> ## Documentation Index
> Fetch the complete documentation index at: https://amplifysecurity-eng-1993-initial-docs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# Skills
> Package a procedure an agent loads on demand — and when to write one instead of an agent.
## 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](/harness/tool-reference). |
| `license` | No | string | Optional license string. |
| `compatibility` | No | object | `min-version` / `max-version` constraints. |
| `metadata` | No | object | Free-form key/value data. |
```markdown theme={null}
---
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](/harness/detections). |
The scanner agents also draw on an internal library of class-specific analysis skills, which is what
distinguishes the `standard` and `comprehensive` [profiles](/harness/agent-library#scanning) 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//SKILL.md # available in every session
./skills//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 ` | 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.
## Next steps
Turn a procedure's results into a permanent rule.
Where skills are authored and toggled.