https://joshuafields.uk/blog Technical writing by Joshua Fields, a London-based AI and software engineer, on AI agents, authorization, real-time voice AI and full-stack engineering. en-gb Sun, 25 Oct 2026 09:00:00 GMT https://joshuafields.uk/blog/authorizing-ai-agents-mcp-tool-calls-zanzibar https://joshuafields.uk/blog/authorizing-ai-agents-mcp-tool-calls-zanzibar Sun, 25 Oct 2026 09:00:00 GMT Joshua Fields Joshua Fields, a London-based AI engineer, shows how to authorize AI agent and MCP tool calls with Zanzibar-style ReBAC: delegation, tool grants and per-resource checks in one schema, with transactional revocation and measured latency using pemba. AI engineer AI agents MCP Model Context Protocol agent authorization Zanzibar authorization ReBAC SpiceDB Python AI security London https://joshuafields.uk/blog/building-pemba-embedded-zanzibar-authorization-rust https://joshuafields.uk/blog/building-pemba-embedded-zanzibar-authorization-rust Mon, 19 Oct 2026 09:00:00 GMT Joshua Fields Joshua Fields, a London-based software engineer, on building pemba: an embedded, Zanzibar-style authorization engine in Rust and Python whose permission writes join the application's own SQLite transaction, with SCC fixed-point evaluation for cyclic data and differential testing against SpiceDB. software engineer Rust Python Zanzibar authorization SpiceDB SQLite property-based testing open source London https://joshuafields.uk/blog/building-authorization-infrastructure-spicedb-go-kubernetes https://joshuafields.uk/blog/building-authorization-infrastructure-spicedb-go-kubernetes Mon, 22 Jun 2026 09:00:00 GMT Joshua Fields Joshua Fields, a London-based software engineer, explains how to think about authorization infrastructure using SpiceDB, Zanzibar-style permissions, Go services, Kubernetes, schema-as-code, and production rollout strategy. software engineer SpiceDB Zanzibar authorization Go Kubernetes backend infrastructure AI infrastructure London https://joshuafields.uk/blog/building-real-time-voice-ai-applications-livekit-fastapi https://joshuafields.uk/blog/building-real-time-voice-ai-applications-livekit-fastapi Mon, 22 Jun 2026 09:00:00 GMT Joshua Fields Joshua Fields, a London-based software engineer and creative technologist, explains how real-time voice AI applications can be designed with LiveKit, FastAPI, LLMs, speech-to-text, text-to-speech, and production-grade backend architecture. software engineer London real-time voice AI LiveKit FastAPI LLM applications AI infrastructure https://joshuafields.uk/blog/designing-explainable-ai-matchmaking-systems https://joshuafields.uk/blog/designing-explainable-ai-matchmaking-systems Mon, 22 Jun 2026 09:00:00 GMT Joshua Fields Joshua Fields writes about building explainable AI-assisted matchmaking systems using conversational onboarding, profile enrichment, deterministic scoring, privacy-aware design, and human-centred product thinking. AI matchmaking software engineer creative technologist explainable AI London full-stack AI product https://joshuafields.uk/blog/when-should-governments-pull-the-plug-on-ai-models https://joshuafields.uk/blog/when-should-governments-pull-the-plug-on-ai-models Mon, 22 Jun 2026 09:00:00 GMT Joshua Fields Joshua Fields examines when government intervention in frontier AI may be justified, and why capability-based controls, access design, and infrastructure-level accountability matter for safe deployment. AI policy software engineering AI infrastructure cybersecurity access control