Browse older CallSphere articles on AI voice agents, contact center automation, and conversational AI.
From the blog
Every coding agent has to pick a model. With GPT-5.5 winning Terminal-Bench and Opus 4.7 winning SWE-bench Pro, the agent stack you pick affects which model you get.
Where you can buy each model matters as much as benchmarks. Opus 4.7 launched on Bedrock, Vertex, and Foundry day-one; GPT-5.5 enterprise distribution is Azure-centric. Here is what that means for procurement.
Both vendors invest heavily in safety post-training. The differences show up in refusal behavior, prompt-injection resistance, and how each handles agentic edge cases.
Both models stream tokens. The differences in time-to-first-token, tokens-per-second, and total-task-latency change which one wins for which workload. A practical breakdown.
GPT-5.5 ships natively omnimodal with Realtime API. Opus 4.7 is text-only — voice means STT + Opus + TTS. Here is the production trade-off for voice agent teams.
GPT-5.5 ships natively omnimodal — text, image, audio, video in one model. Opus 4.7 brings substantially better vision resolution. The strengths point in different directions.
GPT-5.5's biggest under-the-hood change is output token efficiency. Here is what that means for cost, latency, and how you should architect prompts for both models.
Both models are excellent at function calling. The differences are in error recovery, schema strictness, and how each handles concurrent tool calls. A production-focused comparison.
GPT-5.5 leads FrontierMath Tiers 1-3 at 51.7%; Opus 4.7 leads GPQA Diamond at 94.2%. Two of the hardest reasoning benchmarks point in different directions. Here is why.
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