build-tools

build-tools is a skill for Claude Code from umbraco/Umbraco-MCP-Base. It costs 43 tokens per session (2,424 once invoked), scanned C, original, MIT.

A build step that turns selected Umbraco API groups into MCP tool collections. MCP is a standard way for AI assistants to use external tools.

In plain words
What is it for?
Use it after API discovery to build all collections or one named collection, such as forms. It creates tool files, collection indexes, and registrations, but not tests.
Why use it?
It removes the manual work of creating tool files and registering each API collection. It uses the discovery results and generated API client already in the project.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the umbraco-mcp-skills plugin — 13 skills, 7 agents shipped together

Good fit Use it after API discovery to build all collections or one named collection, such as forms. It creates tool files, collection indexes, and registrations, but not tests.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add umbraco/Umbraco-MCP-Base
Claude Code
/plugin install umbraco-mcp-skills

Made for: Claude Code.

Or install umbraco-mcp-skills, the plugin that ships this one along with the rest of its 13 skills, 7 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 build-tools

README.md
[![agentmods](https://agentmods.dev/badge/skills/umbraco/umbraco-mcp-base/build-tools/github.svg)](https://agentmods.dev/skills/umbraco/umbraco-mcp-base/build-tools)
Your own site
<a href="https://agentmods.dev/skills/umbraco/umbraco-mcp-base/build-tools"><img src="https://agentmods.dev/badge/skills/umbraco/umbraco-mcp-base/build-tools/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-tools

Your own site · 80×15
<a href="https://agentmods.dev/skills/umbraco/umbraco-mcp-base/build-tools"><img src="https://agentmods.dev/badge/skills/umbraco/umbraco-mcp-base/build-tools.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,424 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 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 $0.00043 $0.02424
Opus 5.5 $0.00017 $0.00970
Sonnet 5.5 $0.00009 $0.00485
Haiku 4.5 $0.00004 $0.00242

Measured today against content hash 2514732ba214, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade C, and why

build-tools scanned grade C with 2 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 today.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/__tests__/list-operations.test.ts, scripts/list-operations.ts), 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.

Downloads and executes remote codehighSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

curl -fsSk "{swaggerUrl}" | node ${CLAUDE_PLUGIN_ROOT}/skills/build-tools/scripts/list-operations.ts {collection}

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -fsSk "{swaggerUrl}" | node ${CLAUDE_PLUGIN_ROOT}/skills/build-tools/scripts/list-operations.ts {collection}
plugins/umbraco-mcp-skills/skills/build-tools/SKILL.md · 259 lines

How it starts

The opening of the file, as written. The whole thing — 259 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Build Tools

Generate MCP tool collections from the API groups selected during discovery. This skill reads .discover.json and the swagger spec, then builds tool files one collection at a time.

IMPORTANT: This skill ONLY creates tool files, collection indexes, and registrations. Do NOT create any test files, test setup, test builders, test helpers, or __tests__/ directories. Testing is handled separately by the /build-tools-tests skill.

Prerequisites

Before running, ensure:

  1. You have run npx @umbraco-cms/create-umbraco-mcp-server discover (.discover.json exists)
  2. The API client has been generated (src/umbraco-api/api/generated/ directory exists — if not, run npm run generate)

Arguments

  • No arguments: build all collections from .discover.json
  • Single collection name: build only that collection (e.g. /build-tools form)

Agents

This skill orchestrates the following agents — use them for the relevant steps:

Agent When to use
mcp-tool-creator Creating each tool file (Step 3b)
mcp-tool-description-writer Writing tool descriptions (Step 3b)
mcp-tool-reviewer Reviewing tools for LLM-readiness (Step 4)

Workflow

Process one collection at a time. Complete each collection fully before starting the next.

Step 0: Read Discovery Manifest

Read .discover.json from the project root:

{
  "apiName": "Umbraco Forms Management API",
  "swaggerUrl": "https://localhost:44324/umbraco/swagger/forms-management/swagger.json",
  "baseUrl": "https://localhost:44324",
  "collections": ["form", "form-template", "field-type", "folder"]
}

If an argument was provided, filter to only that collection. If .discover.json doesn't exist, tell the user to run npx @umbraco-cms/create-umbraco-mcp-server discover first.

Step 1: Check Generated Client

Check if src/umbraco-api/api/generated/ exists and contains .ts files. If not, run:

npm run generate

Then read the generated files to understand:

  • The API client function name (e.g. getFormsManagementAPI)
  • The available Zod schemas (in *.zod.ts files)
  • The available client methods and their signatures

Read the full file on GitHub · 259 lines

Files

What ships with it

2 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. today Changed · +11 lines scan A → C 2514732ba214
  2. 2mo ago First seen · 248 lines · 43 tokens per session scan A d76e13bcb479

Subscribe to this mod's changes

build-tools is a skill published in the GitHub repository umbraco/Umbraco-MCP-Base (2 stars, last pushed yesterday), licensed MIT. It adds 43 tokens to every session and 2,424 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Related

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build-tools next to 6 skills from other repositories
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