vellum-ai/document-editor

Write and edit long-form documents using the built-in rich text editor. Documents open in workspace mode with chat docked to the side. When a request is about writing prose (an article, blog post, report, essay, story, or similar), create it here rather than writing it into the chat response.

Tools

• document_create - Opens a new document editor with an optional title and initial Markdown content. Returns a surface_id for subsequent updates. This is the entry point for any new piece of writing.
• document_update - Updates content in an open document editor by surface_id. Supports replace (overwrite) and append (add to end) modes.
• document_read - Reads the current content of a document by surface_id when it belongs to the current conversation, or when the current actor is the guardian/local user. Use to verify content before editing.
• document_find - Searches a document for text or regex patterns. Returns matching lines with line numbers, match positions, and matched text.
• document_replace_text - Targeted find-and-replace within a document. Supports literal and regex patterns (with backreferences). Optionally limit the number of replacements.
• document_list - Lists documents. Without query, lists the current conversation's documents. With query, searches by title; guardian/local users can search across conversations, while other actors are scoped to the current conversation.
• document_open - Opens an existing document in the editor panel by surface_id. Use this when a document exists but isn't visible in the editor — for example after the user switches devices, refreshes the page, or when the editor panel was closed. Fetches the document from storage and sends it to the client.
• document_delete - Deletes a document by surface_id. Use to clean up unwanted documents.

Creating a new document

This is the default path when the user asks you to write something.

1. Create the document: Call document_create with a title (inferred from the request). Call the tool immediately, not after conversational preamble.
2. Write content in Markdown: Use proper structure (# for titles, ## for sections), bold, _italic_, code blocks, tables, lists, blockquotes as appropriate.
3. CRITICAL - Stream content in chunks: Call document_update MULTIPLE times, not just once. Break content into logical chunks (paragraphs, sections, or every 200-300 words). Call document_update with mode: "append" for EACH chunk separately. When you are streaming into the document you just created, surface_id is optional — omit it and pass only content, and the update targets that document. The user experiences real-time content appearing as you write.

Recovering from a failed update

If a document_update call fails with an Invalid input error, do NOT call document_create again — that produces a duplicate for the user. The most common cause is a missing content field: resend the call with the chunk's Markdown in content. You can omit surface_id to target the document you are currently writing; pass it explicitly only when editing a different existing document.

Editing an existing document

When the user requests changes to a document:

1. Find the surface_id from the <active_documents> context block.
2. Use document_update with the existing surface_id — do NOT call document_create again.
3. Choose the right editing tool:

• document_update with mode: "append" — adding new content to the end.
• document_update with mode: "replace" — ONLY for full rewrites where the majority of the document is changing.
• document_find + document_replace_text — for everything else. Fixing typos, renaming terms, swapping sections, reordering content, adjusting formatting, or any edit that touches only part of the document. This is the default choice for edits. It avoids rewriting the entire document and eliminates the risk of accidentally dropping content.

1. Do NOT use document_update with mode: "replace" for targeted edits. Rewriting the entire document to change a few words or rearrange sections is wasteful and error-prone.

Retrieving existing documents

When the user asks to see, open, or pull up a document:

1. Check the <active_documents> block in your context — it lists all documents in this conversation with their surface_id and title.
2. If the document is NOT in <active_documents>, call document_list with a query matching the document title. For guardian/local users, this searches across previous conversations and sessions.
3. Once you have the surface_id, call document_open to open the editor panel. This surfaces the editor on the client and returns document metadata (surface_id, title, word_count) — not the full content. If you need the actual document text, follow up with document_read.

Never search the filesystem, conversation history, or archives to find a document. Always use document_list with a query.

If the user says they can't see a document you know exists (e.g. after switching from macOS to web, or after a page refresh), call document_open with the surface_id to re-surface the editor panel on their current client.

Find & Replace

Use document_find and document_replace_text for surgical edits that target specific text patterns without rewriting the entire document.

document_find

Search a document for literal text or regex patterns. Parameters:

• surface_id (required) — the document to search
• query (required) — the search string or regex pattern
• regex (optional, default false) — treat query as a regular expression
• case_sensitive (optional, default false) — match case exactly

Returns a list of matches with line numbers, line content, match positions, and matched text. Use this to preview what will be affected before making replacements.

document_replace_text

Targeted find-and-replace within a document. Parameters:

• surface_id (required) — the document to modify
• find (required) — the search string or regex pattern
• replace (required) — the replacement string (supports $1, $2 backreferences when regex is true)
• regex (optional, default false) — treat find as a regular expression
• case_sensitive (optional, default false) — match case exactly
• max_replacements (optional) — limit the number of replacements made

Returns the number of replacements made and whether the content changed.

Workflow

1. Call document_find to preview matches and confirm the pattern is correct.
2. Call document_replace_text to apply the changes.

Examples:

• Fix a recurring typo: Find "recieve", replace with "receive".
• Rename a term throughout: Find "widget" (case-insensitive), replace with "component".
• Reformat dates with regex: Find (\d{2})/(\d{2})/(\d{4}) with regex: true, replace with $3-$1-$2 to convert MM/DD/YYYY to YYYY-MM-DD.
• Swap or reorder sections: Use document_read to get the content, identify the sections to swap, then call document_replace_text to replace the first section with the second and vice versa. For complex rearrangements, use multiple document_replace_text calls with max_replacements: 1.

Comments

Users can leave inline comments on documents. Open comments are surfaced in a <document_comments> context block so you can see pending feedback.

• comment_list — Lists open comments on a document by surface_id. Use this to check for feedback before or after editing, especially when the user asks you to address comments.
• comment_resolve — Marks a comment as resolved by comment_id. Use this after you have addressed the feedback in the document content. Always edit the document first, then resolve the comment.
• comment_reply — Posts a reply to an existing comment by comment_id. Use this to ask clarifying questions or explain why you made (or declined) a change before resolving.

Addressing comments workflow

1. Read the <document_comments> block or call comment_list to see open comments.
2. For each comment, edit the document to address the feedback.
3. Call comment_resolve on comments you have addressed.
4. If a comment is ambiguous, call comment_reply to ask for clarification instead of guessing.

Anti-Patterns

• Don't use app_create for blog posts, articles, or written content. Use document_create — apps are for interactive content with state/data.
• Don't write the article into the chat response. Long-form prose goes in the document editor via document_create, not in chat and not into a .md file in the workspace. Acknowledge what you're doing and stream to the editor.
• Don't wait to generate everything before sending. Stream content in chunks via document_update with mode: "append" so users see progress in real time.

Usage Notes

• The mode parameter on document_update defaults to append.
• Documents are automatically saved and accessible via the Generated panel.
• Users can manually edit documents at any time.
• Write in clear, engaging prose. Use active voice, vary sentence structure, and break content into logical sections with descriptive headings.