stail is a read-only command-line tool for Slack. It lets you stream channel messages in real time — like tail -f — or export full channel history to JSON.

It is designed as a companion to scat: scat posts to Slack, stail reads from it.

• Real-time streaming — stail tail -f connects via Slack Socket Mode (WebSocket) and prints new messages as they arrive.
• Historical tail — stail tail -n 50 shows the last N messages and exits.
• Timestamp-based tail — stail tail --since 2024-01-15T10:00:00Z streams all messages from an absolute point in time (Slack ts or RFC3339).
• Channel export — stail export downloads full channel history as a structured JSON file compatible with scat's export log format.
• Channel listing — stail channel list shows all accessible channels with their IDs.
• Profile management — Multiple named profiles, each with its own token and default channel.
• Server mode — Configure entirely via environment variables for container / CI deployments.
• Cross-platform — Single static binary for macOS, Linux, and Windows.

Download the latest binary for your platform from the Releases page.

Or build from source:

make build
# Binary: ./dist/stail

For a detailed step-by-step walkthrough, see the Slack Setup Guide.

stail requires two tokens from your Slack App:

Bot Token scopes (OAuth & Permissions):

• channels:history — read public channel messages
• channels:read — list public channels
• groups:history — read private channel messages (if needed)
• groups:read — list private channels (if needed)
• users:read — resolve user display names

App-Level Token (required for tail -f only):

1. Go to your app's Basic Information page.
2. Under App-Level Tokens, click Generate Token and Scopes.
3. Add the connections:write scope.
4. Copy the xapp-... token.

Enable Socket Mode in your app settings.

stail config init

Creates ~/.config/stail/config.json with 0600 permissions.

stail profile add my-workspace --provider slack --channel "#general"
# You will be prompted to enter the Bot Token and App Token securely.

stail profile use my-workspace

# Show last 10 messages from the default channel
stail tail

# Show last 50 messages from a specific channel
stail tail -c "#general" -n 50

# Show all messages since an absolute timestamp (RFC3339 or Slack ts)
stail tail -c "#general" --since 2024-01-15T10:00:00Z
stail tail -c "#general" --since 1742378100.123456

# Show the newest 5 messages since a given timestamp
stail tail -c "#general" --since 2024-01-15T10:00:00Z -n 5

# Follow mode: stream new messages in real time (requires app_token)
stail tail -c "#general" -f

# Follow mode with JSON output (JSONL, one object per line)
stail tail -c "#general" -f --format json

# Save attached files to a directory while tailing
stail tail -c "#general" -f --save-dir ./downloads

Attached files are shown inline in text mode:

2026-03-19 10:44:11  #general  @alice  See attached [添付: report.pdf]
2026-03-19 10:44:12  #general  @bob    [添付: photo.png]

Exports the full history as a JSON document matching scat's export log schema:

# Export to stdout
stail export -c "#general"

# Export to a file
stail export -c "#general" --output archive.json

# Export a specific time range (RFC3339 or Slack ts)
stail export -c "#general" \
  --start 2025-01-01T00:00:00Z \
  --end   2025-02-01T00:00:00Z

# Export and save all attached files
stail export -c "#general" --output archive.json --save-dir ./attachments

Note: export fetches the full channel history into memory before writing. For very large channels, use --start / --end to export in smaller time ranges. Both flags accept RFC3339 (e.g. 2025-01-01T00:00:00Z) or Slack ts format (e.g. 1742378100.000000).

Export JSON schema (compatible with scat and scli — see docs/EXPORT_FORMAT.md for full specification):

{
  "export_timestamp": "2026-03-19T10:00:00Z",
  "channel_name": "#general",
  "messages": [
    {
      "user_id": "U12345ABC",
      "user_name": "alice",
      "post_type": "user",
      "timestamp": "2026-03-19T09:55:00Z",
      "timestamp_unix": "1742378100.000000",
      "text": "Hello!",
      "files": [],
      "is_reply": false
    }
  ]
}

post_type is either "user" or "bot". Legacy attachments and Block Kit blocks are included when present (omitted when empty).

stail channel list
stail channel list --json

stail profile list              # list all profiles
stail profile use my-workspace  # switch active profile
stail profile add staging       # add a new profile (prompts for tokens)
stail profile set channel "#ops"
stail profile set token         # update token (secure prompt)
stail profile set app_token     # update app token (secure prompt)
stail profile remove staging

stail config init   # create default config file

stail caches the channel list for the active profile to avoid repeated API calls on every invocation. The cache is stored in ~/.config/stail/cache/<profile>/ and expires after one hour.

stail cache clear   # delete cached data for the active profile

For container and CI deployments, set STAIL_MODE=server to read all configuration from environment variables — no config file needed.

export STAIL_MODE=server
export STAIL_PROVIDER=slack
export STAIL_TOKEN=xoxb-xxxxxxxxxxxx
export STAIL_CHANNEL="#alerts"

stail tail -n 20

env:
  - name: STAIL_MODE
    value: "server"
  - name: STAIL_PROVIDER
    value: "slack"
  - name: STAIL_CHANNEL
    value: "#alerts"
  - name: STAIL_TOKEN
    valueFrom:
      secretKeyRef:
        name: slack-credentials
        key: bot-token

The following commands are not available in server mode:

• --config flag
• --profile flag
• All profile subcommands
• config init

# Current OS/Arch
make build

# All platforms (macOS amd64/arm64, Linux amd64/arm64, Windows amd64)
make build-all

# Run tests
make test

# Tidy dependencies
make tidy

Note (sandbox / restricted environments): If the default Go cache paths are not writable, set GOCACHE and GOMODCACHE explicitly:

GOCACHE=/tmp/go-cache GOMODCACHE=/path/to/gopath/pkg/mod make build

MIT License — see LICENSE.