phase-4-api

phase-4-api is a skill for Claude Code from de-monkey-v/marketplace. It costs 120 tokens per session (1,990 once invoked), scanned A, original, no licence file.

A guide for designing and building backend APIs, which let software communicate with other software. It also describes a way to check APIs without writing separate test scripts.

In plain words
What is it for?
Use it when planning or implementing REST APIs, backend services, or individual endpoints, including API design discussions in several languages.
Why use it?
It helps turn API requirements into working endpoints and check whether they behave correctly without maintaining a collection of test scripts.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: agent in frontmatter.

Part of the bkit plugin — 27 skills, 2 commands, 16 agents shipped together

Good fit Use it when planning or implementing REST APIs, backend services, or individual endpoints, including API design discussions in several languages.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/de-monkey-v/marketplace/phase-4-api
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.

Any agent
npx skills add de-monkey-v/marketplace --skill phase-4-api
Clone the repo
git clone --depth 1 https://github.com/de-monkey-v/marketplace

Made for: Claude Code.

Or install bkit, the plugin that ships this one along with the rest of its 27 skills, 2 commands, 16 agents.

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 phase-4-api

README.md
[![agentmods](https://agentmods.dev/badge/skills/de-monkey-v/marketplace/phase-4-api/github.svg)](https://agentmods.dev/skills/de-monkey-v/marketplace/phase-4-api)
Your own site
<a href="https://agentmods.dev/skills/de-monkey-v/marketplace/phase-4-api"><img src="https://agentmods.dev/badge/skills/de-monkey-v/marketplace/phase-4-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 phase-4-api

Your own site · 80×15
<a href="https://agentmods.dev/skills/de-monkey-v/marketplace/phase-4-api"><img src="https://agentmods.dev/badge/skills/de-monkey-v/marketplace/phase-4-api.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 120 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,990 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 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 $0.00120 $0.01990
Opus 5.5 $0.00048 $0.00796
Sonnet 5.5 $0.00024 $0.00398
Haiku 4.5 $0.00012 $0.00199

Measured 2mo ago against content hash 877cc1959376, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

phase-4-api 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.

plugins/bkit/skills/phase-4-api/SKILL.md · 291 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

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 · 291 lines · 120 tokens per session scan A 877cc1959376

Subscribe to this mod's changes

phase-4-api is a skill published in the GitHub repository de-monkey-v/marketplace (2 stars, last pushed 7mo ago), with no licence file. It adds 120 tokens to every session and 1,990 once invoked, about $0.0005 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.

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