Pre-built skills vs custom skills — when to use each

There are two ways to give your AI coding agent new capabilities with AIsa Agent Skills: install a pre-built skill from the OpenClaw-Skills registry, or write your own SKILL.md from scratch. The right choice depends on whether your use case is already covered.

The core difference

Use a pre-built skill when…

The capability already exists in the registry. If you need web search, financial data, Twitter/X access, image/video generation, or YouTube research — there's already a skill for it. Installing it takes one command and it comes with tested scripts and worked examples.

You want the AIsa team to maintain it. Pre-built skills are updated when the underlying APIs change. You don't have to track API deprecations or rewrite instructions when endpoints move.

You're prototyping quickly. aisa skills install market and a new Claude Code session is all you need to start querying live stock prices. Writing, testing, and maintaining an equivalent custom skill takes meaningfully longer.

Example: install and use the market skill

# Install
aisa skills install market

# Open a new agent session and ask:
# "Pull the last 30 days of NVDA price data and flag any days where
#  the move exceeded 5%. Cross-reference with earnings dates."

The agent reads the market skill description, loads the SKILL.md instructions, runs the bundled Python client, and calls AIsa's finance API — without you writing any code.

Write a custom skill when…

You need to call your own internal APIs. Pre-built skills cover AIsa's public API catalogue. They can't query your company's internal data warehouse, CRM, or proprietary service. For those, write a SKILL.md that describes your internal endpoints and authentication.

The existing skill doesn't cover your exact use case. If you need a very specific workflow — a multi-step process combining several APIs in a particular order — a custom skill lets you encode exactly that sequence in the instructions body.

You want to share domain-specific knowledge with the agent. SKILL.md files aren't just API wrappers. You can include domain context, decision rules, output formatting requirements, and caveats that your team has learned from production use.

You want to publish a skill for others. Custom skills can be submitted to the OpenClaw-Skills registry as a pull request. If you've built something useful on top of AIsa APIs, contributing it benefits the whole ecosystem.

Example: scaffold and edit a custom skill

# Start from the closest built-in template
aisa skills init internal-crm --template default

# Edit the generated SKILL.md
# - Set name, description, and metadata
# - Write instructions that explain your CRM's auth and endpoints
# - Add example curl/Python commands for common queries

The description field is the most important line you'll write. It's what your agent reads at startup to decide when to activate the skill. Be specific about the trigger condition:

# ❌ Too generic — the agent won't know when to use this
description: "Internal CRM access."

# ✅ Clear trigger — the agent knows exactly when this applies
description: "Look up customer account details, support history, and
  renewal dates from the internal Salesforce CRM. Use when the user
  asks about a specific customer or account."

Quick decision guide

Is there a pre-built skill in the OpenClaw registry for this?
│
├── YES → Does it cover your use case without modification?
│         ├── YES → aisa skills install <slug>
│         └── NO  → aisa skills init <name> (customise or extend)
│
└── NO  → Does it involve an AIsa public API not yet in the registry?
          ├── YES → aisa skills init <name> --template <closest>
          │         (and consider submitting a PR to OpenClaw-Skills)
          └── NO  → aisa skills init <name> --template default
                    (write instructions for your internal API)

What's next

• Available Skills — full catalogue of pre-built skills with GitHub links
• Quickstart — install your first skill in 5 minutes
• Overview — how SKILL.md files work and how agents load them
• Getting Started with AIsa — if you're new to the AIsa API