xAI Releases Grok Skills and Updates Tool Calling Responses API

xAI released Grok Skills with enhancements to the Responses API for Grok 4.3. Persistent custom expertise can be created once and retained across conversations on the web platform, iOS app, and Android app. Skills are defined through natural language descriptions or file uploads, and Grok applies workflows, preferences, and document-handling routines automatically in future sessions. Built-in skills support Word document generation and editing with preserved structure, PowerPoint-style slide deck creation with speaker notes, Excel spreadsheet creation with formulas and charts, and PDF creation, merging, splitting, text extraction, and reorganization. Skills operate at the account level, take priority over default behaviors when invoked via slash commands, and can be shared between users. The Responses API supports tool calling with OpenAI-compatible formatting plus native server-side execution for built-in tools, and custom functions defined via JSON schemas.

"xAI has released Grok Skills together with enhancements to the Responses API for Grok 4.3, enabling persistent custom expertise that the model retains across all conversations on the web platform, iOS app, and Android app. Users create these skills once through natural language descriptions or file uploads, after which Grok applies the defined workflows, preferences, and document-handling routines automatically without needing repeated instructions in future sessions."

"The built-in capabilities cover full generation and editing of Word documents that preserve headings, tables, and styles, creation of PowerPoint-style slide decks that include visual hierarchy and speaker notes, Excel spreadsheets that support formulas, data analysis, charts, and conditional formatting, and PDF operations that allow creation, merging, splitting, text extraction, and content reorganization. These skills operate at the account level, take priority over default behaviors when invoked via slash commands, and support sharing between users for collaborative setups."

"On the developer side, the Responses API integrates these concepts through tool calling that follows an OpenAI-compatible format while adding native server-side execution for built-in tools. Developers include tools in API requests by specifying types such as web_search, x_search, or code_interpreter for automatic handling on xAI infrastructure, or define custom functions using JSON schemas that describe name, description, and parameters."

"When Grok 4.3 determines a tool is needed, it returns structured tool_call objects with call identifiers and arguments. Client applications then execute the logic locally, append the results as tool outputs in the next request, and continue the conversation loop. The model supports parallel tool calls by default, handles up to 128 tools per request, maintains a 1 million token context window, and produces outputs suited for multi-step agentic tasks."

Read at InfoQ