bb is an agentic IDE that lets users control, customize, and automate a software-development environment through a desktop app, web app, command-line interface, or HTTP API. Developers use it to run work in observable threads that can be steered or handed off to other agents. Its catalogue add-ons provide skills and instructions for working with bb.
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 get-bb/bb --skill bb-theme-authoringgit clone --depth 1 https://github.com/get-bb/bbWrote 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/get-bb/bb/bb-theme-authoring)<a href="https://agentmods.dev/skills/get-bb/bb/bb-theme-authoring"><img src="https://agentmods.dev/badge/skills/get-bb/bb/bb-theme-authoring/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/get-bb/bb/bb-theme-authoring"><img src="https://agentmods.dev/badge/skills/get-bb/bb/bb-theme-authoring.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 3 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 | $0.00020 | $0.01223 |
| Opus 5.5 | $0.00008 | $0.00489 |
| Sonnet 5.5 | $0.00004 | $0.00245 |
| Haiku 4.5 | $0.00002 | $0.00122 |
Grade A, and why
bb-theme-authoring 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 — 119 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Authoring a bb theme
A bb theme is one CSS file that overrides the app's CSS custom properties. bb discovers custom themes on disk and the Theme Preview panel shows every resolved token, its validation state, and an app mock that repaints as you edit. Work in a split: your agent thread on one side, Theme Preview on the other. Nothing needs a restart.
Theme Preview is visualization and validation only. It never creates, writes,
forks, repairs, or deletes a theme resource. Create and update theme.css from
the separate agent thread; use the existing bb theme commands to locate,
inspect, and activate themes. Validation reports inconsistent or inaccessible
results, but it never changes authored values.
Where themes live
bb theme dir # the custom-theme directory, e.g. ~/.bb/theme
One directory per theme, one file inside it:
<theme dir>/<name>/theme.css
<name> is the theme id: lowercase, letters, digits and dashes, a single path
segment. Create the directory and the file and it is listed immediately — the
Theme Preview dropdown picks it up on its next catalog refresh while the panel
is open, and bb theme list shows it at once.
File shape
Two top-level blocks. Light values in :root, .light, dark values in .dark.
Every declaration is a --token: value; custom property.
:root, .light {
--canvas: #f4f4f4;
--ink: #0a0a0a;
--primary: #2e6f95;
--primary-foreground: #ffffff;
}
.dark {
--canvas: #1a1a1a;
--ink: #dbd8d1;
--primary: #9db6c6;
--primary-foreground: #0a0a0a;
}
You only need to declare what you change; everything else derives from bb's
base theme. The anchors that drive the most are --canvas, --ink,
--primary and --sidebar.
Tokens worth knowing
| group | tokens |
|---|---|
| Surfaces | --canvas --sidebar --card --popover --secondary --muted --surface-recessed-solid --surface-scrim |
| Ink | --ink (body) --foreground --muted-foreground --subtle-foreground --readback-foreground --sidebar-foreground |
| Accent and state | --primary --primary-foreground --file-accent --timeline-accent --surface-selected --state-hover --state-active --sidebar-accent |
| Status | --success --warning --warning-text --destructive --destructive-text --pr-merged --diff-added --diff-removed |
| Lines | --border --border-hairline --border-seam --sidebar-border --input --ring |
| Type | --font-sans --font-mono --font-terminal (declare once in :root) |
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 · +2 lines 083548671188
- 1mo ago Changed · -11 lines · -43 tokens per session 735372d06800
- 1mo ago First seen · 128 lines · 63 tokens per session scan A be1a9f98ab8a
bb-theme-authoring is a skill published in the GitHub repository get-bb/bb (4,482 stars, last pushed today), licensed MIT. It adds 20 tokens to every session and 1,223 once invoked, about $0.0001 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 2026-09-02.
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