Skills

What a skill is

A skill is a documented procedure an agent loads when it becomes relevant. It’s a Markdown file with YAML frontmatter, same as an agent, but it isn’t a participant: it has no model, no budget, and it never runs on its own. An agent calls activate_skill and the skill’s instructions enter its context. The reason skills exist is context economy. A comprehensive scanner might know how to analyze twenty vulnerability classes, but loading all twenty procedures up front would crowd out the code it’s supposed to be reading. Instead it loads the SQL-injection procedure when it’s looking at a query, and the SSRF procedure when it’s looking at an outbound request.

Skill or agent?

Write a skill when	Write an agent when
You’re capturing how to do one thing well	You’re defining a job with its own output
An existing agent could follow your instructions	You need different tool permissions or a different model
The procedure is only relevant sometimes	The work deserves its own budget and can be delegated to
You want it available to many agents	You want to name it as a workflow step

When in doubt, start with a skill. It’s cheaper — nothing to budget, nothing to orchestrate — and you can promote it to an agent later if it grows its own output.

Frontmatter reference

Key	Required	Type	What it does
`name`	Yes	string	How the skill is activated and listed.
`description`	Yes	string, ≤500 chars	When to use this skill. Agents read it to decide whether to activate.
`allowed-tools`	No	string[]	Tools the procedure expects. See the tool reference.
`license`	No	string	Optional license string.
`compatibility`	No	object	`min-version` / `max-version` constraints.
`metadata`	No	object	Free-form key/value data.

---
name: ssrf-analysis
description: Confirms or rules out server-side request forgery where user input reaches an outbound HTTP call. Use when a request URL, host, or path is influenced by request data.
allowed-tools:
  - shell
  - code_lineage
  - ripgrep_search
---

# SSRF analysis

## Confirming

1. Identify the outbound call and the client library in use.
2. Trace the URL argument back to its source with `call_graph`.
3. Establish whether an attacker controls the scheme, host, or path — not merely the query string.
4. Check for an allow-list, a resolved-IP check, or a proxy that constrains the destination.

## Ruling out

Discard the candidate when the host is a compile-time constant, or when the only
attacker-controlled portion is a path segment appended to a fixed host with no
traversal possible.

Like an agent’s, the description is load-bearing: it’s what an agent reads when deciding whether this skill applies.

Built-in skills

Skill	What it does
`vulnerability-scan`	Uses natural-language policy descriptions to find vulnerabilities in application logic.
`opengrep-rule-creator`	Authors OpenGrep rules for detecting a vulnerability or code pattern.
`codeql-rule-creator`	Authors CodeQL queries for vulnerabilities, bug patterns, and code-quality issues.
`policy-detection-creator`	Turns a security requirement into a stored natural-language policy detection.

The scanner agents also draw on an internal library of class-specific analysis skills, which is what distinguishes the standard and comprehensive profiles from basic.

Where to author a skill

Skills are authored in the CLI (as files) or through the API. Unlike agents and detections, there is no skill editor in the web console today.

In the CLI, a skill is a file on disk:

~/.amplify/skills/<name>/SKILL.md    # available in every session
./skills/<name>/SKILL.md             # project-local

Override those locations with AMPLIFY_SKILLS_DIR. Skills load at startup, so restart the CLI after adding one. A skill directory can hold supporting files — reference documents, example rules, helper scripts — next to SKILL.md, and the instructions can point the agent at them.

Using skills in the CLI

Command	What it does
`/skills`	Lists available skills and marks which are active.
`/skill <name>`	Toggles a skill on or off for the session.

Toggling a skill on makes it available immediately, which is the fastest way to test one you’re writing: edit the file, restart, activate, and give the agent a task that should trigger it. Agents also activate skills on their own via activate_skill — manual toggling is for pinning a procedure you specifically want followed.

Get Started

The Harness

Context

Working interactively

Workflows

What a skill is

Skill or agent?

Frontmatter reference

Built-in skills

Where to author a skill

Using skills in the CLI

Next steps

Detections

The CLI

​What a skill is

​Skill or agent?

​Frontmatter reference

​Built-in skills

​Where to author a skill

​Using skills in the CLI

​Next steps

Detections

The CLI

What a skill is

Skill or agent?

Frontmatter reference

Built-in skills

Where to author a skill

Using skills in the CLI

Next steps