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lizheng220/README.md

Hi, I'm Brent 👋

AI agent engineering + backend. Both sides of my work come down to the same question: how do you get a system to finish the job when nobody is watching — instead of quietly getting it wrong?

On the agent side that means permission boundaries, context management, and acceptance criteria that can actually be falsified. On the backend side it means idempotency, refuse-to-write guardrails, and data consistency. The failure mode is identical either way: silent degradation costs far more than a crash.


🤖 AI Agent Engineering

Pushing agents from "can call a tool" to "can deliver a whole work item on their own."

Permission boundaries belong in the tool layer, not in the prompt. A multi-role pipeline — researcher → critic → executor → verifier — where each role gets its own tool allowlist. The critic and the verifier physically cannot write files; overreach isn't forbidden by a rule the model may ignore, it's unavailable.

Acceptance criteria have to be falsifiable. "Make it run" is not a criterion. "Write a failing test that reproduces it, then make it green" is. When every step carries its own verify, an agent can run a task end to end without a human pressing Enter at each turn.

Predict first, then verify. Write down the expected result before running anything, and accept on the diff. Treating a green light as proof is the most expensive illusion there is — green means nothing crashed, not that anything was done correctly.

What I'm digging into: agent runtime reliability. What happens when a compaction trigger and its size estimator disagree on the ruler; where tool-result truncation boundaries fall; how a run recovers and resumes after failure. Currently doing source-level investigation on agent frameworks including vercel/eve and espressif/esp-claw.

Claude Code · Agent SDK · MCP · multi-agent orchestration · skills / hooks · LLM application engineering


⚙️ Backend

Order and logistics pipelines for cross-border e-commerce — keeping data consistent as it moves between ERP, Shopify, Feishu Bitable, and internal platforms.

The most valuable code I've written isn't features. It's guardrails.

  • Idempotency and refuse-to-write guards come before automation. One read timeout should never cost a full day of shipping records.
  • Silent degradation costs more than a crash. Falling back to 0 when a hardcoded column index misses is far more dangerous than raising — nobody ever finds out.
  • Performance work changes the shape of the data, not the size of the machine. A representative result: an internal dashboard's first paint went 26.5s → 137× less data transferred, with the hot endpoint 600× faster — all from query and serialization changes.

Underneath all of that sits a set of services running against live business every day: order sync, pre-shipment stock checks, approval-flow exports, and 50+ other modules.

Python · PostgreSQL · FastAPI · Docker Compose · Playwright · Feishu Open Platform · Shopify / ERP integrations


🌱 Open Source

Project What Status
deepseek-ai/deepseek-harness #5573 Root-caused 36 of 48 Windows test failures to one cause — suites creating symlinks without the privilege Windows requires — and measured the fix: EPERM failures 36 → 0, with 21 of those tests now running on Windows rather than skipped Reported · maintainer-engaged
deepseek-harness fs-sandbox Reproduced a containment gap where ino === 0 collapses filesystem identity and admits paths outside the sandbox; verified the fail-closed guard, corrected the filesystem premise it was reported under, and flagged that the 64-bit file ID is documented as non-unique on ReFS Verified patch · 100% branch coverage
microsoft/skill-recorder #72 Dependency-free i18n foundation + Simplified Chinese Open · CLA signed
selfhosted-tracker-eval Isolated evaluation sandbox for Cattr / ActivityWatch: loopback-only ports, dedicated networks and volumes, resource caps Public

DeepSeek Harness takes no external pull requests, so that work lands as reproductions, measurements and reviewable patches attached to the thread rather than as commits.

Where I contribute: agent runtime reliability — context management, tool-call boundaries, sandbox containment, failure recovery. The method is the same every time: reproduce it in isolation, measure before and after, and state which claims are measured and which are only documented.


📌 About

  • 📍 Hangzhou, China
  • 🛠 Python as the primary language; TypeScript when the work calls for it
  • 📮 GitHub issues and PRs are the fastest way to reach me

A conclusion worth putting in code is one a test could have proven wrong.

Pinned Loading

  1. selfhosted-tracker-eval selfhosted-tracker-eval Public

    并行试用 Cattr 与 ActivityWatch 的隔离评测沙箱:loopback-only 端口、独立网络与卷、资源上限,一条命令拆干净。

  2. deepseek-ai/deepseek-harness deepseek-ai/deepseek-harness Public

    DeepSeek Harness: Everything is a Plugin.

    TypeScript 274k 33.5k

  3. microsoft/skill-recorder microsoft/skill-recorder Public

    Desktop app that records your on-screen work session and uses the GitHub Copilot SDK to reconstruct it as an intent + ordered steps, then builds a reusable Skill or Automation for Microsoft Autopil…

    TypeScript 5.7k 648