GPT-5.4 vs Inkling

Choose GPT-5.4 if you want…

• ✓Higher intelligence (Artificial Analysis index 51)
• ✓Larger context window (1.1M)

Choose Inkling if you want…

• ✓Lower price ($1.76 / 1M blended)

GPT-5.4

GPT-5.4 was built for the actual work that happens inside offices — financial modeling, legal analysis, complex codebases, and multi-step document workflows — rather than for chasing narrow benchmarks. That strategic shift shows in the numbers: it matched or outperformed human professionals in 83% of head-to-head comparisons, and developers have called its coding output "flawless," with some declaring it the definitive choice for complex software engineering work. Native computer-use capabilities let it operate browsers and desktop apps directly, and it scored above the human baseline on UI interaction tasks. The 1.05 million token context window handles large codebases and lengthy legal documents in a single pass, though you need to configure it explicitly — the default is 272K. Where GPT-5.4 falls short is nuance: it tends to interpret requests too literally, missing the intent behind ambiguous prompts in ways that Claude handles more naturally. Writing personality is another common frustration, with verbose follow-up suggestions that can feel mechanical. For structured professional tasks where thoroughness and tool integration matter more than prose feel, it is the strongest model in the GPT-5 line prior to the release of GPT-5.5.

Inkling

Inkling is Thinking Machines Lab's first open-weights model, and on just4o.chat it runs through the Vercel AI Gateway under thinkingmachines/inkling. It is a multimodal MoE with 975B total parameters and 41B active, trained to reason over text, images, and audio in a shared space rather than bolting on separate encoders. Controllable thinking effort lets you trade latency for depth, function calling supports agentic workflows, and a 256k context window on the gateway is roomy enough for long multimodal sessions. It is a base-tier model on just4o.chat, billed at 4 base requests per send before length multipliers, at $1.00 per million input and $4.05 per million output tokens (cached input $0.17). Practical caveats: no native web search on this route, and chat attachments currently emphasize image input even though the model itself understands audio. For teams that want an open, customizable multimodal foundation with ZDR-compatible gateway routing, Inkling is a strong addition.