Discord MCP Server #

mcp-discord is an optional MCP server included with the release archive. It gives an agent direct Discord REST capabilities such as reading messages, listing channels, sending messages, creating threads, downloading attachments, and adding reactions.

It is not required for normal bot replies. Ordinary agent final answers should be returned to the bot, which handles redaction, splitting, and delivery.

Build or Locate the Binary #

Release archives include mcp-discord. Source builds can create it with:

go build -o mcp-discord-server ./cmd/mcp-discord

Use one binary name consistently in the catalog command. Deployed environments often use mcp-discord-server next to the main bot binary.

Install Steering Guidance #

The repository includes .kiro/steering/discord-mcp.md. Install it globally only when you want Kiro sessions outside this bot to understand the Discord MCP tools too:

mkdir -p ~/.kiro/steering
cp .kiro/steering/discord-mcp.md ~/.kiro/steering/discord-mcp.md

For bot-managed runtime sessions, MCP visibility is still controlled by channel policy.

Register in the MCP Catalog #

Add an entry to ~/.kiro/settings/mcp.json or the file pointed to by KIRO_MCP_CONFIG:

{
  "mcpServers": {
    "mcp-discord": {
      "command": "sh",
      "args": [
        "-c",
        "set -a && . /absolute/path/to/.env && exec /absolute/path/to/mcp-discord-server"
      ],
      "env": {}
    }
  }
}

For multi-bot local development, make sure the .env is the same bot identity you are testing. If the visible Discord bot is M5Bot but the catalog command loads ChunBot's token, Discord permission changes for M5Bot will not fix MCP 403 Missing Access errors.

Add Defense-in-depth Guards #

Set env guards in the loaded .env or catalog environment:

MCP_DISCORD_ALLOWED_GUILDS=123456789012345678
MCP_DISCORD_ALLOWED_CHANNELS=234567890123456789,345678901234567890
MCP_DISCORD_DOWNLOAD_DIR=/tmp/kiro-discord-mcp
MCP_DISCORD_READ_ONLY=false
MCP_DISCORD_ALLOWED_WRITE_TOOLS=discord_send_message,discord_reply_message,discord_resolve_mentions
MCP_DISCORD_ALLOW_DESTRUCTIVE=false
MCP_DISCORD_MEMBER_SCAN_LIMIT=5000

Empty allowlists preserve legacy unrestricted behavior. Production deployments should prefer explicit guild/channel allowlists when the bot has broad Discord access.

Enable Per Channel #

Registration adds the server to the catalog. The bot's default bot-tools setup automatically enables only discord_resolve_mentions for mcp-discord when this catalog entry is present, matching the default-on bot-native image URL egress behavior while keeping broader Discord REST tools closed.

For additional tools in Discord:

Run /mcp status to confirm mcp-discord appears.
Run /mcp manage.
Scan the server.
Enable only the extra tools the channel needs.
Let the bot restart active agents so the new policy is injected on the next session.

Common Tool Groups #

Group	Examples	Risk
Read	`discord_read_messages`, `discord_search_messages`, `discord_channel_info`	Can expose channel content to the agent
Mention resolver	`discord_resolve_mentions`	Resolves requested names with fresh Discord member lookup, grants only exact/unique matches for the active bot task, and returns safe `[[discord:user:...]]` placeholders
Write	`discord_send_message`, `discord_reply_message`, `discord_send_embed`	Sends visible Discord messages
Thread	`discord_create_thread`, `discord_list_threads`	Creates or inspects conversation surfaces
Management	`discord_edit_message`, `discord_pin_message`, `discord_edit_channel_topic`	Higher operational risk
Attachment	`discord_download_attachment`	Needs download directory controls

Prefer read-only access first, then add non-destructive write tools only where they are part of the workflow.

When a user asks to tag or notify a named person who was not already mentioned in the current prompt, prefer discord_resolve_mentions over discord_list_members. It performs fresh REST member search before bounded scan/cache fallback, writes resolved refs into the current bot target state, and returns placeholders the agent can use in the final answer. Ambiguous or missing names must be clarified instead of guessed. Increase MCP_DISCORD_MEMBER_SCAN_LIMIT only when exact names routinely miss because the guild is larger than the default bounded scan.