building-tools

building-tools is a skill for Claude Code, Codex from celigo/ai. It costs 57 tokens per session (4,683 once invoked), scanned A, original, MIT.

A guide for building reusable Celigo tools: defined units of integration logic that can look up, transform, import, or branch data.

In plain words
What is it for?
Use it to create tool inputs and outputs, add processing steps, configure routing, and compose tools into larger operations.
Why use it?
It avoids rebuilding the same integration logic separately for flows, APIs, agents, or other callers.

Skill for Claude CodeCodex

Part of the celigo plugin — 24 skills, 5 commands, 1 MCP server shipped together

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.

agentmods
npx agentmods add skills/celigo/ai/building-tools
Any agent
npx skills add celigo/ai --skill building-tools
Clone the repo
git clone --depth 1 https://github.com/celigo/ai

Made for: Claude Code, Codex.

Or install celigo, the plugin that ships this one along with the rest of its 24 skills, 5 commands, 1 MCP server.

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 building-tools

README.md
[![agentmods](https://agentmods.dev/badge/skills/celigo/ai/building-tools.svg)](https://agentmods.dev/skills/celigo/ai/building-tools)
Your own site
<a href="https://agentmods.dev/skills/celigo/ai/building-tools"><img src="https://agentmods.dev/badge/skills/celigo/ai/building-tools.svg" alt="Measured on agentmods" height="20"></a>
Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,683 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00057 $0.04683
Opus 5 $0.00028 $0.02341
Sonnet 5 $0.00011 $0.00937
Haiku 4.5 $0.00006 $0.00468

Measured 4d ago against content hash dcdbf598f39e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

building-tools 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 4d 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.

skills/building-tools/SKILL.md · 309 lines

How it starts

The opening of the file, as written. The whole thing — 309 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Building Tools

A tool is Celigo's first-class reusable building block. It encapsulates logic -- lookups, imports, transforms, branching -- behind a defined input and output contract. Build it once, use it everywhere: from Flows, APIs, AI Agents, MCP Servers, and other Tools.

Tool Concepts

Why tools exist: Without tools, users build the same lookup-transform-import patterns repeatedly across Flows, APIs, and Agents. Tools solve this by providing a governed, composable abstraction: one definition, many consumers, consistent behavior.

When to build a tool:

  • You're building an MCP server -- MCP servers expose tools as endpoints; every piece of logic an MCP server offers must be a tool
  • The same logic is needed by 2+ consumers (flows, APIs, agents, MCP servers) -- build once, call everywhere
  • You want connection flexibility -- callers can pass different connections to the same tool definition
  • You're composing smaller pieces -- tools can call other tools for nested orchestration

When NOT to build a tool:

  • The logic is specific to one flow or API and won't be reused -- inline it as a lookup/import processor directly
  • You need abstract/instance templating for multi-tenant patterns -- use abstract flows

Tool vs API: the split is how the work gets invoked. An API is reachable from outside Celigo over HTTP (a partner system, a customer-facing app). A tool is reachable only from inside Celigo (flow steps, AI agents, APIs, other tools). If a recipe must be reachable from both, build it as a tool and expose the tool behind an API endpoint -- the tool stays available to inside-Celigo consumers at the same time.

Tool vs flow: tools don't start themselves -- no schedule, no listeners, no flow runtime controls (proceedOnFailure and friends are the consumer's concern), and no abstract/instance layer (a tool is already the unit of reuse; per-environment variation is handled by the consumer-bound connection model). "Every night, do X" or "when a webhook arrives, do Y" is a flow -- the tool may be the thing the flow does.

Read the full file on GitHub · 309 lines

Files

What ships with it

5 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. 4d ago First seen · 309 lines · 57 tokens per session scan A dcdbf598f39e

Subscribe to this mod's changes

building-tools is a skill published in the GitHub repository celigo/ai (3 stars, last pushed yesterday), licensed MIT. It adds 57 tokens to every session and 4,683 once invoked, about $0.0003 per session on Opus 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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