← Back to glossary

Tool Use

Araç kullanımı

D3 · Prompts, context, RAG, tools and agents

Tool use is an application pattern in which a model’s output is used to select or call a configured function or external capability and process its result; provider documentation may call this function calling or tool calling.

Review status: 2026-11-26

Technical explanation

A system can process a model-produced function or tool request, execute the selected configured function, and return the result as input for a later model step.

Conceptual boundaries

Tool use is not an autonomous agent by itself; the cited loop only establishes function selection, execution, and result return. Function calling and tool calling are provider interface names, not evidence of a shared cross-provider protocol.

Provider-neutral example

A travel assistant calls a weather service before suggesting what to pack.

Limitations

Tool-enabled systems add security and downstream-action risks, especially when model output can reach external systems or untrusted data sources. A structured call or schema-conforming arguments do not establish that the requested action is authorized, safe, or factually appropriate.

Related concepts

Atomic claims and evidence

  1. 1.1NIST AI 100-2e2025, Adversarial Machine Learning: A Taxonomy and Terminology of Attacks and Mitigations
    Source
    NIST AI 100-2e2025, Adversarial Machine Learning: A Taxonomy and Terminology of Attacks and Mitigations
    Source role
    Authoritative source
    Exact locator
    Section 3.5 printed p. 54: model output, function call, and results returned in next prompt
    Supported claim
    NIST describes LLM-based agents as processing model output to select and call a function with specified inputs and returning results as part of a subsequent prompt.
    Last verification
    Review due
    Scope limitation
    This describes an agent tool-call loop and does not require every tool-enabled application to be an agent.
  2. 2.1NIST AI 100-2e2025, Adversarial Machine Learning: A Taxonomy and Terminology of Attacks and Mitigations
    Source
    NIST AI 100-2e2025, Adversarial Machine Learning: A Taxonomy and Terminology of Attacks and Mitigations
    Source role
    Authoritative source
    Exact locator
    Section 3.5 printed p. 54: tool-enabled agent security risks
    Supported claim
    When agents can take actions using tools, prompt-injection attacks can create risks such as arbitrary-code execution or data exfiltration.
    Last verification
    Review due
    Scope limitation
    This is a threat statement about vulnerable designs and does not establish that every tool call causes harm.
  3. 3.1OpenAI API, Function calling
    Source
    OpenAI API, Function calling
    Source role
    Authoritative source
    Exact locator
    Function calling guide: ‘A function call or tool call’ definition
    Supported claim
    OpenAI uses both “function call” and “tool call” for a model response that requests an available tool, while Anthropic describes tool use as also called function calling.
    Last verification
    Review due
    Scope limitation
    These are provider documentation names for related interface patterns; they do not prove an identical protocol, execution model, or safety property across providers.
    3.2Anthropic API, Tool use with Claude
    Source
    Anthropic API, Tool use with Claude
    Source role
    Authoritative source
    Exact locator
    Tool use overview: ‘Tool use (also called function calling)’
    Supported claim
    OpenAI uses both “function call” and “tool call” for a model response that requests an available tool, while Anthropic describes tool use as also called function calling.
    Last verification
    Review due
    Scope limitation
    These are provider documentation names for related interface patterns; they do not prove an identical protocol, execution model, or safety property across providers.