Sign in
Skip to solution
mediumSystem Design

Tool calling vs function calling vs structured output — what changed in 2025?

780 views
01

Understand the problem

From function_call to tool_use to strict JSON mode — model-centric invocation.

tool-callingfunction-calling
02

Attempt it yourself

Sketch your approach before reading the solution — that's what interviews test.

Nudge consolestandby

Stuck? Beam a request up — the console returns a conceptual nudge that guides your logic without spoiling the implementation.

03

Study the solution

Function calling (2023) -> Tool calling (parallel tools, tool_choice) -> Strict structured output (JSON Schema guaranteed). Tool calling runs multiple tools per turn; structured output guarantees shape.

Solution ready — 2 min read

Classified // press E to declassify

04

Join the discussion

Discussion (0)

Sign in to join the discussion.

No responses yet. Be the first to share what you think.

Transmission complete // awaiting log

KEEP THE
STREAK ALIVE.

Dossier 30 of 80 decoded in the AI Engineering track. One more won't hurt.

Back to track