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/sjarmak/coding-agent-workflowsnpx agentmods add skills/sjarmak/coding-agent-workflows/bun-runtimeWrote 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/sjarmak/coding-agent-workflows/bun-runtime)<a href="https://agentmods.dev/skills/sjarmak/coding-agent-workflows/bun-runtime"><img src="https://agentmods.dev/badge/skills/sjarmak/coding-agent-workflows/bun-runtime/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/sjarmak/coding-agent-workflows/bun-runtime"><img src="https://agentmods.dev/badge/skills/sjarmak/coding-agent-workflows/bun-runtime.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00034 | $0.00720 |
| Opus 5.5 | $0.00014 | $0.00288 |
| Sonnet 5.5 | $0.00007 | $0.00144 |
| Haiku 4.5 | $0.00003 | $0.00072 |
Grade A, and why
bun-runtime scanned grade A with 1 finding 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 28d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
fetch(req) { How it starts
The opening of the file, as written. The whole thing — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Bun Runtime
Use the project's installed version and conventions. Verify version-sensitive APIs,
security settings, and deployment support with documentation-lookup before
applying examples; these patterns are reference guidance, not a tested guarantee
for every current release. Do not replace an existing toolchain solely to match
an example.
Bun is a fast all-in-one JavaScript runtime and toolkit: runtime, package manager, bundler, and test runner.
When to Use
- Prefer Bun for: new JS/TS projects, scripts where install/run speed matters, Vercel deployments with Bun runtime, and when you want a single toolchain (run + install + test + build).
- Prefer Node for: maximum ecosystem compatibility, legacy tooling that assumes Node, or when a dependency has known Bun issues.
Use when: adopting Bun, migrating from Node, writing or debugging Bun scripts/tests, or configuring Bun on Vercel or other platforms.
How It Works
- Runtime: Drop-in Node-compatible runtime (built on JavaScriptCore, implemented in Zig).
- Package manager:
bun installis significantly faster than npm/yarn. Lockfile isbun.lock(text) by default in current Bun; older versions usedbun.lockb(binary). - Bundler: Built-in bundler and transpiler for apps and libraries.
- Test runner: Built-in
bun testwith Jest-like API.
Migration from Node: Replace node script.js with bun run script.js or bun script.js. Run bun install in place of npm install; most packages work. Use bun run for npm scripts; bun x for npx-style one-off runs. Node built-ins are supported; prefer Bun APIs where they exist for better performance.
Vercel: Set runtime to Bun in project settings. Build: bun run build or bun build ./src/index.ts --outdir=dist. Install: bun install --frozen-lockfile for reproducible deploys.
Examples
Run and install
# Install dependencies (creates/updates bun.lock or bun.lockb)
bun install
# Run a script or file
bun run dev
bun run src/index.ts
bun src/index.ts
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.
- 28d ago First seen · 90 lines · 34 tokens per session scan A e2855e012b11
bun-runtime is a skill published in the GitHub repository sjarmak/coding-agent-workflows (7 stars, last pushed 4d ago), licensed MIT. It adds 34 tokens to every session and 720 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-02.
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