem-solving thread:

1. Someone reports an issue
2. Others investigate and discuss
3. Solution is found and confirmed
4. Brief wrap-up or action items

Coordination thread:

1. Someone proposes a plan or schedule
2. Others confirm availability or raise concerns
3. Plan is finalized

Knowledge-sharing thread:

1. Someone shares an article, tool, or technique
2. Brief discussion about applicability
3. Maybe a follow-up action

Casual thread (for #random):

1. Light topic (weekend, conference, food)
2. A few friendly replies
3. Naturally fizzles out

Tips for Realistic Data

• Don't over-emoji. Real engineers use them sparingly. One or two per conversation, not every message.
• Include imperfections. Occasional typos, self-corrections ("wait, I meant..."), or "nvm, found it" messages.
• Reference real tools. Mention Grafana, Terraform, Kubernetes, Jenkins, GitHub, etc. by name.
• Show team dynamics. The lead praises good work. The junior asks for help. The senior mentors casually.
• Keep it proportional. 3-5 messages per simple thread, 6-10 for complex discussions. Don't create 50-message threads.

Reading and Searching Data

Find existing data

search_users: term="john"            # Find users by name/email
get_team_info: team_display_name="Engineering"  # Find team by name
get_channel_info: channel_display_name="General" # Find channel by name

Read conversations

read_channel: channel_id="...", limit=50        # Recent messages
read_channel: channel_id="...", since="2024-01-01T00:00:00Z"  # Since timestamp
read_post: post_id="...", include_thread=true   # Full thread
search_posts: query="deployment", team_id="..." # Search by keyword

Inspect membership

get_team_members: team_id="...", limit=50, page=0
get_channel_members: channel_id="...", limit=50, page=0

Common Pitfalls

• Channel name vs display_name: name must be URL-friendly (lowercase, hyphens, no spaces). display_name is what users see.
• Team type: Use O for open, I for invite-only. Most test scenarios want O.
• Channel type: Use O for public, P for private.
• Post ordering: Posts appear in creation order. Create them in the order you want them to appear.
• Thread replies: Set root_id to the parent post's ID. The channel_id must match the parent post's channel.
• User passwords: When using create_post_as_user, you need the password you set during user creation. Keep it consistent.
• IDs are 26 characters: All Mattermost IDs (team, channel, user, post) are exactly 26 alphanumeric characters.

Example: Minimal Quick Setup

For a fast demo with minimal data:

1. Create team "demo-team"
2. Create 3 users (lead, senior, junior)
3. Add users to team
4. Create 2 channels (general, project)
5. Add users to channels
6. Create 5-8 messages per channel with 1-2 threaded discussions

This produces a believable workspace in ~30 tool calls.