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Function calling lets a model request a named operation. Your application or Dreamtune’s local agent decides which configured binding can execute it. A function definition does not grant the model unrestricted tool access.

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Before you begin

  • Choose a catalog model that supports function calling.
  • Give the key model access and access to the tools you will execute.
  • Inspect each tool’s actual input schema.
  • Persist a distinct operation key for every intended model and tool submission.

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Define a function

Include tools on the model request. A definition uses this shape:
This defines a function contract. It is not itself a catalog connector. Map its arguments to an explicitly authorized tool or your own application function. tool_choice accepts auto, none, required, or a named function selection. parallel_tool_calls is optional. These options require tools; a named selection must refer to one of the supplied definitions.

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Complete the conversation

  1. Read run.message.tool_calls when the model requests functions.
  2. Preserve the complete assistant message, including reasoning_details if present. A tool-only assistant message can have null content.
  3. Validate each function name and parsed arguments against your allowed bindings.
  4. Execute authorized operations and append a role: "tool" message for each returned call ID.
  5. Submit the next model request with the accumulated messages and the same tool definitions, using a new saved model-operation key.
Every requested call needs exactly one matching result before the next ordinary conversation message. Do not invent call IDs, discard reasoning fields or append unrelated tool results. Text-only conversations end with a user turn; a function round can end with its complete set of tool results.

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Bound the loop

Limit operation count, output size, elapsed time and spend in your application. Treat fetched content as data rather than instructions. A completed model turn and each successful tool operation settle independently. For a ready local loop, see the tool-calling agent tutorial.