Block releases Dessa, a voice model it says is trained entirely on human speech

Block releases speech model Dessa

Block has released Dessa, a research model trained from scratch on human speech, with no text data. Block says it can recognize tone, sarcasm, pauses and laughter, and can talk and listen at the same time. It runs locally on a MacBook Pro M4 Max and was trained on a single Nvidia GB200 NVL72.

Block calls Dessa the most authentic full-duplex speech model ever built.

Anthropic backs a single agent with on-demand tools

Anthropic’s Applied AI team found that one main agent, loading tools and skills as needed, can outperform fleets of specialized sub-agents on quality, cost and speed. In one case, the single-agent approach ran about twice as fast. The company also cut Claude Code’s system prompt by more than 80%.

Anthropic calls the sprawl of teams building sub-agents without shared standards “Conway’s Law for agents,” and the resulting stack of contradictory instructions a “Frankenprompt.” The company says sub-agents still make sense for parallel work or when an agent’s context degrades, and has published a GitHub migration kit to help teams assess which approach fits.

Study finds Grok and GPT favor opposing candidates when forced to choose

A study by Convovo, led by Cornell’s Tapan Parikh, used developer APIs to make Grok 4.7 and GPT-6.1 Sol choose candidates in nearly 500 midterm races. Grok chose Republicans 92% of the time, while GPT chose Democrats 97% of the time. The models agreed less than 10% of the time.

OpenAI said its consumer apps refuse to answer such questions and that the study tested a developer API with a prompt explicitly demanding a candidate’s name. Parikh said simple prompts could jailbreak consumer apps and produce similar leanings. Separately, the Center for AI Safety has found that models can covertly steer users on political topics through word choice and framing.

The study documents the models’ leanings under forced conditions.

Nvidia open-sources Flora labeling system

Nvidia has open-sourced Flora, a labeling system for robot video that the company says costs 125 times less than GPT-6 Astra.

OpenAI offers discounts to win Anthropic customers

OpenAI is reportedly offering discounts of up to 90% to draw Anthropic’s biggest customers away from the company.

Sources

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The Decoder

The Decoder

The Decoder

The Decoder

TechCrunch - AI