slidevjs/slidev · error · Error

Nothing to update: provide at least one of `content`, `note`

Error message

Nothing to update: provide at least one of `content`, `note`, or `frontmatter`.

What it means

Thrown by the slidev-update-slide MCP tool handler when all of content, note, and frontmatter are null/undefined. The tool is a partial-update primitive; a call that changes nothing is a programming error rather than a no-op, so it is rejected before any data is fetched or written.

Source

Thrown at packages/slidev/node/mcp/server.ts:160

      })
    },
  )

  server.registerTool(
    'slidev-update-slide',
    {
      title: 'Update slide',
      description: 'Update the content, speaker note, and/or frontmatter of a slide. Only the provided fields are changed. Pass an empty string to clear the content or note. In `frontmatter`, only the given keys are patched; pass `null` as a value to delete that key.',
      inputSchema: z.object({
        no: noSchema,
        content: z.string().optional().describe('New Markdown content of the slide (without frontmatter and note)'),
        note: z.string().optional().describe('New speaker note (Markdown, stored as a trailing HTML comment)'),
        frontmatter: frontmatterSchema,
      }),
    },
    async ({ no, content, note, frontmatter }) => {
      if (content == null && note == null && frontmatter == null)
        throw new Error('Nothing to update: provide at least one of `content`, `note`, or `frontmatter`.')
      const data = await ctx.getData()
      const { slide } = await applySlidePatch(data, no, { content, note, frontmatter })
      return result(`Updated slide ${no} in ${slide.source.filepath}.`)
    },
  )

  server.registerTool(
    'slidev-insert-slide',
    {
      title: 'Insert slide',
      description: 'Insert a new slide after an existing slide (into the same markdown file). To add a slide at the very end, pass the last slide number.',
      inputSchema: z.object({
        after: z.number().int().min(1).describe('Slide number (1-based) after which the new slide is inserted'),
        content: z.string().describe('Markdown content of the new slide'),
        frontmatter: frontmatterSchema,
        note: z.string().optional().describe('Speaker note of the new slide'),
      }),
    },

View on GitHub (pinned to 0d798ace58)

Solutions

Include at least one of content, note, or frontmatter in the call.
If the intent was to read the slide, use slidev-get-slide instead.
Pass an empty string ('') to clear content/note - that is a real change and is accepted.

Example fix

// before: nothing to change
await tools['slidev-update-slide']({ no: 3 }) // throws

// after: provide at least one field
await tools['slidev-update-slide']({ no: 3, content: '# Hello' })
// or clear the note:
await tools['slidev-update-slide']({ no: 3, note: '' })

Defensive patterns

Strategy: validation

Validate before calling

function hasUpdateField(p: { content?: unknown; note?: unknown; frontmatter?: unknown }): boolean {
  return p.content != null || p.note != null || p.frontmatter != null
}

// before calling slidev-update-slide:
if (!hasUpdateField({ content, note, frontmatter })) {
  throw new Error('update-slide needs content, note, or frontmatter.')
}

Type guard

function isNonEmptyPatch(p: unknown): p is { content?: string; note?: string; frontmatter?: Record<string, unknown> } {
  if (!p || typeof p !== 'object') return false
  const { content, note, frontmatter } = p as any
  return content != null || note != null || frontmatter != null
}

Try / catch

try {
  await tools['slidev-update-slide']({ no, content, note, frontmatter })
} catch (e) {
  if (e instanceof Error && e.message.startsWith('Nothing to update')) {
    // route to a read instead
    return await tools['slidev-get-slide']({ no })
  }
  throw e
}

Prevention

Construct the update payload conditionally and abort if no field is set.
Use slidev-get-slide for reads; reserve update-slide for real changes.
Pass '' (empty string) to clear content/note - it counts as a change.
Validate the patch client-side before the MCP round-trip.

When it happens

Trigger: Calling slidev-update-slide with an input object missing all three optional fields, or explicitly setting each to null/undefined.

Common situations: An agent calls update-slide as a no-op probe; a client forwards an empty patch object; conditional logic that omits every field when no condition matched.

Related errors

AI-assisted analysis of slidevjs/slidev@0d798ace58 (2026-08-12). Data as JSON: /api/errors/7721f0cd898636bd. Report an issue: GitHub.