The problem was solved once before — in 1995.
TeleKey revives a single idea from Telescript, General Magic's mobile-agent language, and distills it to one rule. Here's the idea, the paper it came from, and the people who built it three decades before the agent era arrived.
The idea we're drawing on
Telescript's Permit
Telescript agents were programs that travelled — moving from one machine (a "place") to another to do their work. The danger is obvious: code arriving from elsewhere, running on your machine, reaching for your resources. Telescript's answer was the permit — a set of attributes, enforced by the runtime engine, that defined exactly what an agent was allowed to do.
A permit carried both capabilities (what the agent may do) and allowances (how much it may consume, measured in "teleclicks"):
The part TeleKey builds on: an agent's effective authority was the intersection of the permit it carried with the permit of the place it entered. Authority could only ever be reduced at each boundary — never increased. Cross a boundary, and your permit narrows. It cannot widen.
That "only-ever-narrows" property — enforced by a trusted engine sitting between the agent and everything it touches — is the direct ancestor of TeleKey's one rule: a delegated key is valid only if caps ⊆ parent. We didn't invent the idea. We distilled a 1995 one to a single invariant and put it where MCP agents run today.
Primary sources: An Introduction to Safety and Security in Telescript (General Magic) and the Telescript Language Reference (October 1995).
One of the most important dead companies in Silicon Valley
General Magic spun out of Apple in 1990 to build the handheld communicator its founders could already see coming. The roster was staggering: core architects of the original Macintosh, alongside people who would go on to create the iPhone (Tony Fadell) and Android (Andy Rubin). By 1991 they were already building the smartphone, the app store, e-commerce, streaming, and software agents — and had to invent softmodems and touchscreen chips just to demo it.
They were roughly fifteen years early. The networks weren't there, the devices weren't there, the market wasn't there. The company folded in 2002. Forbes later called it "the most important dead company in Silicon Valley." The ideas didn't die — they scattered into the products that came to define the era that followed.
The agent-authorization problem Jim White wrote about in 1995 — running code safely across trust boundaries you don't control — is the exact problem MCP agents face today. Right idea. Wrong decade. Finally on time.▶ Watch the story General Magic (2018) — the documentary, built from footage shot inside the company in the '90s. ↗
The people who built it
Roles as stated in Jim White's 1995 white paper, "Mobile Agents." Telescript role first; earlier and later work below.
Invented and commercialized the mobile-agent paradigm; oversaw US Patent 5,603,031 describing mobile agents; authored the four Telescript white papers. A long career in networked-agent and identity systems followed.
University of Illinois EE. Later founded Guardian Analytics, an online-fraud-prevention company — a security career that rhymes with the permit work. Now in engineering leadership in the Bay Area.
One of the leads who conceived Telescript and implemented it for servers, per White's paper.
A core architect of the original Macintosh. Later at Google, where he worked on the design of Google+ and Circles.
Technical lead for Apple's System 7. Later a long tenure at Apple as an engineering manager on Safari and WebKit.
Read further
- 1995White, J.E. — "Telescript Technology: Mobile Agents" (white paper #4)
- 1995"An Introduction to Safety and Security in Telescript" — the permit model
- 1995Telescript Language Reference (bitsavers)
- wikiGeneral Magic · Telescript (programming language)
- 2011"The Most Important Dead Company in Silicon Valley?" — Forbes
- 2018General Magic — the documentary
Some 1990s links are served from community archives and may occasionally be down; the Wayback Machine holds copies of each.