Use Clash with Cursor IDE in 2026: Split Rules for Extensions and Model API Requests

Why Cursor Deserves a Toolchain-Specific Routing Lane

In 2026, Cursor IDE is not just another Electron wrapper around a text buffer. It continuously talks to API endpoints for inline models and agents, pulls binaries and extension payloads from CDN and marketplace infrastructure, and occasionally overlaps with the broader VS Code ecosystem when you install community extensions. That traffic pattern is meaningfully different from opening ChatGPT in a browser tab, even though both experiences feel like “AI.”

When developers report that “the internet works but Cursor does not,” the failure is often policy-shaped: a broad GEOIP rule sends one Cursor hostname down DIRECT while another rides a congested default PROXY, or DNS bypasses Clash so DOMAIN rules never see the names you think you wrote. A developer proxy setup that treats Cursor as a first-class citizen—rather than as a footnote inside a generic foreign-traffic bucket—makes those mismatches visible and fixable.

This article complements, rather than replaces, product-specific split guides. If you are optimizing OpenAI and Anthropic endpoints in isolation, read the ChatGPT and Claude split-rules walkthrough first; it focuses on vendor APIs for standalone assistants. Here the emphasis is the Cursor editor as a workflow surface: how to group extension marketplace and update downloads separately from streaming model calls, how policy-based splitting interacts with long-lived HTTP/2 streams, and how to validate each hop without turning your entire profile into global tunnel mode.

Symptoms That Scream “Split Cursor, Not Just the Browser”

Classic clues include: web search and Git load normally; Cursor settings “Network” diagnostics partially fail; extension search spins then times out; chat or Tab completions freeze mid-stream; updates download at a trickle while other HTTPS sites saturate your line. These patterns usually mean multiple host families are involved, not a single blocked IP.

Because Cursor reuses VS Code’s extension model, some installs still reach marketplace.visualstudio.com or open-vsx.org depending on configuration and mirrors. Your Clash log might show a successful rule hit for *.cursor.sh while a parallel request to a Microsoft or Open VSX hostname still walks a domestic-direct path that cannot complete within the client timeout. Treat marketplace traffic as its own troubleshooting thread alongside first-party Cursor domains.

Another common trap is assuming the desktop app honors the system HTTP proxy the same way a browser does. Many Electron apps prefer direct TLS stacks or bundled networking; until you enable transparent capture, flows can miss the policy path you tested in Chrome. When in doubt, plan toward TUN after your domain rules behave under controlled tests, using the TUN mode guide for stack-specific notes.

Hostname Inventory: First-Party Cursor Surfaces

Cursor publishes allowlist-oriented guidance for enterprise firewalls. Treat the following as a starting inventory you verify in your own connection log after one successful session, not as a frozen law of physics. Product teams add regions, shards, and helper hosts over time.

According to Cursor’s public security and network documentation, core API traffic uses hosts under *.cursor.sh, including shards such as api2.cursor.sh for many API calls, api3.cursor.sh and regional gcpp.cursor.sh variants for Tab-style features, api5.cursor.sh for agent workloads, and repo42.cursor.sh for codebase indexing. Authentication flows may touch authenticate.cursor.sh and authenticator.cursor.sh. Static delivery and marketplace-related fetches often involve *.cursor-cdn.com, *.cursorapi.com (including marketplace.cursorapi.com), downloads.cursor.com, and in some paths Amazon S3 buckets such as anysphere-binaries.s3.us-east-1.amazonaws.com for binaries.

When translating that inventory into Clash, prefer DOMAIN-SUFFIX,cursor.sh and DOMAIN-SUFFIX,cursor-cdn.com over endless per-host DOMAIN lines unless you have a reason to pin. Keep DOMAIN-KEYWORD usage rare; broad keywords create accidental matches and painful debugging sessions months later.

Structuring Proxy-Groups: Extensions, AI, or One “CURSOR” Lane

Two sensible patterns exist. The minimal approach defines one select or url-test group—call it CURSOR—and routes every first-party suffix there. The finer approach splits CURSOR_AI for streaming API shards from CURSOR_PKG for marketplace and CDN downloads so you can assign a low-latency node to chat while letting large binaries use a different path that tolerates throughput shaping.

Either way, names in rules must reference real proxy-groups entries. Beginners often paste provider snippets that reference 🚀 节点选择-style labels from another profile; if your local YAML never defined that label, Clash will not magically infer intent. Mirror membership between CURSOR and your general PROXY group until you have evidence that split nodes help.

Latency tests matter for AI lanes more than people expect. Streaming completions keep connections open; a marginal node looks like “the model stopped thinking” instead of a crisp HTTP error. Configure url-test with sober intervals and realistic probe URLs—avoid hyper-aggressive failover that flaps whenever a single probe blips. For foundational explanations of group types and ordering, revisit the rule-based routing deep dive before you tune timers.

A Practical Rule Block (Conceptual YAML)

The excerpt below is illustrative. Insert it above broad GEOIP or regional direct rules so first-match semantics do not accidentally park Cursor traffic on the wrong outbound. Adjust outbound names to match your profile.

# Conceptual excerpt — verify suffixes against your logs and vendor docs
proxy-groups:
  - name: CURSOR_AI
    type: select
    proxies:
      - NODE-A
      - NODE-B
      - DIRECT
  - name: CURSOR_PKG
    type: select
    proxies:
      - NODE-B
      - NODE-A
      - DIRECT

rules:
  - DOMAIN-SUFFIX,cursor.sh,CURSOR_AI
  - DOMAIN-SUFFIX,cursorapi.com,CURSOR_PKG
  - DOMAIN-SUFFIX,cursor-cdn.com,CURSOR_PKG
  - DOMAIN-SUFFIX,cursor.com,CURSOR_PKG
  - DOMAIN-SUFFIX,downloads.cursor.com,CURSOR_PKG
  - DOMAIN-SUFFIX,s3.us-east-1.amazonaws.com,CURSOR_PKG
  # Optional VS Code ecosystem mirrors — confirm in your log before enabling
  # - DOMAIN-SUFFIX,open-vsx.org,CURSOR_PKG
  # - DOMAIN-SUFFIX,marketplace.visualstudio.com,CURSOR_PKG
  # ... GEOIP / MATCH follow ...

If you collapse to a single group, point both suffix blocks at CURSOR instead. The important discipline is explicit ordering: Cursor-specific lines should appear before catch-all domestic or foreign shortcuts that might mis-classify shared CDN IPs.

Rule Order and Shared Infrastructure Gotchas

GEOIP before Cursor exceptions is the classic footgun. Country databases are useful and imperfect; anycast edges mean the IP your resolver returns might not match your mental map of where Anysphere infrastructure terminates. If a wide GEOIP,XX,DIRECT line wins first, you can waste hours swapping nodes when the real fix was moving a few DOMAIN-SUFFIX lines above it.

Amazon S3 style rules deserve caution. DOMAIN-SUFFIX,s3.us-east-1.amazonaws.com matches more than Cursor; if you park that line on an expensive node without thought, unrelated tooling that hits the same region might follow. A tighter fix is logging the exact bucket hostname your failing download used, then switching to DOMAIN for that bucket if the log supports it.

Duplicate contradictory rules sneak in when merging community providers with personal overrides. After every merge, scan for repeated suffixes with different outbounds. First match wins, but humans lose when two sources disagree silently.

DNS, Fake-IP, and HTTP/2 Streaming

Clash does not read application intent from thin air. Resolver mode, fake-ip, and operating-system secure DNS all change which names the rule engine observes. The symptom is familiar: TLS looks correct in a packet capture, yet your log shows a flow matched against an IP-only rule you never meant to write.

Under fake-ip, Clash synthesizes short-lived answers so it can recover the true domain when connections arrive—keeping DOMAIN rules honest. That breaks when another resolver bypasses Clash, which happens with browser DoH, some VPN stacks, or Android Private DNS pointed at a public provider while your profile assumes hijack. Align OS resolver settings, Clash DNS listeners, and TUN capture so queries and connections share one policy world.

Cursor’s own documentation highlights another layer: many AI features rely on HTTP/2 bidirectional streaming. Corporate gateways that downgrade, buffer, or inspect TLS sometimes turn streaming into apparent hangs. Vendor guidance suggests HTTP/1.1 compatibility modes when you sit behind strict proxies; in Clash terms, that is a reminder that the problem may sit upstream of your YAML even when rules are perfect. Still fix routing first—split rules remove an entire class of false negatives where half the app used a working path and half did not.

Verification: Small Experiments Beat Random Toggles

Cursor ships network diagnostics inside settings; run them after each policy change. Externally, vendor docs propose simple TLS and streaming probes against representative API hosts—use them to distinguish TLS inspection issues from plain routing failures. When logs grow noisy, filter by cursor substrings rather than scrolling endlessly.

After deploying rules, execute a three-step checklist: trigger a short chat completion, open the extension marketplace and search for a common plugin, and check for pending app updates. For each step, confirm which rule hit in the Clash log. If the hit conflicts with your intent, adjust ordering or DNS before you chase exotic node protocols.

Document the working stack when you find it: core version, GUI build, DNS mode, group names, and any TUN toggle. Future you—and teammates importing your snippet—will otherwise repeat the same scavenger hunt after the next automatic update.

What “Stable” Means for a Developer Desktop

Stability is layered: healthy upstream nodes, sane MATCH defaults, DNS consistency, laptop sleep settings, and the vendor’s own rate limits. Clash governs the middle. No rule compensates for an expired subscription, a datacenter outage, or an account flagged by automated abuse detection.

Compared with ad hoc per-browser extensions, keeping Cursor IDE routes inside a maintained Mihomo-family profile means your editor policy evolves beside the rest of your networking—exactly where it belongs if AI-assisted coding is part of daily work rather than an occasional web experiment.

Iterate With Logs, Not Lore

Community paste bins love outdated hostname lists. Prefer vendor documentation for first-party patterns, your own logs for VS Code marketplace mirrors, and incremental edits. When something breaks after an app update, assume a new shard or CDN prefix before you assume your nodes died.

For neutral reference material beyond these opinionated defaults, pair this walkthrough with the configuration documentation hub on this site.

Closing Thoughts

Clash remains most valuable when you treat it as a structured policy engine, not a single on-off tunnel. In 2026, giving Cursor IDE explicit lanes for model API traffic versus marketplace and CDN fetches mirrors how developers actually debug: isolate the failing surface, confirm the rule hit, then tune DNS and streaming behavior. Alongside single-product AI guides, this page is the toolchain-oriented companion—focused on the editor shell rather than on one model vendor alone.

Compared with brittle browser-only workarounds, a clean split profile keeps extension downloads and model streams on paths you can measure, switch, and explain to teammates who share the same rough network conditions.

→ Download Clash for free and experience the difference.