Hermes-Walkie-Talkie: Skill for Codex

.agents/skills/build-bun-fastify-api/SKILL.md

build-bun-fastify-api is a skill for Codex from TheSethRose/Hermes-Walkie-Talkie. It costs 80 tokens per session (578 once invoked), scanned A, original, no licence file.

A set of instructions for building and maintaining TypeScript APIs that use Bun, a JavaScript runtime, and Fastify, a web-server framework.

In plain words
What is it for?
Use it for Fastify routes, Bun services, file uploads, bearer authentication, Zod and environment-variable validation, child processes, local storage, API contracts, and related TypeScript backend work.
Why use it?
It gives an agent guidance for common backend tasks and helps keep work aligned with the stated API technologies and concerns.

Skill for Codex

Written for Codex: agents/openai.yaml present. Also seen: installed under .agents/ (shared by several agents).

This is TheSethRose/Hermes-Walkie-Talkie's own configuration. It tells Codex how to work on Hermes-Walkie-Talkie itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything Hermes-Walkie-Talkie configures →

Reuse

Borrowing it

Nothing to install: this file belongs to TheSethRose/Hermes-Walkie-Talkie. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/TheSethRose/Hermes-Walkie-Talkie/main/.agents/skills/build-bun-fastify-api/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/TheSethRose/Hermes-Walkie-Talkie

Made for: Codex.

Wrote 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.

agentmods badge for build-bun-fastify-api

README.md
[![agentmods](https://agentmods.dev/badge/skills/thesethrose/hermes-walkie-talkie/build-bun-fastify-api/github.svg)](https://agentmods.dev/skills/thesethrose/hermes-walkie-talkie/build-bun-fastify-api)
Your own site
<a href="https://agentmods.dev/skills/thesethrose/hermes-walkie-talkie/build-bun-fastify-api"><img src="https://agentmods.dev/badge/skills/thesethrose/hermes-walkie-talkie/build-bun-fastify-api/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.

agentmods 80×15 button for build-bun-fastify-api

Your own site · 80×15
<a href="https://agentmods.dev/skills/thesethrose/hermes-walkie-talkie/build-bun-fastify-api"><img src="https://agentmods.dev/badge/skills/thesethrose/hermes-walkie-talkie/build-bun-fastify-api.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 80 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 578 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 5.1 $0.00080 $0.00578
Opus 5 $0.00040 $0.00289
Sonnet 5 $0.00016 $0.00116
Haiku 4.5 $0.00008 $0.00058

Measured 11d ago against content hash dbaa75ff87b2, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

build-bun-fastify-api 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 11d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/inspect_bun_fastify_project.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

- focused curl/inject checks when behavior changed
.agents/skills/build-bun-fastify-api/SKILL.md · 41 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

Files

What ships with it

6 files 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.

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. 11d ago First seen · 41 lines · 80 tokens per session scan A dbaa75ff87b2

Subscribe to this mod's changes

build-bun-fastify-api is a skill published in the GitHub repository TheSethRose/Hermes-Walkie-Talkie (2 stars, last pushed 2mo ago), with no licence file. It adds 80 tokens to every session and 578 once invoked, about $0.0004 per session on Opus 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 2026-08-31.

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