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
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/marcus/sidecarnpx agentmods add skills/marcus/sidecar/create-themeWrote 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/create-theme)<a href="https://agentmods.dev/skills/marcus/sidecar/create-theme"><img src="https://agentmods.dev/badge/skills/marcus/sidecar/create-theme/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/create-theme"><img src="https://agentmods.dev/badge/skills/marcus/sidecar/create-theme.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Rogue Agent · line 4 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
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 | $0.00074 | $0.03860 |
| Opus 5.5 | $0.00030 | $0.01544 |
| Sonnet 5.5 | $0.00015 | $0.00772 |
| Haiku 4.5 | $0.00007 | $0.00386 |
Grade A, and why
create-theme 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 — 342 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Create Theme
Configuration Location
Themes are configured in ~/.config/sidecar/config.json:
{
"ui": {
"showFooter": true,
"showClock": true,
"nerdFontsEnabled": false,
"theme": {
"name": "default",
"overrides": {
"primary": "#FF5500",
"success": "#00FF00"
}
}
}
}
Available Base Themes
Sidecar ships with 21 modern, contrast-compliant themes designed around a 7-step neutral ramp and single signature chrome accent:
- sidecar-modern - Modern default with signature gold accent (
#c0982f) and dark neutral ramp - catppuccin-mocha - Soothing lavender/blue (
#89b4fa) with dark mantle - tokyonight-storm - Tokyo neon night blue (
#7aa2f7) - gruvbox-dark - Retro warm gold (
#fabd2f) & aqua (#8ec07c) - dracula - Refined vampire violet (
#bd93f9) - nord - Arctic frost cyan (
#88c0d0) - atom-one-dark - Balanced editor cyan/blue (
#61afef) - kanagawa-wave - Woodblock print wave blue (
#7e9cd8) - rose-pine - Soho rose (
#eb6f92) & pine cyan (#9ccfd8) - everforest-dark - Earthy forest green (
#a7c080) & warm amber (#dbbc7f) - solarized-dark - Precision amber/yellow (
#b58900) & cyan (#2aa198) - monokai-pro - Crisp gold (
#ffd866) & green (#a6e22e) - night-owl - Deep navy blue (
#82aaff) - ayu-mirage - Warm sunset gold (
#6dcbfa) on slate - github-dark - Crisp GitHub cobalt (
#58a6ff) - synthwave - 80s retrowave fuchsia (
#ff77ff) - cobalt2 - High-contrast Wes Bos cobalt yellow (
#ffe50a) - horizon - Cyberpunk apricot/red (
#ed718e) - shades-of-purple - High-contrast magenta/violet (
#ff77ff) - spacegray-eighties - Muted classic warm gray & blue (
#7ba1cf) - zenburn - Low-contrast soft green (
#90cbae)
Creating a Custom Theme
Method 1: Override Specific Colors
Start from a base theme and override specific colors:
{
"ui": {
"theme": {
"name": "default",
"overrides": {
"primary": "#E91E63",
"success": "#4CAF50",
"error": "#F44336",
"syntaxTheme": "github"
}
}
}
}
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 · 342 lines · 74 tokens per session scan A 039d90646ae8
create-theme is a skill published in the GitHub repository marcus/sidecar (1,091 stars, last pushed 11d ago), licensed MIT. It adds 74 tokens to every session and 3,860 once invoked, about $0.0003 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
review-implementation-design
Implementation review Design axis - live-runs visible UI quality and originality.
design
Collaborative design document creation from research findings.
frontend-design
Guidance for distinctive, intentional visual design when building new UI or reshaping an existing one. Helps with aesthetic direction, typography, and making choices that don't read as templated defaults.
vercel-composition-patterns
React composition patterns that scale. Use when refactoring components with boolean prop proliferation, building flexible component libraries, or designing reusable APIs. Triggers on tasks involving compound components, render props, context providers, or component architecture. Includes React 19 API changes.
principle-redesign-from-first-principles
Apply when integrating a new requirement into an existing design.
mcp-host-styling-integration
Integrates MCP App UI with host theming system. Applies host CSS variables, handles onhostcontextchanged, safe area insets, display mode detection, and fullscreen configuration.