Stream Claude Code's hidden output (thinking, tool calls, subagents) to a separate terminal in real-time.
Note: This is a Rust port of the Go version. The binary is named
claude-esp-rsto allow running both versions side-by-side.
When using Claude Code interactively, tool outputs and thinking are collapsed by default and require pressing Ctrl+O to toggle visibility. This tool lets you watch all that output in a separate terminal with a nice TUI, without interrupting your main Claude Code session.
- Multi-session support - Watch all active Claude sessions simultaneously
- Hierarchical tree view - Sessions with nested Main/Agent nodes
- Real-time streaming - See thinking, tool calls, and outputs as they happen
- Subagent tracking - Automatically discovers and displays subagent activity
- Background task visibility - See background tasks (⏳/✓) under spawning agent
- Filtering - Toggle visibility of thinking, tools, outputs per session/agent
- Auto-scroll - Follows new output, or scroll freely through history
- Rust 1.74 or later
# Install from crates.io
cargo install claude-esp
# Or clone and build from source
git clone https://github.com/phiat/claude-esp-rs.git
cd claude-esp-rs
cargo build --release
# Optional: install to PATH
cp target/release/claude-esp-rs ~/.local/bin/Download pre-built binaries from the Releases page. Available for Linux (amd64, arm64), macOS (amd64, arm64), and Windows (amd64).
# In your main terminal: run Claude Code as normal
claude
# In a second terminal/tmux pane: run the watcher
claude-esp-rs| Option | Description |
|---|---|
-s <ID> |
Watch a specific session by ID |
-n
| Start from newest (skip history, live only) |
-l |
List recent sessions |
-a |
List active sessions (modified in last 5 min) |
-p <ms> |
Poll interval in ms (fallback mode only, default 500) |
-V |
Show version |
-h |
Show help |
| Variable | Description |
|---|---|
CLAUDE_HOME |
Override Claude config directory (default: ~/.claude) |
# Watch all active sessions
claude-esp-rs
# Skip history, only show new output
claude-esp-rs -n
# List active sessions
claude-esp-rs -a
# Watch a specific session
claude-esp-rs -s 0b773376
# Faster poll interval (200ms)
claude-esp-rs -p 200
# List recent sessions
claude-esp-rs -l| Key | Action |
|---|---|
t |
Toggle thinking visibility |
i |
Toggle tool input visibility |
o |
Toggle tool output visibility |
a |
Toggle auto-scroll |
h |
Hide/show tree pane |
A |
Toggle auto-discovery of new sessions |
tab |
Switch focus between tree and stream |
j/k/↑/↓ |
Navigate tree or scroll stream |
space/enter |
Toggle item, or load background task output |
x/d |
Remove selected session from tree |
g/G |
Go to top/bottom of stream |
q/Ctrl+c |
Quit |
Claude Code stores conversation transcripts as JSONL files in:
~/.claude/projects/<project-path>/<session-id>.jsonl
Subagents are stored in:
~/.claude/projects/<project-path>/<session-id>/subagents/agent-<id>.jsonl
Background task outputs are stored in:
~/.claude/projects/<project-path>/<session-id>/tool-results/toolu_*.txt
The watcher:
- Discovers active sessions (modified in last 5 minutes)
- Uses OS-native filesystem notifications (notify) to detect file changes in real-time (inotify on Linux, kqueue/FSEvents on macOS)
- Falls back to polling (configurable with
-p) on filesystems that don't support notifications (NFS, some cross-FS WSL2 setups) - Debounces rapid writes (50ms window) to efficiently handle burst output
- Parses JSON lines and extracts thinking/tool_use/tool_result
- Discovers background tasks and correlates them with spawning agents
- Renders them in a TUI with tree navigation and filtering
Recommended tmux layout:
# Create a new tmux session with two panes
tmux new-session -s claude \; \
split-window -h \; \
send-keys 'claude-esp-rs' C-m \; \
select-pane -L \; \
send-keys 'claude' C-mOr add to your .tmux.conf:
bind-key C-c new-window -n claude \; \
send-keys 'claude' C-m \; \
split-window -h \; \
send-keys 'claude-esp-rs' C-m \; \
select-pane -L
Then press prefix + Ctrl+C to open a Claude Code workspace.
claude-esp-rs/
├── Cargo.toml
├── src/
│ ├── main.rs # CLI entry point
│ ├── lib.rs # Library exports
│ ├── types.rs # Data structures
│ ├── parser.rs # JSONL parsing
│ ├── watcher.rs # File monitoring
│ └── tui/
│ ├── mod.rs # Ratatui main app
│ ├── tree.rs # Session/agent tree view
│ ├── stream.rs # Scrollable output stream
│ └── styles.rs # Colors and styling
└── tests/
└── integration_test.rs
Built with Ratatui and Tokio. Issue tracking was done with beads.
# Run tests
cargo test
# Build release
cargo build --release
# Check formatting
cargo fmt --check
# Lint
cargo clippyMIT