@hlao-mcp/appsheet

MCP server that wraps the Google AppSheet REST API and exposes it as typed tools for HLAO agents.

What this MCP connects to

AppSheet is Google's no-code app platform; this server lets an agent read and write rows in any AppSheet-backed table the credentials authorize.

Tools

Read tools (safe; do not mutate AppSheet state):

| Tool | What it does | | --------------- | ------------------------------------------------------------------ | | find_records | Find rows in a table by key or by AppSheet selector expression. |

Write tools (mutate AppSheet; require HLAO authority gate):

| Tool | Required passport scope | What it does | | ---------------- | ------------------------------- | ----------------------------------------------------- | | add_record | appsheet:add_record | Add a new row to a table. | | update_record | appsheet:update_record | Update an existing row by key. | | delete_record | appsheet:delete_record | Delete a row by key. | | invoke_action | appsheet:invoke_action | Run a predefined AppSheet action against rows. |

All write tools are gated through the HLAO passport: a missing or under-scoped passport returns a structured gate_required / gate_denied error before any upstream call is made.

Credentials

| Variable | What it is | | ---------------------- | ---------------------------------------------------------------------------- | | APPSHEET_APP_ID | AppSheet application id (UUID). Required. | | APPSHEET_ACCESS_KEY | Application Access Key (sent as header ApplicationAccessKey). Required.| | APPSHEET_LOCALE | Optional locale (default en-US). | | APPSHEET_TIMEZONE | Optional timezone (default Pacific Standard Time). |

How to get credentials

Plan requirement: AppSheet API access requires the Core plan or above. Confirm your AppSheet workspace is on Core or higher before generating keys.

1. Open your app in the AppSheet editor.
2. Manage → Integrations → IN (incoming): enable the IN section.
3. Click Create Application Access Key and copy the key.
4. The App ID is shown on the same Manage → Integrations page (or in the app's URL).
5. Store both in your .env (this directory).

Local development

cp .env.example .env
pnpm install
pnpm --filter @hlao-mcp/appsheet build

# Streamable HTTP (production-shaped)
HLAO_MCP_HTTP_PORT=3002 node dist/server.js

# stdio (for local MCP-client testing)
HLAO_MCP_TRANSPORT=stdio node dist/server.js

HLAO wrapping

The HLAO @hlao/mcp-gateway calls this server with the verified passport forwarded as x-hlao-authority (JSON). The server uses that header to gate all write tools; the gateway logs every call through the audit substrate.