---
title: skill_update
description: Update an ad-ops playbook (Skill), guarded by base_revision so concurrent edits aren't clobbered.
---

Updates an existing **Skill**. Requires the `skill:write` scope. Always fetch the Skill with [`skill_get`](/mcp/tools/skill-get) first so you have its current `revision`, then pass it back as `base_revision` — the update is rejected if the Skill changed since you read it.

## Input

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `skill_name` | `string` | yes | The current slug identifying which Skill to update. |
| `base_revision` | `number` | yes | The `revision` you last read via `skill_get`. Guards against overwriting a race. |
| `name` | `string` | no | New display name. |
| `description` | `string` | no | New discovery description. |
| `body` | `string` | no | New playbook instructions. |
| `slug` | `string` | no | Optional new slug (a deliberate rename); normalized to kebab-case. |

Only the fields you pass change; the rest carry forward. On success the `revision` is bumped.

## Output

The updated Skill, including its new `revision`.

## Example

> _"Add a rule to the weekly-meta-audit skill: always end with a one-line summary."_

```ts
const skill = skill_get({ skill_name: 'weekly-meta-audit' }); // revision 3
skill_update({
  skill_name: 'weekly-meta-audit',
  base_revision: skill.revision,
  body: `${skill.body}\n\n## Rules\n- End with a one-line summary.`,
});
// → { slug: 'weekly-meta-audit', revision: 4, … }
```

:::warning[Renaming the slug moves the handle]

Passing `slug` renames the agent-facing handle. Anything (an agent, a saved prompt) that referenced the old slug will need updating — it's a deliberate rename, not an alias.

:::

## Errors

- **Stale revision** — the Skill changed since you read it. Re-fetch with `skill_get` and retry with the latest `base_revision`.
- **Slug conflict** — a rename collided with another live Skill's slug.
- **Invalid slug** — the new slug has no letters or digits.
- **Not found** — no Skill with that slug exists.
- `401` or `403` — see [Errors](/mcp/errors), which every tool shares. This one needs `skill:write`.