Write your own skills

A skill is a folder with a SKILL.md file that teaches the agent one repeatable job, such as your house format for an earnings note. LangAlpha uses the open Agent Skills format: YAML front matter with a name and a description, followed by Markdown instructions, plus optional files the instructions point to. This page covers how to write a skill the agent picks up at the right moment and how to install it.

Write the description as a trigger

The agent does not read every skill. On each turn it sees one line per enabled skill, the name and the description, and it reads a skill’s SKILL.md only when a task fits that line. The description alone decides whether your skill loads. It costs context on every model call, and it is capped at 1,024 characters.

Say what the skill produces and when to use it, with the phrases you would actually type. The built-in earnings-preview skill does this:

---
name: earnings-preview
description: "Pre-print setup for a company about to report: the expectation bar, EPS-quality watch, call questions, scenarios and the reaction framework. Triggers on earnings preview, what to watch for [company] earnings, pre-earnings setup, preview Q[N]."
---

Keep SKILL.md short and push detail into files

The whole SKILL.md body is loaded into context when the skill runs, and it can be at most 64 KB. Put the steps in it and move long reference material into a references/ folder, then tell the agent when to read each file. The built-in research-conventions skill is a worked example: its SKILL.md lists five reference files, each with the situation that calls for it. earnings-preview ends each step with a “Complete when” line so the agent knows when the step is done.

Name it and give it a slash command

A name is 1 to 64 characters: lowercase letters, digits and single hyphens, with no leading or trailing hyphen. You run a skill by typing / in the chat box. The command defaults to the skill name. Set a command: line in the front matter, or use Edit command on the skill’s page, to change it. A command uses lowercase letters, digits and hyphens, up to 64 characters.

You cannot reuse the name or command of a built-in skill, or the composer’s own commands: subagent, compact, compaction, summarize, offload and truncate. An upload that clashes is refused with the reason.

Upload limits

Limit	Value
Archive (zip)	2 MB
Uncompressed total	8 MB
One file	1 MB
Files per skill	64
`SKILL.md`	64 KB
Description	1,024 characters
Skills per account	200, with 32 MB in total

Open Plugins, then Skills, and upload a folder, a .zip or a SKILL.md, or paste one in. A zip needs SKILL.md at its root or inside one top-level folder. The upload drops hidden files (including a stray .env), node_modules and macOS leftovers, and it rejects symlinks and unsafe paths.

Choose a tier

An uploaded skill is available in every workspace. You can instead keep a skill in one workspace. A copy uploaded to a workspace shadows a user skill of the same name there, so you can run a variant in one place without changing the rest. Moving a skill between the two scopes is refused when the destination already has that name. Built-in and plugin skills can be switched off per workspace but not deleted.

Install from GitHub, or package a plugin

On the Plugins page you can install from a public git URL. A repository with no plugin.json still installs when it holds folders with a SKILL.md: each becomes a skill of a plugin named after the folder or repository. You can also ask the agent to install a skill from a repository into the workspace.

To ship skills together with connectors, make a plugin. It follows the Agent Plugins format: a plugin.json, an mcp.json for MCP servers, a skills/ folder with one directory per skill, and an agents/ folder for subagents. Uninstalling the plugin removes its skills, connectors and subagents together. Skill, plugin or MCP server? explains when to use which.