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 project-switchinggit 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/project-switching)<a href="https://agentmods.dev/skills/marcus/sidecar/project-switching"><img src="https://agentmods.dev/badge/skills/marcus/sidecar/project-switching/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/project-switching"><img src="https://agentmods.dev/badge/skills/marcus/sidecar/project-switching.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 | $0.00057 | $0.01556 |
| Opus 5.5 | $0.00023 | $0.00622 |
| Sonnet 5.5 | $0.00011 | $0.00311 |
| Haiku 4.5 | $0.00006 | $0.00156 |
Grade A, and why
project-switching 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 — 196 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Project Switching
Switch between git repositories without restarting sidecar. Press @ to open the project switcher modal.
Architecture Overview
The project switcher uses the app's declarative modal library (internal/modal/) for rendering and mouse handling.
Key Files
| File | Contents |
|---|---|
internal/app/model.go |
State, init, reset, filter, switch, theme preview |
internal/app/update.go |
Keyboard and mouse handlers |
internal/app/view.go |
Modal building and section rendering |
internal/modal/ |
Modal library (builder, sections, layout) |
internal/config/types.go |
ProjectConfig struct |
internal/config/loader.go |
Config loading with path validation |
Model State
// internal/app/model.go
showProjectSwitcher bool
projectSwitcherCursor int
projectSwitcherScroll int
projectSwitcherInput textinput.Model
projectSwitcherFiltered []config.ProjectConfig
projectSwitcherModal *modal.Modal // Cached modal instance
projectSwitcherModalWidth int // Width for cache invalidation
projectSwitcherMouseHandler *mouse.Handler
Project vs Worktree Switching
- Project Switching (
@): Switch between configured projects fromconfig.json(arbitrary repos) - Worktree Switching (
W): Switch between git worktrees within the current repository
Configuration
Projects are configured in ~/.config/sidecar/config.json:
{
"projects": {
"list": [
{"name": "sidecar", "path": "~/code/sidecar"},
{"name": "td", "path": "~/code/td", "theme": "dark"}
]
}
}
Paths support ~ expansion. Projects can have per-project themes.
Core Flow
Opening (@ key)
case "@":
m.showProjectSwitcher = !m.showProjectSwitcher
if m.showProjectSwitcher {
m.activeContext = "project-switcher"
m.initProjectSwitcher()
} else {
m.resetProjectSwitcher()
m.updateContext()
}
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 First seen · 196 lines · 57 tokens per session scan A 8129a5b306da
project-switching is a skill published in the GitHub repository marcus/sidecar (1,091 stars, last pushed 11d ago), licensed MIT. It adds 57 tokens to every session and 1,556 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
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backlog-management
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lorekeeper-pm
PM workflow for Lorekeeper. Load when managing backlog, filing tickets, reviewing dev work, or planning features. For ticket lifecycle, numbering, and scripts, see backlog-management skill.