Build notes / architecture / field tests
Technical notes from building PromptFax across the web, MCP hosts, payment infrastructure, document storage, and a fax network that still speaks in tones.
ChatGPT WebMCP / implementation
ChatGPT supports top-level JavaScript tools, not every WebMCP API. This implementation guide covers browser uploads, asynchronous completion, durable state, human controls, cleanup, and testing.
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MCP / file intake
Why chat attachments are not portable document inputs, and how PromptFax now combines strict ChatGPT file parameters, immediate import, MCP Apps, and explicit fallbacks.
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AI agents / web apps
A short PromptFax recap of what worked across in-app chat, browser control, MCP, MCP Apps, WebMCP, and Custom GPTs—with full details on cogint.ai.
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