MCP Tools — Overview

OOS provides Claude with a defined set of MCP tools. These tools are the only interface between Claude and OOS.

Tool List

Tool	Description
oos_schema	Load AST — contexts, fields, prompts
oos_query	Load data and render into Board
oos_render	Render JSON directly into Board
oos_ui_change_required	Write changes as preview into Board
oos_ui_save	Save data
oos_system_status	Get system status
oos_contacts	Load contacts
oos_mail_compose	Prepare a mail
oos_mail_send	Send a mail

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oos_schema

Loads the complete OOS AST and returns it to Claude.

Claude always uses this tool first, before querying or changing data.

Returns:

• All available contexts with fields, types, list_fields
• Global and context-specific AI prompts
• Locales, relations, navigate definitions

Important: The schema is processed internally. Claude does not output raw schema data in the chat.

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oos_query

Loads data via GraphQL and renders it into the Board.

Parameters:

• context — name of the context (e.g. person_list)
• query — GraphQL query string

Example:

context: "person_list"
query:   "{ person_list { id firstname lastname email city age net_worth } }"

Returns: "All data was successfully displayed in the UI."

Rules:

• Always call oos_schema first
• Use exactly the list_fields of the context
• Do not call oos_query without loading the schema first

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oos_render

Renders JSON data directly into the Board — without GraphQL.

Parameters:

• context — context for the HTML template
• json — data as JSON string

Usage: When data is already available (e.g. from an external source) and only needs to be displayed.

context: "person_list"
json:    "[{\"id\":1,\"firstname\":\"John\",\"lastname\":\"Smith\"}]"

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oos_ui_change_required

Writes AI changes as a preview into the Board. Data is not yet saved.

Parameters:

• context — context of the current form
• changes — changed fields as a JSON object

Example:

context: "person_detail"
changes: {"lastname": "Smith", "age": 35}

Workflow: Always after oos_query, always before oos_ui_save.

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oos_ui_save

Saves the current Board data to the database.

No parameters.

OOS automatically scrapes the FormData from the Board, builds the GraphQL mutation, and executes it.

Prerequisite: The user must have explicitly confirmed they want to save.

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oos_system_status

Returns the current system status:

• Active context
• Available tools
• DSN status

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oos_contacts

Loads contacts from the configured provider (CardDAV, Google, Microsoft).

Parameters:

• query — search term (name, email)

Returns: List of contacts with name, email, phone.

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oos_mail_compose

Prepares an email and shows a preview in the Board.

Parameters:

• to — recipient (name or email from contacts)
• subject — subject line
• body — message body

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oos_mail_send

Sends the prepared email from the current session.

No parameters.

Prerequisite: oos_mail_compose was called and the user has confirmed with “send”.

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The Complete AI Workflow

1. oos_schema              → load schema (once per session)
2. oos_query               → load and display data
3. [user wants to change something]
4. oos_ui_change_required  → show changes as preview
5. [user confirms]
6. oos_ui_save             → save