Rex Chang

GenAI & Cloud Solution Architect / Program Lead
I turn AI and cloud technology into business value—and bring teams together to make it happen. Enterprise experience across TikTok Ads, Microsoft Azure, and Tencent Cloud.
Rex Chang

Enterprise Experience

Experience across

TikTok logo
Microsoft logo
Tencent Cloud logo
  • Led cross-functional initiatives within TikTok Ads’ 100+ person organization, improving operational efficiency and issue resolution speed.
  • Delivered multi-million-dollar cloud solutions for enterprise clients at Microsoft and Tencent Cloud.
  • Aligned engineering, product, and business teams around shared priorities in high-velocity, risk-sensitive environments.

Working Demos

AI agents and assistants you can watch or try, each with a walkthrough of how it works.

Escalation call in three steps: the caller mentions a group of 12, the agent flags the request for review and checks availability, and the saved record is marked for specialist review.Live demo + sample calls

Voice AI agent

Voice Intake Agent

Inbound calls pull staff away from higher-value work.

This agent answers routine customer calls, captures each request and checks availability, then flags complex requests for human review with captured context.

Design Principle

Availability comes from your systems, not AI guesswork, and every call ends as a structured record.

Sample call · Escalation

Frame from the FAQ Surge Assistant demo videoDemo video

Multilingual support assistant

FAQ Surge Assistant

Sale days flood support with the same questions.

This assistant answers in the customer’s own language, with sources, and reuses saved answers to repeated questions.

Design Principle

Search each language separately and reuse saved answers to repeated questions.

Result

Repeat answers 100×+ faster in lab benchmarks.

Controlled AI Lead Triage · A lead-triage workflow connecting form intake, AI interpretation, routing rules, CRM records, and human-review alerts.

See the evidence

GenAI System Design Case Studies

Abstracted from real client scenarios and rebuilt as demos to show the design decisions behind each system.

Selected AI systems work across sales, ad review and publishing—with design decisions, evaluation results and supporting materials.

Explore the case studies.

Sales Renewal Drafting Assistant

Keep earlier promises in view when drafting renewals.

Uses deal notes to bring customer preferences, prior commitments and unfinished follow-ups into the draft.

Design choice

Keep those details between conversations and check the draft before marking it ready for review.

Result

Drafts passed automated checks in 12 of 12 simulated renewal situations, up from 4 of 12.

Trade-off

Keep context between conversations, at the cost of maintaining and updating deal memory.

Show evaluation & design details
  • Evaluates drafts against grounding, preferences, commitments, and follow-up criteria before assigning a release decision.
  • Keeps preferences, open tasks, and prior promises in structured deal memory across turns.
  • Memory compaction reduced stored rows from 45 to 25—approximately 44%—while reported evaluation success rose from 83% to 92%.
  • A separate test caught only 1 of 4 contradictory pricing promises.

Memory lookup and behavioral checks add work before a draft is ready for review.

Renewal Scenario
Agent Memory
Safety Gates
Memory Compaction
Ad Launch Decision Gate

Check the evidence before changing an ad decision.

Uncertain requests get extra review, and changes to protected numeric decisions require supporting evidence.

Design choice

Reserve extra checks for uncertain cases rather than spending the same effort on every request.

Result

A safeguard reduced mistaken ad blocks from 1 to 0 in an 11-case lab test.

Trade-off

Check uncertain requests more deeply, while relying on lighter checks for routine ones.

Show evaluation & design details
  • Uses a fast path for routine inputs and confidence/risk signals to select deeper checks.
  • Requires evidence before revising a protected numeric decision.
  • Generated a decision receipt for all 11 replay cases.
  • Extra checks ran on 27.3% of cases, above the planned 15% limit.
Ad Launch
Runtime Routing
Reasoning Gate
Replay
Full case study
Newsroom AI Quality Gate

Review AI drafts before publication.

Checks for missing information and references, records review decisions, and turns flagged problems into repeatable tests.

Design choice

Keep the AI’s recommendation separate from the decision to release a draft.

Result

Release checks identified all 5 deliberately flawed drafts in a 12-case controlled test.

Trade-off

Hold drafts that fail required checks, even when that adds another review step.

Show evaluation & design details
  • Structured release checks, replayable receipts, and editor-feedback regression tests in a 12-scenario evaluation.
  • Checks required memo fields, policy citation references, and whether support-sensitive claims carry a citation or an explicit Unknown marker.
  • Separates the model's recommendation from the release gate's decision.
  • Records prompt version, policy snapshot, and build fingerprint for review and replay.
  • Converts flagged incidents into regression cases for subsequent versions.
  • A person still needs to judge whether a reference supports the claim.
Editorial Workflow
Release Governance
Regression Tests
Audit Trail
Full case study

Where I Can Help

I connect business needs, technical decisions, and team execution—from defining the problem to testing a solution and planning rollout.

  • Use-case discovery

    Clarify where AI or cloud technology could help—and what is worth testing.

  • AI & cloud solution design

    Shape the architecture and work through cost, performance and risk.

  • Pilot development & evaluation

    Build a focused prototype and test the assumptions that matter.

  • Cross-team delivery leadership

    Bring technical and business teams together around decisions and rollout.

Contact

Contact Information

Got something in mind? Let’s talk.

Tell me what you're trying to achieve, your context, and key constraints.

I usually reply within 1–2 business days.