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gpt-5-4 is the GPT-5 production workhorse — mid-tier on the price curve, full feature coverage. Reach for it when you want the GPT-5 family’s reasoning capability and tighter structured-output validation at a mid-tier rate. Pricing: 2.50/1Minput,2.50 / 1M input, 15.00 / 1M output, $0.25 / 1M cache read — see the rate card.

Protocols

The Responses API is the newer agent-style protocol — Codex requires it. Chat Completions is the ubiquitous default; most code will use this one.

Quickstart

Capabilities

When to use

  • Production workhorse — when you need the GPT-5 quality envelope with vision + tools + reasoning, at a mid-tier price.
  • Structured outputs. response_format: { type: "json_schema" } returns schema-validated JSON; ByteSpike does not modify the schema.
  • Codex-style clients. Hit the Responses API instead of Chat Completions for the structured-reasoning shape.
  • Fresh-fact queries. Add tools: [{ "type": "web_search" }].
When not to use:
  • Flagship reasoning — use gpt-5-5, the current GPT-5 family flagship.
  • High-volume classification — gpt-5-4-mini is cheaper.

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