James W. Niu

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Four Forward Deployed Engineer tasks. An MCP server over stdio with strict validation, an MCP security gateway with role based tool filtering, a streaming PII redaction guardrail, and a token aware rate limiter with model failover on sqlite. Python, 267 tests, no network needed.

Agentic RAG and text-to-SQL over an insurer's claims, policy documents and OCR'd scans. Each query runs as the asker's own Postgres login under row-level security, and a verifier traces every figure and citation. 0 leaks in 84 permission runs, 0 of 34 held-out answers wrong. FastAPI, pgvector hybrid search, Tesseract, React, OpenTelemetry, Claude.

Ask plain questions about customer feedback. Finds urgent issues, themes to escalate and at-risk accounts, each backed by a verbatim quote. Python, FastAPI, CLI chat.

End-of-turn detection for voice agents. Fine-tuned DistilBERT, int8 on CPU at threshold 0.42, 0.949 PR-AUC on a frozen 53-card human gold set, no false speaks on its 27 wait cards, and 0.913 on 96 held-out real-call turns, speaking over 11 of 47. Three referees, gold, regressions and real calls. 33.1 ms end-to-end p95 at concurrency 8.

A service that reports how a GitHub repository reviews its own work, with an LLM narrative whose every number is checked back against the computed metrics