A Skill is a reusable, workspace-scoped bundle of instructions (and optionally helper files) that an agent can attach to extend its capabilities. The simplest skill is a single SKILL.md markdown body; more complex skills are multi-file bundles uploaded as a zip.
Skills compose with Crew Agents — when an agent runs in a sandbox, every attached skill is materialized into the sandbox filesystem at start-up.
Skill shape
A skill row (skill table) carries:
| Column | Notes |
|---|---|
name | Unique within the workspace. |
description | One-line summary shown in the picker. |
content | The SKILL.md body. Source of truth for legacy single-file skills; mirrored as a skill_file row for multi-file skills. |
bundleVersion | Content hash. Sandboxes cache extracted bundles by (skillId, bundleVersion) so identical bundles never re-download. |
Multi-file skills additionally have rows in skill_file:
| Column | Notes |
|---|---|
path | Relative POSIX path inside the bundle, e.g. SKILL.md, scripts/extract.py. No leading /, no ... |
mimeType, size | Standard metadata. |
storageKey | Object key in the skills storage context. |
sha256 | Verified on extract. |
Authoring a skill
- Open Crew › Skills and click New Skill.
- Name it, write a one-line description, write the
SKILL.mdbody. - Optionally upload a zip with additional files (scripts, prompt fragments, fixtures). The zip's tree becomes the bundle layout and
bundleVersionis recomputed from the contents.
The detail page lets you edit the markdown inline. Saving updates bundleVersion, which forces sandboxes to re-extract the bundle on the next run.
Attaching to an agent
On a Crew Agent detail page, the Skills panel attaches/detaches skills via the agent_skill join table. At dispatch time the Agents block sends the list of attached skill IDs + bundle versions to the sandbox; the sandbox downloads any bundle it does not already have cached.
Skills are different from Tools. Skills extend prompting and bring helper files into the run; Tools (Custom Tools or MCP Servers) are callable functions exposed to the model. See Crew › Tools.
Source
apps/actana/app/workspace/[workspaceId]/w/crew/skills/— UIapps/actana/app/api/workspaces/[workspaceId]/skills/— APIpackages/db/schema.ts—skill,skill_file,agent_skill