Microsoft Agent 1.5

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Microsoft Agent
Screenshot of the Properties menu in Microsoft Agent 1.5.
NameMicrosoft Agent 1.5
Initial releaseSeptember 8th, 1997 (26 years ago)
Latest version1.5.2.416
Latest version release dateFebruary 20th, 1998 (26 years ago)
Written inC++
Operating systemMicrosoft Windows

Microsoft Agent 1.5 is the first public release of Microsoft Agent. It is an upgrade to beta versions of Microsoft Agent, and dropped compatibility for characters created in the beta version. It replaced using multiple files for a character with a single ACS file that would be used for characters. It also simplified the API for developers and changed all mentions of "AgentX" to "MSAgent" or "AgentSvr". Microsoft Agent 1.5 also installed itself in the Program Files/Program Files (x86) directory. It's character folder was also named "Characters" instead of "CHARS", which is the name of the character folder in Microsoft Agent 2.0.


Not much information is known about the development of Microsoft Agent 1.5, since Microsoft Agent 1.5 was added in Windows 98 build 1569 and removed in Windows 98 build 1624. The only four versions known to exist are build, 225, build 232, build 302, and build 416. Build 225 is the earliest build of Microsoft Agent 1.5 and was compiled on August 18th, 1997. This version was included in the Microsoft Agent Development Kit to help developers at the time include Microsoft Agent in their software before the download went public and was also included in Internet Explorer 4 so that developers can already have it used as an ActiveX control on their website. Build 416 is the latest known build of Microsoft Agent 1.5 and fixes many bugs and exploits from the initial release while also updating the copyright date from 1996-97 to 1996-98.


Many exploits were discovered with Microsoft Agent 1.5 characters that allowed for remote code execution. Microsoft quickly fixed this with a patch in Microsoft Agent 2.0 and also warning users whenever a program or website was trying to load a Microsoft Agent 1.5 character. It is believed that this only applied to Microsoft Agent 1.5 build 232, which meant the latest build of Microsoft Agent 1.5 was unaffected by the exploit.


Build Number Earliest compilation date Source Notes/Issues Link
Microsoft Agent August 13th, 1997 Windows 98 build 1569 Earliest available build of Microsoft Agent 1.5 x86-32 version
Microsoft Agent August 20th, 1997 Internet Explorer 4, Microsoft Agent Development Kit, Windows 98 build 1577 First public build of Microsoft Agent 1.5 msagent232.exe x86-32 version
Microsoft Agent October 29th, 1997 Unknown Unknown, build's existence confirmed by Microsoft Agent Character Editor build 302. N/A
Microsoft Agent February 20th, 1998 VB6 installer & Microsoft website Bug fixes, updates the copyright year MSAGENT416.EXE x86-32 version


  • Microsoft Agent 1.5 came pre-installed on Windows 98 builds 1569 through 1577 before being removed for an unknown reason.
  • Not all Microsoft Agent builds are available in Windows betas as it appeared that Microsoft only occasionally updated the Microsoft Agent after each build. This is also why some builds may contain the same version of Microsoft Agent before the version number changes again.
  • Unlike the 2.0 installer, the Microsoft Agent 1.5 installer has 2 known versions, therefore meaning the installer was updated at least once.