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Send cross-channel messages

Task​

Configure Ethos so a personality talking to you in Telegram can post a message into a Slack channel — and vice versa — via the send_message tool.

Result​

When you DM your Telegram bot:

Send "build green ✓" to slack channel C0123ABC

…the agent calls send_message, the gateway routes through the Slack adapter, and your Slack channel shows the message from your Slack bot user.

Prereqs​

  • ethos gateway working end-to-end on at least one channel (Telegram or Slack already replying to messages).
  • Both adapters configured in ~/.ethos/config.yaml — see Multi-bot Telegram and the Slack platform guide.
  • A personality bound to your Telegram bot (e.g. engineer) that you can edit.

Steps​

1. Add send_message to the personality toolset​

send_message is not in any bundled personality's default toolset — operators opt in explicitly. Edit ~/.ethos/personalities/<id>/toolset.yaml (or the bundled personality file under extensions/personalities/data/<id>/toolset.yaml for a framework-default change):

- terminal
- read_file
# ... existing tools ...
- send_message

The bundled engineer already has it.

2. Get the target Slack channel ID​

send_message's target field takes the channel ID (e.g. C0123ABC), not the channel name (#engineers). Two ways to find it:

  • Channel URL. Open the channel in Slack web/desktop. URL ends in /C0123ABC.
  • Right-click → Copy link. The link contains the ID.

If you want the agent to DM a Slack user instead, the user ID format is U0123ABC (visible under Profile → ⋮ → Copy member ID).

3. Invite your Slack bot to the channel​

The bot can't post to a channel it's not a member of. From the destination channel in Slack:

/invite @YourBotName

If the bot is missing chat:write scope you'll get an error here — see use-as-mcp-server or receive-files-via-slack for the OAuth scope setup.

4. Write the allowlist​

Create or edit ~/.ethos/messaging.json:

{
  "engineer": ["slack:C0123ABC"]
}

Replace engineer with whichever personality you wired in step 1, and C0123ABC with the channel ID from step 2.

For testing, the universal wildcard works:

{
  "engineer": ["*"]
}

— allows the personality to send to any platform/target. Lock down to specific entries before production.

5. Restart the gateway​

messaging.json is read once at boot. After every edit:

# Stop the running gateway with Ctrl-C, then:
ethos gateway

The boot banner prints one line per active adapter — confirm both telegram and slack are listed.

6. Test from Telegram​

DM your Telegram bot:

Use the send_message tool to post "hello kevin" to slack channel C0123ABC.

Explicit phrasing helps — the model occasionally hesitates with softer prompts ("can you send …"). The "use the send_message tool" prefix removes ambiguity.

Verify​

Three surfaces confirm success simultaneously:

  • Gateway stdout prints tool_start: send_message followed by tool_end: send_message (Xms) ok.
  • Telegram reply from the engineer narrates the action — "Posted to slack:C0123ABC."
  • Slack channel shows a new message from the bot user with the body you specified.

If only one or two of the three appear, the discrepancy points at the failure layer (see Troubleshoot).

Examples​

Slack → Telegram​

Same setup in reverse. The engineer personality has send_message in its toolset; the allowlist includes a Telegram target:

{
  "engineer": ["slack:C0123ABC", "telegram:-1001234567890"]
}

@mention the bot in Slack:

@Kevin send "deploy starting" to telegram chat -1001234567890

Tool call routes through the Telegram adapter — your Telegram chat shows the message.

Cron-triggered fan-out​

Set up a cron job that fires a personality with this prompt:

Post "standup in 5 minutes" to slack:C0STANDUP and to telegram:-1001234567890.

Allowlist must contain both targets. The agent calls send_message twice — outbound dedup is per-target, so the same body to two different targets both go through.

Multi-bot routing​

If your ~/.ethos/config.yaml has multiple Slack apps (slack.apps.0.*, slack.apps.1.*), the gateway uses the first adapter for each platform when send_message dispatches. Different Slack workspaces aren't selectable today — track MessagingSendFn's botKey parameter for the in-flight extension.

Troubleshoot​

"Gateway not active — send_message requires gateway mode" — You're running ethos chat, not ethos gateway. The tool only routes through the Gateway's adapter registry. Switch.

"No adapter registered for platform 'slack'" — Slack isn't configured. Check ~/.ethos/config.yaml has at least one slack.apps.0.* block, gateway boot didn't error, and slack.apps.0.botToken / appToken / signingSecret resolve through ${secrets:...} correctly.

"Target 'slack:C0123ABC' is not in the personality's allowed messaging targets. Allowed: none" — messaging.json doesn't list this target for this personality. Add it, or use "*" for testing. Don't forget the gateway restart.

Engineer narrates a polite refusal without calling the tool — The LLM is hallucinating. Prompt explicitly: "Use the send_message tool to ...". If it still refuses, ask: "What tools do you have available?" — the reply should list send_message. If absent, the toolset.yaml edit didn't propagate; verify the file and restart the gateway.

"Adapter send failed: not_in_channel" — Slack rejected because the bot isn't in the channel. From the channel in Slack: /invite @YourBotName.

Send works but the message is dropped silently within 30s — Outbound dedup. The same (platform, target, body) sent twice within 30 seconds is suppressed. Vary the body or wait past the TTL.

Engineer says "I don't have permission to send messages" even after the toolset has send_message — The tool description used to say "The personality must have messaging.send capability", which caused this exact refusal. The description was updated; if you see this on an older build, restart the gateway after pulling.

See also​