> ## Documentation Index > Fetch the complete documentation index at: https://qodex.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # Skills > Skills let Qodex specialize its agent for a specific testing job, such as API testing, UI scenario authoring, security review, or your own internal workflow. # Skills Skills are reusable instructions that teach Qodex how to handle a specific kind of work. When you ask Qodex to test an API, crawl a UI, check security issues, or write scenarios, the coordinator chooses the skill that best matches the job. The skill gives the agent a focused workflow, a tool set, and rules for what good output looks like. ## Why skills matter Without skills, every agent run would start from a generic prompt. Skills make Qodex behave like a specialist: * API testing skills know how to inspect endpoints, create scenarios, and separate broken tests from real API bugs. * UI testing skills know how to drive the browser, collect artifacts, and save repeatable scenarios. * Security skills know OWASP checks, inverted pass/fail semantics, and evidence rules. * Custom skills let your team encode internal standards without changing Qodex code. That means the product can adapt to your stack while still keeping testing behavior predictable. ## What a skill is A skill is one `.skill.md` file. The YAML frontmatter defines the skill id, name, description, allowed tools, iteration limits, and optional sub-agent behavior. The markdown body is the instruction prompt Qodex uses when that skill is active. ```text theme={null} --- id: api name: API Testing description: Tests API endpoints and creates verified, passing test scenarios. tools: categories: [api, memory, scenario, reporting] --- # API Testing Follow this workflow... ``` You can use the built-in skills as shipped, override one for a project, or add a new skill for your own workflow. ## How Qodex uses skills The coordinator has two ways to use a skill: | Method | What happens | Best for | | ---------------- | ------------------------------------------------------------------ | --------------------------------------------------------- | | `invoke_skill` | Adds the skill instructions to the current agent turn. | Focused tasks the coordinator can do directly. | | `spawn_subagent` | Starts an isolated sub-agent with the skill and returns a summary. | Parallel work, large scans, or specialized investigation. | For example, the UI skill can split a broad request into smaller flows and spawn `ui-author` sub-agents to write each scenario. The API skill can do the same with `api-author`. ## What you can customize You can customize: * The workflow the agent follows. * The tools the agent may call. * The severity rubric used for findings. * Whether the skill can spawn sub-agents. * How many tool-call iterations the skill may spend. * The exact rules the agent must obey before reporting success. This is useful when your organization has a custom compliance checklist, a proprietary auth flow, a GraphQL or gRPC testing pattern, or a domain-specific definition of severity. ## Built-in and project skills Built-in skills ship with Qodex. Project skills can be added on top. If a project skill uses the same `id` as a built-in skill, the project version replaces the built-in for that project. There is no merge. Copy the built-in skill first, then edit the parts that should change. ## Next steps Learn the fields that define a skill. See the skills Qodex ships with today. Create a skill for your own workflow. Share skills across projects or teams.