China Mirror Resolver

Mirror URLs break frequently. This skill teaches the agent a self-healing workflow: discover → validate → configure the best available source. A baseline table provides offline fallback; web search enables self-repair.

Execution Flow

User error / request
      │
      ▼
 1. Identify tool type (Section 1)
      │
      ▼
 2. Detect current source config
      │
      ▼
 3. Try ALL baseline sources for that tool (Section 2)
    Validate each with Section 4 thresholds (< 3s = good, 3–10s = acceptable)
      ├─ At least one source < 10s → pick fastest → go to step 6
      └─ All sources > 10s or failed ↓
      ▼
 4. [IF search capable] Search for latest sources (Section 3)
      ├─ Found candidates → go to step 5
      └─ No candidates found → report to user with baseline table as reference
    [IF no search] Report baseline failure to user, suggest manual URL
      │
      ▼
 5. Validate ALL candidates (Section 4), pick fastest passing one
      ├─ At least one passes → go to step 6
      └─ All fail → report failure to user, suggest checking network/proxy
      │
      ▼
 6. Backup original config → write new config → verify with test command
      │
      ▼
 7. Confirm result to user (show old source → new source, response time)

Graceful degradation: If the agent has no web search capability, skip step 4 and use only the baseline table. The skill remains functional with reduced self-healing ability.

Speed selection: When multiple sources pass validation, always select the one with the lowest response time. Test all candidates, not just the first.

1. Diagnostic Table

Match error keywords to identify the tool, then check current config:

Error keywords	Tool	Detect current source
`pip` / `PyPI` / `setup.py` / `No matching distribution`	pip	`pip config get global.index-url`
`npm ERR` / `FETCH_ERROR`	npm	`npm config get registry`
`yarn` / `ESOCKETTIMEDOUT`	yarn	`yarn config get registry` (v1) / `yarn config get npmRegistryServer` (v2+)
`pnpm` / `ERR_PNPM`	pnpm	`pnpm config get registry`
`conda` / `CondaHTTPError` / `PackagesNotFoundError`	conda	`conda config --show channels`
`docker` / `pull` / `manifest` / `toomanyrequests`	Docker	Linux/macOS: `docker info \| grep -A5 "Registry Mirrors"` / Win: Docker Desktop → Settings → Docker Engine
`go: downloading` / `GOPROXY` / `dial tcp`	Go	`go env GOPROXY`
`cargo` / `crates.io` / `Blocking waiting`	Rust (cargo)	check `~/.cargo/config.toml` (Linux/macOS) or `%USERPROFILE%\.cargo\config.toml` (Win)
`rustup` / `could not download`	Rust (rustup)	`echo $RUSTUP_DIST_SERVER` / `$env:RUSTUP_DIST_SERVER`
`maven` / `pom.xml` / `BUILD FAILURE` / `Could not resolve`	Maven	check `~/.m2/settings.xml` or `C:\Users\<user>\.m2\settings.xml`
`gradle` / `Could not resolve` / `build.gradle`	Gradle	check `build.gradle` / `build.gradle.kts` or `~/.gradle/init.gradle`
`brew` / `Homebrew` / `Fetching`	Homebrew	`echo $HOMEBREW_BOTTLE_DOMAIN`
`apt` / `dpkg` / `E: Failed to fetch`	apt (Debian/Ubuntu)	check `/etc/apt/sources.list`
`yum` / `dnf` / `Cannot find a valid baseurl`	yum/dnf (CentOS/RHEL/Fedora)	check `/etc/yum.repos.d/`
`git clone` / `github.com` / `RPC failed`	GitHub accelerator	N/A
`huggingface` / `hf_hub` / `ConnectionError`	Hugging Face	`echo $HF_ENDPOINT` / `$env:HF_ENDPOINT`

2. Baseline Sources

High-stability institutional mirrors. Try these first. If all fail or are too slow (> 10s), proceed to Section 3 (search). Agents without search capability stop here.

pip

Provider	URL
Tsinghua TUNA	`https://pypi.tuna.tsinghua.edu.cn/simple`
Aliyun	`https://mirrors.aliyun.com/pypi/simple/`
USTC	`https://pypi.mirrors.ustc.edu.cn/simple/`
Tencent	`https://mirrors.cloud.tencent.com/pypi/simple/`

npm / yarn / pnpm

Provider	URL
npmmirror	`https://registry.npmmirror.com`
Huawei	`https://repo.huaweicloud.com/repository/npm/`

conda

Provider	URL
Tsinghua TUNA	`https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main`
USTC	`https://mirrors.ustc.edu.cn/anaconda/pkgs/main`
Aliyun	`https://mirrors.aliyun.com/anaconda/pkgs/main`

Docker

Provider	URL
1ms.run	`https://docker.1ms.run`
xuanyuan.me	`https://docker.xuanyuan.me`
DaoCloud	`https://docker.m.daocloud.io`
linkedbus	`https://docker.linkedbus.com`

Go

Provider	URL
goproxy.cn	`https://goproxy.cn`
goproxy.io	`https://goproxy.io`

Rust

Provider	cargo registry	rustup server
USTC	`sparse+https://mirrors.ustc.edu.cn/crates.io-index/`	`https://mirrors.ustc.edu.cn/rustup`
Tsinghua TUNA	`sparse+https://mirrors.tuna.tsinghua.edu.cn/crates.io-index/`	`https://mirrors.tuna.tsinghua.edu.cn/rustup`
RsProxy.cn	`sparse+https://rsproxy.cn/crates.io-index/`	`https://rsproxy.cn/rustup`

Maven / Gradle

Provider	URL
Aliyun Public	`https://maven.aliyun.com/repository/public`
Aliyun Google	`https://maven.aliyun.com/repository/google`
Huawei	`https://repo.huaweicloud.com/repository/maven`

Homebrew (macOS / Linuxbrew)

Provider	HOMEBREW_BOTTLE_DOMAIN
Tsinghua TUNA	`https://mirrors.tuna.tsinghua.edu.cn/homebrew-bottles`
USTC	`https://mirrors.ustc.edu.cn/homebrew-bottles`

apt (Debian / Ubuntu)

Provider	Base URL
Tsinghua TUNA	`https://mirrors.tuna.tsinghua.edu.cn`
Aliyun	`https://mirrors.aliyun.com`
USTC	`https://mirrors.ustc.edu.cn`

yum / dnf (CentOS / RHEL / Fedora)

Provider	Base URL
Tsinghua TUNA	`https://mirrors.tuna.tsinghua.edu.cn`
Aliyun	`https://mirrors.aliyun.com`
USTC	`https://mirrors.ustc.edu.cn`

GitHub Accelerator

Provider	Prefix URL
ghfast.top	`https://ghfast.top/`
gh-proxy.com	`https://gh-proxy.com/`
ghp.ci	`https://ghp.ci/`

Hugging Face

Provider	HF_ENDPOINT
hf-mirror.com	`https://hf-mirror.com`

3. Search Strategy

Capability gate: This section requires web search. If the agent lacks search capability, skip to Section 5 using only baseline sources.

3.1 Search Query Templates

Replace <YEAR> with current year. Use the agent's available search mechanism. Provide both Chinese and English queries for better coverage:

Tool	Chinese query	English query
pip	`pip 国内镜像源 <YEAR> 可用`	`pip china mirror source <YEAR> working`
npm	`npm 国内镜像 registry <YEAR>`	`npm china registry mirror <YEAR>`
conda	`conda 国内镜像源 channels <YEAR>`	`conda china mirror channel <YEAR>`
Docker	`docker 镜像加速源 <YEAR> 可用`	`docker registry mirror china <YEAR> working`
Go	`GOPROXY 国内代理 <YEAR>`	`GOPROXY china proxy <YEAR>`
Rust	`cargo crates 国内镜像 <YEAR>`	`cargo crates china mirror <YEAR>`
Maven	`maven 国内镜像仓库地址 <YEAR>`	`maven china mirror repository <YEAR>`
Homebrew	`homebrew 国内镜像 <YEAR>`	`homebrew china mirror <YEAR>`
apt	`ubuntu apt 国内源 <YEAR>`	`ubuntu apt china mirror <YEAR>`
yum/dnf	`centos yum 国内镜像源 <YEAR>`	`centos yum china mirror <YEAR>`
GitHub	`github 加速代理镜像站 <YEAR>`	`github proxy accelerator china <YEAR>`
HuggingFace	`huggingface 国内镜像下载加速 <YEAR>`	`huggingface china mirror download <YEAR>`

3.2 Source Credibility

Prioritize results in this order:

Official mirror site docs (mirrors.tuna.tsinghua.edu.cn/help, developer.aliyun.com/mirror)
Mirror provider's own site/README (goproxy.cn, npmmirror.com)
Recent posts (< 3 months) from reputable tech communities
GitHub repos with > 100 stars that aggregate mirror lists

Reject: undated articles, posts > 6 months old, zero-reply forum threads, unverifiable personal blogs.

3.3 Candidate Extraction Rules

Extracted URLs must:

Use HTTPS protocol
Belong to known institutions (.edu.cn, major cloud vendors, well-known OSS orgs) OR be cross-referenced in 2+ independent articles
Come from articles published within the last 6 months

Security warning: Never use mirror sources from unknown individuals or unverifiable personal servers. Malicious mirrors can inject tampered packages. Especially for Docker and pip, only use sources from recognized institutions.

4. Validation

Every candidate must pass validation before being written to config.

4.1 Universal HTTP Check

# Linux / macOS
start=$(date +%s%N 2>/dev/null || perl -MTime::HiRes=time -e 'printf "%d\n",time()*1e9')
code=$(curl -o /dev/null -s -w "%{http_code}" --max-time 10 "<URL>")
end=$(date +%s%N 2>/dev/null || perl -MTime::HiRes=time -e 'printf "%d\n",time()*1e9')
echo "HTTP $code | $(( (end - start) / 1000000 ))ms"

# Windows PowerShell
$sw = [System.Diagnostics.Stopwatch]::StartNew()
try { $r = Invoke-WebRequest -Uri "<URL>" -TimeoutSec 10 -UseBasicParsing -ErrorAction Stop
  $sw.Stop(); "OK: HTTP $($r.StatusCode) | $($sw.ElapsedMilliseconds)ms"
} catch { $sw.Stop(); "FAIL: $_" }

4.2 Tool-Specific Validation

Tool	Command / Check	Success Criteria
pip	`pip install --dry-run requests -i <URL> --trusted-host <HOST>`	`Would install` or `already satisfied`
npm	`npm view lodash version --registry <URL>`	Returns version number
yarn v1	`yarn info lodash version --registry <URL>`	Returns version number
pnpm	`pnpm view lodash version --registry <URL>`	Returns version number
conda	`conda search numpy -c <URL> --override-channels`	Returns package list
Docker	HTTP GET `<URL>/v2/`	HTTP 401 (auth required = service alive)
Go	HTTP GET `<URL>/github.com/gin-gonic/gin/@v/list`	Returns version list
Rust	HTTP GET the sparse index URL	HTTP 200
Maven	HTTP GET `<URL>/org/apache/commons/commons-lang3/maven-metadata.xml`	Returns XML content
HuggingFace	HTTP GET `<URL>/api/models?limit=1`	Returns JSON

4.3 Acceptance Criteria

Response Time	Rating	Action
< 3000ms	Excellent	Use this source
3000–10000ms	Acceptable	Use if no faster alternative found
> 10000ms or timeout	Unusable	Try next candidate

Selection rule: Test ALL available candidates (baseline + search-discovered), then select the one with the lowest response time that passes validation.

4.4 Batch Validation Scripts

Pre-built scripts in scripts/:

scripts/validate.sh — Linux / macOS (bash). Supports --json flag for machine-readable output.
scripts/validate.ps1 — Windows (PowerShell)

bash scripts/validate.sh              # test all, colored output
bash scripts/validate.sh pip           # test pip only
bash scripts/validate.sh all --json    # machine-readable JSON output

4.5 Security Notes on Validation

trusted-host warning: Using --trusted-host with pip disables SSL certificate verification for that host. This is a security trade-off. Only use it when the mirror is a known institution (e.g., .edu.cn, major cloud vendor) and the connection is within a trusted network. Prefer mirrors that have valid SSL certificates and do not require trusted-host.

5. Configuration

Core Principles

Backup first — Always backup the original config file before modifying
Merge, don't overwrite — For JSON configs (Docker daemon.json), read existing content and merge new fields. Never blindly overwrite the entire file
Permanent config — Write to config files, not just CLI flags
Verify after write — Run a test command to confirm the new source works

Detailed configuration templates for each tool are in references/config-templates.md. Below is a quick reference of the key commands.

Quick Reference

pip: pip config set global.index-url <URL>

npm: npm config set registry <URL>

yarn v1: yarn config set registry <URL>

yarn v2+: yarn config set npmRegistryServer <URL>

pnpm: pnpm config set registry <URL>

conda: conda config --add channels <URL> && conda config --set show_channel_urls yes

Docker: Read existing daemon.json, add/update registry-mirrors array, write back, restart Docker. See references/config-templates.md for merge logic.

Go: go env -w GOPROXY=<URL>,direct && go env -w GOSUMDB=sum.golang.google.cn

Rust (cargo): Write [source.crates-io] + [source.mirror] to ~/.cargo/config.toml

Rust (rustup): Set RUSTUP_DIST_SERVER and RUSTUP_UPDATE_ROOT env vars

Maven: Add <mirror> block to ~/.m2/settings.xml

Gradle (Groovy): Add maven { url '<URL>' } to repositories block

Gradle (Kotlin): Add maven(url = "<URL>") to repositories block

Homebrew: Set HOMEBREW_BREW_GIT_REMOTE, HOMEBREW_CORE_GIT_REMOTE, HOMEBREW_BOTTLE_DOMAIN env vars

apt: Replace archive.ubuntu.com with mirror host in /etc/apt/sources.list, then sudo apt update

yum/dnf: Backup /etc/yum.repos.d/, replace baseurl in repo files, then sudo yum makecache

GitHub: Prepend accelerator prefix: git clone <PREFIX>https://github.com/<owner>/<repo>.git

HuggingFace: Set HF_ENDPOINT=<URL> env var

6. Restore Official Sources

Tool	Restore Command
pip	`pip config unset global.index-url`
npm	`npm config set registry https://registry.npmjs.org`
yarn v1	`yarn config set registry https://registry.yarnpkg.com`
yarn v2+	`yarn config set npmRegistryServer https://registry.yarnpkg.com`
pnpm	`pnpm config set registry https://registry.npmjs.org`
conda	`conda config --remove-key channels`
Go	`go env -w GOPROXY=https://proxy.golang.org,direct`
Docker	Remove `registry-mirrors` from daemon.json (keep other fields), restart
Rust (cargo)	Remove `[source.*]` sections from config.toml
Rust (rustup)	`unset RUSTUP_DIST_SERVER RUSTUP_UPDATE_ROOT`
Maven	Remove `<mirror>` block from settings.xml
Homebrew	`unset HOMEBREW_BREW_GIT_REMOTE HOMEBREW_CORE_GIT_REMOTE HOMEBREW_BOTTLE_DOMAIN`
apt	Restore `/etc/apt/sources.list` from backup, `sudo apt update`
yum/dnf	Restore `/etc/yum.repos.d/` from backup, `sudo yum makecache`
HuggingFace	`unset HF_ENDPOINT`

7. Notes

Docker & GitHub accelerators have the highest churn rate — always validate before configuring
If the user has an enterprise Nexus/Artifactory, prefer that over public mirrors
WSL 1 and WSL 2 have different network stacks; WSL 2 has its own IP and needs separate Docker/apt config
If HTTP_PROXY / HTTPS_PROXY env vars are set, some tools may bypass mirrors and go through the proxy instead
On ARM architectures (Apple Silicon, ARM Linux), verify that the mirror hosts packages for your architecture
When multiple Python/Node versions coexist (pyenv, nvm, conda envs), config may need to target specific environments rather than global settings
Use scripts/validate.sh or scripts/validate.ps1 for periodic health checks

8. Known Unstable Sources

This section is informational. Always validate before use rather than relying solely on this list, which may itself become outdated.

Source	Status (2026-03)	Notes
`pypi.douban.com` (pip)	Dead	Connection reset
`ghproxy.cc` (GitHub)	Dead	SSL certificate untrusted
`mirrors.aliyun.com/goproxy/` (Go)	Unstable	Homepage 404, module downloads intermittent

9. Cross-Agent Adaptation

Capability Requirements

Capability	Required?	Used in	If absent
Terminal/shell	Required	Steps 2, 4, 5, 6	Cannot function
File read/write	Required	Steps 5, 6	Cannot write config
Web search	Optional	Step 4	Use baseline table only (Section 2)
Web fetch	Optional	Step 4	Use `curl` / `Invoke-WebRequest` via terminal

Platform Adaptation

Claude Code / StepFun: Native support. Place folder in ~/.claude/skills/ or ~/.stepfun/skills/.

Cursor: Create .cursor/rules/china-mirror-resolver.mdc with this content:

---
description: Resolve slow package downloads in China by switching to domestic mirrors. Triggers on: timeout, mirror, 换源, 镜像源, 下载慢
globs:
alwaysApply: false
---

[Paste the content of this SKILL.md here, excluding the YAML frontmatter]

Windsurf: Create .windsurf/rules/china-mirror-resolver.md with this content:

---
trigger: auto
---

[Paste the content of this SKILL.md here, excluding the YAML frontmatter]

Generic LLM (no skill system): Include Section 2 (baseline table) and Section 5 (config quick reference) in the system prompt. Skip Section 3 (search) if the LLM has no search tool.

China Mirror Resolver

China Mirror Resolver

Execution Flow

1. Diagnostic Table

2. Baseline Sources

pip

npm / yarn / pnpm

conda

Docker

Go

Rust

Maven / Gradle

Homebrew (macOS / Linuxbrew)

apt (Debian / Ubuntu)

yum / dnf (CentOS / RHEL / Fedora)

GitHub Accelerator

Hugging Face

3. Search Strategy

3.1 Search Query Templates

3.2 Source Credibility

3.3 Candidate Extraction Rules

4. Validation

4.1 Universal HTTP Check

4.2 Tool-Specific Validation

4.3 Acceptance Criteria

4.4 Batch Validation Scripts

4.5 Security Notes on Validation

5. Configuration

Core Principles

Quick Reference

6. Restore Official Sources

7. Notes

8. Known Unstable Sources

9. Cross-Agent Adaptation

Capability Requirements

Platform Adaptation

Download

Skill Info