agentback-demo: Skill for Claude Code

.agents/skills/agentback/SKILL.md

agentback is a skill for Claude Code, Codex from ninemindai/agentback-demo. It costs 220 tokens per session (3,156 once invoked), scanned A, original, MIT.

A TypeScript framework for building REST web APIs and MCP servers from shared Zod schemas. Zod is a library that describes and checks data shapes; MCP is a standard way for AI clients to call tools.

In plain words
What is it for?
Use it to build Node.js services with dependency injection, REST endpoints, OpenAPI descriptions, or MCP tools over standard input/output or HTTP.
Why use it?
It keeps validation, generated API descriptions, tool inputs, and documentation based on the same definitions.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is ninemindai/agentback-demo's own configuration. It tells Claude Code and Codex how to work on agentback-demo 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 agentback-demo configures →

Reuse

Borrowing it

Nothing to install: this file belongs to ninemindai/agentback-demo. 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/ninemindai/agentback-demo/main/.agents/skills/agentback/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/ninemindai/agentback-demo

Made for: Claude Code, 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 agentback

README.md
[![agentmods](https://agentmods.dev/badge/skills/ninemindai/agentback-demo/agentback/github.svg)](https://agentmods.dev/skills/ninemindai/agentback-demo/agentback)
Your own site
<a href="https://agentmods.dev/skills/ninemindai/agentback-demo/agentback"><img src="https://agentmods.dev/badge/skills/ninemindai/agentback-demo/agentback/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 agentback

Your own site · 80×15
<a href="https://agentmods.dev/skills/ninemindai/agentback-demo/agentback"><img src="https://agentmods.dev/badge/skills/ninemindai/agentback-demo/agentback.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 220 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,156 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00220 $0.03156
Opus 5.5 $0.00088 $0.01262
Sonnet 5.5 $0.00044 $0.00631
Haiku 4.5 $0.00022 $0.00316

Measured 2mo ago against content hash 847a165aa4f6, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

agentback 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 2mo 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.

.agents/skills/agentback/SKILL.md · 217 lines

How it starts

The opening of the file, as written. The whole thing — 217 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Build REST + MCP Services with AgentBack

AgentBack is an ESM/Zod/MCP fork of LoopBack 4 — a TypeScript DI framework (@agentback/core + @agentback/context) with HTTP and MCP servers that discover your code by tag in one Context. Its bet: a single Zod schema is the validator, the z.infer type, the OpenAPI contract, the MCP input/output, and the rendered docs — simultaneously. Change the schema and every contract changes in one edit; disagreements surface as a TypeScript error at the decorator, a startup throw, or a failing test.

ESM-only, Node 22.13+, TypeScript 6, pnpm workspaces. Relative imports use .js extensions. This is a slim modern subset — no LB4 sequences/actions, no @loopback/repository, no per-parameter @param/@requestBody.

Architecture Decision Tree

  1. DI container, bindings, components, lifecycle? → Dependency injection & components (dependency-injection.md). (Same model as @loopback/core; this layer is a faithful port.)
  2. HTTP/REST API with validation + OpenAPI? → Zod-first REST (rest-and-openapi.md)
  3. Tools / resources / prompts for MCP clients (Claude, Cursor, agents), over stdio or HTTP? → MCP tools (mcp-tools.md)
  4. Share schemas/types between server and a typed client (no codegen)? → Schema sharing & client (schema-sharing-and-client.md)
  5. Authentication, authorization, scopes, rate limiting (REST or MCP/HTTP)? → Auth & rate limiting (auth-and-rate-limiting.md)
  6. Health/metrics, middleware, subclassing the dispatcher, packaging? → Composition & operations (composition-and-operations.md)

Getting Started: scaffold a new app

Don't hand-write package.json/tsconfig.json. Scaffold with the create-agentback CLI — npm create agentback resolves to it:

Read the full file on GitHub · 217 lines

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. 2mo ago First seen · 217 lines · 220 tokens per session scan A 847a165aa4f6

Subscribe to this mod's changes

agentback is a skill published in the GitHub repository ninemindai/agentback-demo (0 stars, last pushed 1mo ago), licensed MIT. It adds 220 tokens to every session and 3,156 once invoked, about $0.0009 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 2026-08-31.

Related

agentback compared with skills from other repositories

agentback next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
agentbackninemindai/agentback-demoSkill01mo agoMITA220Claude Code, Codex
okx-cex-botokx/agent-trade-kitSkill5014d agoMITA133Claude Code, Codex
fluent-developmentserac-labs/seracSkill7717d agoApache-2.0A77Claude Code
build-appunblockingapi/mcpSkill2yesterdayMITA76Claude Code
templatesunblockingapi/mcpSkill2yesterdayMITA80Claude Code
fleet-supervisorApra-Labs/apra-fleetSkill106yesterdaynoneA70Claude Code, Codex
add-fetcherkoalyptus/ls-apisSkill1yesterdayMITA20Claude Code, Codex