google-docs-mcp

README

google-docs-mcp

A production-grade Model Context Protocol server for Google Docs, written in Go. It lets Claude Code, Claude Desktop and any other MCP client work inside a Google Doc the way a careful colleague does: read it at the right granularity, edit it in place without damaging what is around the edit, propose changes as suggestions, comment on passages, and handle tables, tabs, headers, footnotes and formatting.

Single static binary. Per-user OAuth against your own Google account, in your own Google Cloud project. Nothing leaves your machine except calls to Google's APIs.

Status: Phase 3 done (v0.3.0). Reading, searching, creating, exporting, editing with minimal diffs in suggest, direct or comment mode, formatting, reviewing suggestions, comment threads, revision history and diffs, tables, tabs, headers, footers, footnotes, images, chips, gdocs:// resources, large-document performance and agent evals are in; see docs/architecture.md for the design and what the evals found.

Why another Google Docs MCP

Existing servers hand the model raw UTF-16 indices, convert markdown in ways that silently corrupt documents, and anchor comments through the Drive API where they never render inline. This server keeps index math on the server, addresses content by exact text and stable heading ids, edits by minimal diff, refuses to overwrite anchored content, and uses the Docs API's suggestion mode where the project is enrolled. The reasoning and evidence are in docs/architecture.md.

Install

Download a binary from the releases page, or:

go install github.com/mmedum/google-docs-mcp/cmd/google-docs-mcp@latest

Set up Google (once per person)

Every deployer uses their own Google Cloud project and OAuth client. There is no shared app and nothing to verify with Google.

1. Create or pick a Google Cloud project.
2. Enable the Google Docs API and the Google Drive API (APIs & Services → Library).
3. Configure the OAuth consent screen (Google Auth Platform → Audience):
   • Internal if your account is in a Google Workspace organisation. Tokens then never expire.
   • External with publishing status Testing for a consumer account. Add yourself as a test user. Google expires refresh tokens for such apps after 7 days, so you will run login weekly.
4. Add scopes (Google Auth Platform → Data Access): .../auth/documents, .../auth/documents.readonly, .../auth/drive, .../auth/drive.readonly.
5. Create an OAuth client (Google Auth Platform → Clients) of type Desktop app, download its JSON, and store it as ~/.config/google-docs-mcp/client_secret.json (Linux; the google-docs-mcp folder under your OS config directory elsewhere). Keep it out of any repository.
6. Run:

google-docs-mcp login
google-docs-mcp doctor https://docs.google.com/document/d/<some doc you can open>/edit

login opens a browser, completes Google's desktop OAuth flow on a loopback port, and stores the refresh token in your OS keyring (Secret Service, Keychain or Credential Manager), falling back to a 0600 file with a warning when no keyring is available. doctor checks every step and tells you exactly what is missing.

Optional: Developer Preview

Suggestion mode (mode: suggest), comments anchored to a text range, and accepting or rejecting suggestions use Docs API features that are in the Google Workspace Developer Preview Program. Apply with the form on that page, giving your Cloud project id. Once enabled for your project, set GDOCS_PREVIEW=true. The programme terms allow use inside your own organisation; do not offer a preview-enabled deployment to people outside it.

Connect a client

Claude Code:

claude mcp add --transport stdio google-docs -- google-docs-mcp

Claude Desktop (claude_desktop_config.json) or Cursor (mcp.json):

{
  "mcpServers": {
    "google-docs": {
      "command": "/absolute/path/to/google-docs-mcp",
      "env": { "GDOCS_LOG_LEVEL": "info" }
    }
  }
}

All settings are environment variables; see docs/configuration.md. Nothing needs to be set for the defaults.

Tools

Tool	What it does
get_document	Title, tabs, revision id, owner, last change, counts, and this server's capabilities (available write modes, default). Cheap; call it first.
get_outline	Heading tree per tab with stable heading_ids, block handles, and section sizes.
read_document	Scoped, budgeted read as markdown, plain text, or raw Docs JSON. Scope by heading_id, heading text, handle range, tab, or header/footer/footnote. Options show handles, styles, pending suggestions as {++inserted++} / {--deleted--}, and comment markers {>>c:id<<}.
find_in_document	Text or regex search returning handles, offsets and context.
search_documents	Locate documents by title or content, owner, or modification date.
export_document	Google's own md, txt, html inline; pdf, docx, odt, rtf, epub as files under GDOCS_EXPORT_DIR.
create_document	New document, optionally with markdown content.
edit_document	Atomic batch of insert, append, replace (minimal diff), delete, replace_all, insert_break, insert_footnote, create_header, create_footer, delete_header, delete_footer. Targets are exact text, heading_id, handles or cells. mode: suggest, direct or comment; dry_run; expect_revision; force.
format_document	text_style, paragraph_style, bullets, clear_formatting on the same targets, same modes.
list_suggestions	Pending suggested edits with ids, text and handles.
review_suggestion	Accept or reject suggestions by id or all (Developer Preview).
list_comments	Comment threads with every reply, resolved and deleted state, quoted text and the block they sit on.
add_comment	Comment on a passage (pinned with Developer Preview, quoted otherwise) or on the document.
reply_comment	Reply to, resolve or reopen a thread.
list_revisions	Version history: revision ids, times, authors.
diff_revisions	Unified diff of Google's markdown or text export between two revisions. read_document reads an old revision whole.
edit_table	insert_table (with a data grid), set_cells (minimal diff per cell), insert_rows, delete_rows, insert_columns, delete_columns, merge_cells, unmerge_cells, style_cells, pin_header_rows. Same modes and guard as text edits.
insert_object	Inline image from a public URL, person chip, rich-link chip, or date chip at a location.
manage_tabs	Add (with content), rename, move or nest tabs. Always direct: the API cannot suggest tab changes.

Two more tools register only with GDOCS_ENABLE_DESTRUCTIVE=true: delete_comment (a thread or one reply) and delete_tab (a tab with its content and child tabs). Both carry the destructive annotation and ask the client to involve the person.

Documents are identified by id or any docs.google.com URL.

Resources

Clients that attach context as MCP resources can read a document without a tool call. Each is markdown with no handles, suggestions or comments; the read tools are for scoped, budgeted reads.

• gdocs://<id> — every tab's body, cut at 400000 characters with a note saying where read_document can continue.
• gdocs://<id>/outline — the heading tree get_outline returns.
• gdocs://<id>/tabs/<tab> — one tab's body; tab is an id, title or number.

How edits are addressed

The model never sees index numbers. A target is exact text quoted from a read (curly quotes, dashes and spacing are normalised; it must occur once, or occurrence / within disambiguates), a whole section by its stable heading_id, a block by handle (p12, valid for the revision it came from and re-checked on use), or a table cell. New content is written as markdown. A replace is applied as the smallest diff between the old and new text, so untouched words keep their formatting and anchored comments.

Tables are named by handle (tbl1) and cells as r2c3; a table that gets a data grid is inserted empty and filled in a second batch once it exists. Old revisions are read and diffed through Google's export, so they have no handles.

Safety model

• Read tools are annotated read-only. Write tools take a mode chosen by the person: suggest (tracked change), direct, or comment (the proposal is posted as a comment and nothing is edited). Every write is guarded by the revision it was planned against; a concurrent edit is re-planned once, then refused.
• Direct edits never delete a range that holds a comment anchor, a pending suggestion, an image or a footnote unless explicitly forced.
• Destructive tools (deleting comments or tabs) are not registered unless GDOCS_ENABLE_DESTRUCTIVE=true. GDOCS_READ_ONLY=true registers only read tools and requests read-only scopes.
• The server talks only to Google (googleapis.com, and docs.google.com for the revision export links Google's API returns). No telemetry. Logs (stderr) never contain document text.
• Refresh tokens live in the OS keyring; logout revokes and deletes.

See docs/security.md.

Development

make check      # gofmt, vet, golangci-lint, tests with coverage floor, govulncheck, stdio smoke
make build
./google-docs-mcp --dump-schemas

Test fixtures are synthetic. Never add content, ids or URLs from real documents; gitleaks runs in pre-commit and CI. make bench measures the large-document paths; scripts/evals/run.py runs the agent evals against your own account (see its header).

Licence

Apache-2.0.