Live Tail

Stream events, logs, and syslog messages as they flow through Tell’s pipeline. The tail connects to a running Tell server via Unix socket and decodes batches in real time — useful for debugging, monitoring deploys, and verifying that data is flowing correctly.

tell tail

This streams everything. In production, you’ll want filters.

Filtering

Server-side filters are applied before data leaves the server — use these to reduce volume:

# Only events from workspace 1
tell tail --workspace 1

# Only error logs from the HTTP source
tell tail --type log --level error --source http

# 1% sample at max 100 batches/sec
tell tail --sample 0.01 --rate-limit 100

Client-side filters match content after decoding:

# Events matching a glob pattern
tell tail --event "purchase_*"

# Regex match across any string field
tell tail --match "timeout|connection refused"

# Combine: error logs mentioning payments
tell tail --type log --level error --match "payment"

All filter flags are repeatable — --workspace 1 --workspace 2 streams from both.

Output formats

tell tail                          # colored text (default)
tell tail --output json            # one JSON object per event
tell tail --output compact         # single-line summary per event
tell tail --output raw             # raw decoded FlatBuffer data
tell tail --metadata-only          # batch metadata without payload decode

Use --output json for piping into jq or other tools:

tell tail --type event --output json | jq '.event_name'

Replay

Replay the last N batches from the server’s ring buffer on connect:

tell tail --last 50

This is useful for catching up on what just happened without waiting for new data.

Setup

The tail connects to Tell’s tap server via Unix socket. The tap server starts automatically with tell run — no extra configuration needed. The default socket path is derived from your data directory. To connect to a specific socket:

tell tail --socket /tmp/tell-tap.sock

tell tail is available on Unix systems only (macOS, Linux). It requires the tail feature flag at build time, which is included in the default build.

What’s next

CLI commands — full flag reference for tell tail
Pipeline overview — understand what flows through the pipeline
Sources overview — where the data you’re tailing comes from

CLI

AI Integration

Running Tell

Filtering

Output formats

Replay

Setup

What’s next

​Filtering

​Output formats

​Replay

​Setup

​What’s next

Filtering

Output formats

Replay

Setup

What’s next