ChatGPT Plugin

Letter.md

Review Markdown with AI

Brand: Letter.md

Category: Productivity
Primary Subcategory: Collaborative Docs & Workspaces

Integration details

Description

Letter.md lets people read, search, and review Markdown documents from ChatGPT. It can create traceable comments and reviewable edit suggestions, inspect document images, compare versions, and open the complete realtime collaborative editor. With an explicit user request and publication permission, it can publish a document or update its public page; publishing never changes the private source document automatically. Users can also save generated Markdown as a new unpublished document in a writable Letter.md workspace or create a derivative document. Access is limited to the workspaces and scopes approved through OAuth.

Integration type: Plugin
Verification status: Not applicable
Platform: ChatGPT
Category: Productivity
Primary Subcategory: Collaborative Docs & Workspaces
Secondary Subcategories: None listed
Brand: Letter.md
Access: Account required
First tracked: 2026-10-13
Tool count: 35
Market: US

Agent DiscoverabilityChatGPT Plugin Discovery Score

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Primary Subcategory

Competing in ChatGPT Collaborative Docs & Workspaces

View Category

Listed in alphabetical order

Primary Subcategory

Abilitya AssistantComing soonGet notified

Accelflow SpaceComing soonGet notified

ArtifactBridgeComing soonGet notified

AttachPageComing soonGet notified

CaipiComing soonGet notified

Letter.mdComing soonGet notified

Tools

35 tools agents can invoke

Create categorized, anchored Codex findings as review comments. This never edits document content.
create_review_findings
Add a traceable Codex comment anchored to a requested selection. This does not edit document content.
create_agent_comment
Create a comment thread on the current selection in the mounted editor.
create_widget_comment
Read the current document and one saved version for a read-only change summary.
get_document_version_context
Use this only for an active in-editor derivative workflow. Creates a new Markdown document beside the source and never overwrites it. For an ordinary conversation save, use create_document.
create_document_from_ai
Mark an in-editor AI request as failed when it cannot be completed safely or reliably.
fail_ai_request
Renew the current AI execution lease during a long-running in-editor request.
heartbeat_ai_request
List the documents the linked user can access.
list_documents
List the workspaces the linked user can access.
list_workspaces
List only writable workspaces and their folder names so the user can choose where a new unpublished document will be created. Does not return document content or document metadata.
list_document_create_destinations
List the cloud folder tree for a workspace.
list_folders
Read one private image asset for the mounted Letter.md editor.
get_widget_image_asset
Read private image-document content for the mounted Letter.md editor.
get_widget_image_document
Open the complete collaborative Markdown editor in the current MCP host, with realtime saving and reviewable Agent suggestions. Omit documentId to open the most recently updated accessible document.
render_letter_editor
Publish an unpublished document to the public web only after the user explicitly asks. Call get_publication_context first and pass its current document revision. Use update_document_publication when a public version already exists.
publish_document
Read the latest Yjs-derived Markdown and block structure before creating suggestions.
get_document
Resolve an opaque request created in Letter.md into its primary document, frozen secondary sources, selection, and instruction context.
get_edit_request_context
Read open or resolved review comments as context before creating a traceable suggestion.
list_document_comments
List image assets referenced by a document for alt-text and caption review.
get_document_assets_context
Read the current Markdown together with unresolved comments for a traceable review task.
get_review_context
Read document content and existing publication metadata without publishing or changing it.
get_publication_context
Read open and resolved comment threads for the mounted Letter.md editor.
list_widget_comments
Read pending suggestions for the mounted Letter.md editor.
list_widget_suggestions
Create a short-lived, one-time realtime ticket for the mounted direct Letter.md widget.
create_widget_realtime_ticket
Add a reply to an existing comment thread in the mounted editor.
reply_widget_comment
Set an editor comment thread to open or resolved.
set_widget_comment_state
Complete a read-only in-editor AI workflow with concise structured results for the Letter.md UI.
complete_ai_request
Accept, reject, complete, cancel, or mark a pending editor suggestion as conflicted.
decide_widget_suggestion
Use this only when the user explicitly asks to save Markdown as a new Letter.md document. Creates a separate unpublished document in a writable workspace and never edits or overwrites an existing document. Identical retries are deduplicated automatically when idempotencyKey is omitted. For an active in-editor derivative workflow, use create_document_from_ai.
create_document
Save private image-document content from the mounted Letter.md editor.
update_widget_image_document
Semantically search Markdown the linked user can access. Omit documentId and workspaceId to search every accessible workspace. Results contain short excerpts; use get_document for complete Markdown.
search_workspace_documents
Create a reviewable suggestion. This never edits the document directly.
create_suggestion
Replace an existing public version with the current document and metadata only after the user explicitly asks. Call get_publication_context first and pass both current revisions.
update_document_publication
Store a generated or supplied image in the document asset library. Pass raw base64 or a base64 data URL, then use the returned Markdown with create_suggestion for reviewable insertion.
upload_document_image
Read one image referenced by the current document so its visual content can be reviewed.
get_document_asset

FAQs

Letter.md ChatGPT Plugin FAQ

How the directory, categories and Discoverability Score work.

Read the methodology

How do I improve Letter.md's ChatGPT Plugin discoverability?

The levers are the listing surface agents actually read: names, descriptions, keywords, tool metadata, and registry health. Which lever matters depends on where discovery breaks, which is what continuous measurement shows.

What are Letter.md alternatives on ChatGPT?

As of 2026-11-02, Letter.md competes with Abilitya Assistant, Accelflow Space, ArtifactBridge, AttachPage, Caipi, Clinked, Coda, Descry and 17 more in ChatGPT Collaborative Docs & Workspaces, ranked by public Discoverability Score.

Where is this profile measured?

This profile uses the geography attached to the latest public registry snapshot: US. Locale tags are intentionally omitted.