# Memory and skills (/docs/concepts/memory-and-skills)



The **`memory`** config block materialises instructions and skills into the agent's workspace at startup. The backend reads them as part of its normal context, so the agent has persistent knowledge across sessions.

```json
{
  "memory": {
    "instructions": "./memory/instructions.md",
    "skills": ["./memory/skills/code-review", "./memory/skills/testing"]
  }
}
```

Relative paths resolve against the directory containing the config file.

## Where files are written [#where-files-are-written]

Each backend has its own conventions, and core maps them for you:

| Backend     | Instructions file                 | Skills directory       |
| ----------- | --------------------------------- | ---------------------- |
| Copilot     | `.github/copilot-instructions.md` | `.github/skills/`      |
| Claude      | `CLAUDE.md`                       | `.claude/skills/`      |
| OpenCode    | `.opencode/instructions.md`       | `.opencode/skills/`    |
| Codex       | `.codex/instructions.md`          | `.agents/skills/`      |
| Antigravity | `AGENTS.md`                       | `.antigravity/skills/` |

Codex also reads `AGENTS.md` in the workspace root for project-level instructions.

## Skill format [#skill-format]

A skill is a folder with a `SKILL.md` containing frontmatter and instructions:

```markdown title="memory/skills/code-review/SKILL.md"
---
name: code-review
description: Provides code review guidelines and checklists
license: MIT
compatibility:
  - copilot
  - opencode
allowed-tools:
  - read_file
  - search_files
---

# Code Review Skill

Instructions for the model on how to perform code reviews...
```

The `name` must be kebab-case and at most 64 characters. A skill folder may also contain `scripts/`, `references/` and `assets/`.

## Memory skills versus card skills [#memory-skills-versus-card-skills]

* `memory.skills` are internal instructions for the model. They are never exposed externally.
* `agentCard.skills` are public metadata for discovery.

Keep them in sync by hand. They often deserve different wording: the card entry is short and aimed at orchestrators, while the memory skill is detailed and technical.