create-theme

A guide for creating and changing Sidecar color themes, including base themes, color overrides, borders, tabs, project-specific settings, and registered community themes.

In plain words
What is it for?
Use it to select a base theme, adjust colors, style tabs or gradient borders, set themes per project, or register a theme programmatically.
Why use it?
It explains where theme settings live and how the available visual parts fit together, which reduces guesswork when changing the interface.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/marcus/sidecar/create-theme
Any agent
npx skills add marcus/sidecar --skill create-theme
Clone the repo
git clone --depth 1 https://github.com/marcus/sidecar

Made for: Claude Code, Codex.

Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,860 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00074 $0.03860
Opus 5 $0.00037 $0.01930
Sonnet 5 $0.00015 $0.00772
Haiku 4.5 $0.00007 $0.00386

Measured yesterday against content hash 039d90646ae8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 yesterday.

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.

.claude/skills/create-theme/SKILL.md · 342 lines

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"
      }
    }
  }
}

Read the full file on GitHub · 342 lines

Changes

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.

  1. yesterday First seen · 342 lines · 74 tokens per session scan A 039d90646ae8

Subscribe to this mod's changes

create-theme is a skill published in the GitHub repository marcus/sidecar (1,049 stars, last pushed yesterday), licensed MIT. It adds 74 tokens to every session and 3,860 once invoked, about $0.0004 per session on Opus 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.

Related

Other skills, from other repositories

intake

The planning front-door. Captures feature ideas and bugs as graded rows in the root INTAKE.md ledger. Use it when the user says "log an idea", "capture a bug", "add to the backlog", "note this down", "track this feature", or invokes /intake. Owns the requirements interview — fleshes out thin ideas, proactively…

ndisisnd/msg · 239 tokens

merge

The ship gate — the only skill that merges. --staging merges the feature→staging PR on green CI, deploys, verifies, emits a human test script and stamps the staging sign-off on approval. --production ships the double-confirmed release to main and deploys production. Never self-certifies staging; nothing reaches main…

ndisisnd/msg · 94 tokens

pre-merge

The CI gate. Takes a feature branch from "eng says done" to "PR open against staging with green checks". Runs the project's preflight-resolved pipeline from devkit/policy.json components[]: sync → parallel correctness + security waves → coverage → regression tail → security/migration → PRD-consistency → open PR. Emits…

ndisisnd/msg · 101 tokens

msg

Root menu for msg skills, plus harness modes. --init is the one-time project bootstrap — use it when the user says "initialise project", "bootstrap repo", "set up the framework", "start a new project", or asks to set up project structure in an empty repo. Other modes: --init-staging (add a staging branch), --update…

ndisisnd/msg · 162 tokens

lorekeeper-reconcile

Reconcile and fact-check Lorekeeper memories against source materials, existing documentation, and internal consistency. Use when (1) the user provides reference materials to verify against, (2) the user requests a general knowledge audit, or (3) the user wants to verify specific topics. Updates memory scores and…

Jessinra/Lorekeeper · 72 tokens

backlog-management

Lorekeeper backlog management — ticket lifecycle, numbering, scripts, and conventions. Load this when filing tickets, moving ticket states, checking what's ready to work on, or onboarding to the project workflow.

Jessinra/Lorekeeper · 43 tokens