Sidecar is a terminal-based workspace for running AI coding agents alongside file trees, task issues, Git diffs, and Jira or GitHub resources in split panes. Developers use it to monitor agent sessions, inspect files and changes, manage workspaces, and handle tasks without leaving one shell. The catalogue entries extend or guide coding-agent workflows used with Sidecar.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add marcus/sidecar --skill shell-integrationgit clone --depth 1 https://github.com/marcus/sidecarWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/marcus/sidecar/shell-integration)<a href="https://agentmods.dev/skills/marcus/sidecar/shell-integration"><img src="https://agentmods.dev/badge/skills/marcus/sidecar/shell-integration/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/marcus/sidecar/shell-integration"><img src="https://agentmods.dev/badge/skills/marcus/sidecar/shell-integration.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00062 | $0.03288 |
| Opus 5.5 | $0.00025 | $0.01315 |
| Sonnet 5.5 | $0.00012 | $0.00658 |
| Haiku 4.5 | $0.00006 | $0.00329 |
Grade A, and why
shell-integration scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 360 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Shell Integration
Sidecar's interactive shell allows users to type directly into tmux sessions
from within the TUI. Tmux remains the PTY backend. Sidecar renders ordered
control-mode bytes through the shared tty.Model, whose VT behavior is behind
the screenmodel adapter rather than implemented in plugin code.
Package Structure
internal/tty/ # Shared tmux terminal abstraction
tty.go # Core Model and State types
keymap.go # Bubble Tea -> tmux key translation
messages.go # Owner/target/generation-scoped messages
session.go # tmux operations (send-keys, capture-pane, resize)
scheduler.go # Keyed fallback-poll generation ownership
control_*.go # Session-keyed tmux -C transport and manager
capture_range.go # Atomic bounded history capture
cursor.go # Cursor positioning helpers
paste.go # Paste handling (clipboard, bracketed paste)
terminal_mode.go # Capture-fallback mode recovery
output_buffer.go # Absolute, bounded live/history buffer
editor_session.go # Shared inline-editor tmux lifecycle
internal/plugins/workspace/
interactive.go # Workspace-specific interactive mode logic
interactive_selection.go # Text selection in interactive mode
terminal_viewport.go # Pure shared terminal viewport renderer
terminal_control.go # Workspace target/layout policy for tty.Model
terminal_history.go # Lazy absolute scrollback loading
terminal_search.go # Loaded-history search
terminal_links.go # Safe URL/path detection and activation
native_terminal.go # Native cursor and contextual mouse mode
view_preview.go # Agent/shell preview composition
mouse.go # Scroll handling
types.go # InteractiveState type
internal/plugins/filebrowser/
inline_edit.go # Inline editor mode using tty.Model
handlers.go # Message handling for inline edit
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago Changed c06f6486cf17
- 1mo ago First seen · 360 lines · 62 tokens per session scan A db47c1a87bbc
shell-integration is a skill published in the GitHub repository marcus/sidecar (1,091 stars, last pushed 11d ago), licensed MIT. It adds 62 tokens to every session and 3,288 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other skills, from other repositories
revise-roadmap
Revise an implementation roadmap based on critic feedback.
build-knowledge-base
Build or update a persistent repo knowledge base graph.
research-codebase
Document codebase as-is through comprehensive research.
validate-phase-plan-structural
Per-phase plan structural validation gate - evaluates conformance to the concise vertical-slice phase-plan format.
implement
Execute an approved phase plan with TDD, dependency-aware task fan-out, required evidence, and a strict iteration handoff.
review-comments
Execute a feature-level review-comments cycle — aggregate unaddressed PR comments across every Feature.Repos PR, address or dismiss each one, and emit the standard handoff.