---
title: Skill
order: 3
description: Pre-authored capability bundles the agent uses to investigate.
---

# Skill

A **skill** is a pre-authored capability bundle the agent can invoke. Skills
encode domain expertise — "how to triage a TiKV slow-write incident", "how to
query Clinic for slow logs" — so you don't have to spell out the procedure
every time.

## What a skill contains

- A short description telling the agent **when** to use it.
- Step-by-step instructions and reference material.
- Optional helper scripts and prompts.
- Required tool / connector dependencies.

## Built-in skills

Investibook ships with diagnostic skills for the common TiDB Cloud investigation
paths, such as:

- **tikv-slow-diagnosis** — TiKV latency triage.
- **tikv-fast-tune** — performance bottleneck decision tree.
- **transaction-oncall-handbook** — transaction-specific incidents.
- **pd-oncall-handbook** — PD scheduling, placement rules, TSO.
- **clinic-api** — query Clinic for metrics, logs, and profiles.
- **tidb-perf-diagnosis** — end-to-end TiDB performance analysis.

Browse the full list in the **Skill Hub** (Settings → Skill Hub) or in any
workspace's sources panel.

## How the agent picks a skill

The agent routes based on:

1. The active sources (cluster type, ticket category).
2. The keywords in your question.
3. The skill's own description and trigger phrases.

You can also **hint** explicitly — see
[How-to → Use Investibook from the CLI](/docs/how-to/use-cli) for examples like:

```text
Use skill tidb-perf-diagnosis and skill clinic-api to help me understand
the hotspot issue in cluster xxxx
```

## Custom skills

You can author your own skill and upload it via the Skill Hub. It applies at
the workspace level only — to share with the rest of your team, submit a PR
to [tidbcloud/nutshell-skills](https://github.com/tidbcloud/nutshell-skills).
See [How-to → Author and share a skill](/docs/how-to/author-skill).