Wow, cool stuff. I never used AgentTCL or D'Agents for anything, but I became aware of both sometime last year and spent a little time reading up on the whole thing. I believe there was a chapter specifically on AgentTCL in one of the books I read.

In some ways, it's a shame it didn't catch on, but the security / access control issues you mention certainly make a lot of sense. That seems to be the big issue that derailed most, if not all, of the various "mobile code" initiatives over the years.