In early 2026, agentic workflows built on Claude Opus 4.7 and Claude Code moved from demos to daily engineering. The failure mode is rarely “Anthropic is down.” It is mixed traffic: claude.ai loads in a browser while the Anthropic API stalls on TLS, npm install crawls through the wrong egress, and long-running agent sessions hit idle proxy timeouts that look like model slowness. This guide treats Clash Verge Rev as the policy layer that separates Anthropic API calls, registry downloads, and GitHub-shaped toolchain traffic so each path picks the right node, resolver behavior, and timeout story.

Nothing here replaces reading official Anthropic documentation for API keys, workspace limits, or Claude Code permissions. Think of this article as the networking appendix your README seldom spells out: how to keep api.anthropic.com deterministic, how to stop Node and Claude Code from inheriting half-configured shells, and how to debug “works in the browser, dies in the terminal” without rebooting on hope. If you still need subscription import, TUN setup, or baseline Windows guidance, continue with the full Clash Verge Rev Windows setup tutorial after you finish the routing concepts below.

Anthropic and npm publish many hostname families across regions and CDNs. Treat the domain lists below as templates you extend after you observe real DNS lookups in your own traces. Copy-pasting mega rule blocks without verification is how MATCH policies quietly send API traffic through the wrong proxy group.

Why Claude Code and Anthropic API traffic stress proxies differently

Agentic development amplifies concurrency. A human chats slowly in a browser; Claude Code may stream tool results, call the Anthropic API repeatedly, pull packages from registry.npmjs.org, and clone or fetch assets from GitHub in parallel. Each hop respects different libraries: Chromium honors OS proxy settings when configured, Node might read HTTPS_PROXY only after you export it, and some runtimes cache environment variables at spawn time so later edits never apply until you restart the IDE.

Clash Verge Rev wraps the Mihomo core with a GUI that makes policy iteration tolerable. The practical trick is not “turn everything on.” Classify flows into predictable buckets: interactive claude.ai browsing, streaming API traffic to api.anthropic.com, npm and package mirrors, GitHub API and raw hosts, and local loopback services that must stay DIRECT. Once buckets exist, assign each to a proxy group whose latency profile matches the workload—often a stable research-oriented node for API streams versus a domestic-friendly hop for large registry downloads—without forcing unrelated traffic through one overloaded tunnel.

Misconfigured proxy routing masquerades as API timeouts. Claude Opus 4.7 responses wait on chunked streams, Claude Code retries tool calls, or npm stalls mid-download when an HTTP proxy enforces short idle limits. Stable routing narrows those failures to credentials, rate limits, or genuine upstream defects rather than invisible packet detours.

How this differs from Cursor-only or AWS-centric setups

Teams comparing Claude Code vs Cursor often assume one proxy recipe covers every IDE. Cursor may bundle its own update channels and model gateways; Claude Code leans on Anthropic’s API surface and your local shell environment. If you already followed our AWS Agent Toolkit routing guide, reuse the same discipline—explicit domain rules, layered verification, and careful TUN versus system-proxy choice—but swap AWS hostname families for Anthropic and JavaScript toolchain hosts.

The 2026 wave of agentic AI rewards boring networking. When Claude Opus 4.7 evaluations depend on hour-long sessions, jitter and handshake retries compound into “the model got dumber” narratives. Fixing routing first keeps comparisons fair.

Bucket your traffic before editing YAML

Open a notes file and answer four questions without touching configuration yet. Which browsers or apps must reach claude.ai or anthropic.com interactively? Which terminals run Claude Code or SDK scripts that ignore Windows or macOS proxy toggles? Which npm registries and GitHub hosts does your project touch during install and CI? Which local services bind to loopback and must never traverse a remote proxy?

Capture representative URLs from live logs rather than imagination. For Anthropic API work you routinely see api.anthropic.com, occasionally telemetry or CDN siblings depending on product surface, and console or account pages on claude.ai. For JavaScript tooling, registry.npmjs.org dominates, but corporate mirrors or regional caches deserve their own matchers. GitHub traffic splits across github.com, api.github.com, and raw.githubusercontent.com—each can appear in install scripts independently.

Claude Code introduces another axis. Some operations spawn subprocesses that inherit your shell; others launch from GUI shortcuts that never saw export HTTPS_PROXY. Document launch paths the way you document API keys so teammates stop guessing why “it works in iTerm but not in VS Code.”

Choose system proxy versus TUN with a decision checklist

Start with system proxy when every critical binary respects OS-level settings and your subscription routing already satisfies Anthropic endpoints through rulesets. Clash Verge Rev exposes mixed-port or dedicated HTTP/SOCKS listeners; pointing Windows or macOS at those listeners keeps the blast radius smaller than installing tunnel drivers. Many developer laptops prefer this path when corporate MDM policies scrutinize kernel extensions.

Switch to TUN mode when Claude Code, npm, or language servers bypass OS proxy entirely yet still need policy routing. Build pipelines, containerized sandboxes, and certain Node HTTP stacks fall into this bucket. TUN elevates visibility: packets hit the virtual adapter and inherit Clash decisions even when individual libraries forgot proxies existed. The tradeoff is operational friction—firewall prompts, coexistence with other VPN clients, and mandatory attention to DNS redirection choices on Windows with Wintun.

Stable evaluations pair one dominant capture mode with explicit exceptions. Running system proxy and TUN concurrently without a mental map is how engineers chase ghosts for hours.

Document your choice in the team wiki. Future-you needs to know whether curl traces should include --proxy overrides or whether packet captures should appear on the TUN adapter. That discipline pays dividends when someone joins mid-project and inherits half your shell aliases.

DNS alignment is part of Anthropic API reliability

API endpoints interact tightly with DNS correctness. When Clash operates in fake-ip mode, domain rules resolve quickly inside the stack but can confuse external observers who expect real addresses in every diagnostic. When you prefer redir-host semantics, upstream resolvers shoulder more load but mirror traditional expectations for packet captures.

Regardless of mode, avoid stale caches after rapid rule edits. Flush OS resolver caches when browsers stubbornly reach old regions, and align bootstrap DNS inside Clash with servers your ISP or office permits. Split-stack environments—corporate split-tunnel VPN plus Clash—amplify DNS leaks when each layer believes it owns search domains.

Never tunnel sensitive Claude or Anthropic sessions through unknown third-party TLS interception proxies. If your subscription injects middleboxes, verify trust chains explicitly before typing credentials or pasting API keys into terminals.

Step 1 — Promote Anthropic and toolchain hosts ahead of coarse MATCH rules

Modern Mihomo-compatible profiles favor rule providers and rulesets, yet the sequencing principle stays timeless: explicit wins over vague. Insert domain rules for API and registry hosts before continent-sized GEOIP matches or generic proxy groups. Below is an illustrative fragment—adapt names such as PROXY or AI-WORK to match your profile’s actual policy groups. 

# Illustrative fragments — replace policy groups with yours
DOMAIN-SUFFIX,api.anthropic.com,AI-WORK
DOMAIN-SUFFIX,anthropic.com,AI-WORK
DOMAIN-SUFFIX,claude.ai,AI-WORK
DOMAIN-SUFFIX,registry.npmjs.org,NPM-WORK
DOMAIN-SUFFIX,github.com,DEV-WORK
DOMAIN-SUFFIX,api.github.com,DEV-WORK

Splitting AI-WORK from NPM-WORK matters when streaming API traffic tolerates different latency than bursty tarball downloads. Some teams route Anthropic streams through a low-jitter node while letting npm ride cheaper transit. Others unify paths for simplicity. Either approach succeeds when the YAML reflects your operational reality instead of cargo-cult defaults copied from forum snippets.

Monitor Clash logs while running a short Claude Code task. New hostnames appear when products ship incremental CDN or telemetry endpoints. When an unfamiliar name surfaces, add it deliberately rather than widening MATCH wildcards until everything leaks through one overloaded node.

Step 2 — Wire Node, npm, and Claude Code with consistent proxy variables

Anthropic’s HTTP APIs and npm both honor proxy environment variables when configured consistently—but only if every launcher exports them. Standardize on one canonical shell profile and avoid duplicating snippets across five IDE-specific wrappers.

On Windows, distinguish user-wide environment variables from session-scoped ones created inside integrated terminals. On macOS, GUI apps launched from the Dock might ignore terminal exports unless you launch editors from the same shell that sourced proxies. These nuances explain bug reports where curl https://api.anthropic.com works in one window but Claude Code fails in another despite identical YAML.

Step 3 — Keep loopback and local agents on DIRECT policies

Local language servers, test harnesses, and mock APIs typically bind to loopback. Ensure Clash routes 127.0.0.1 and ::1 through DIRECT unless you deliberately tunnel loopback—almost nobody should. Complement YAML with thorough NO_PROXY coverage so Claude Code plugins that call local services do not traverse a remote HTTP proxy by accident.

If you run containerized agents, remember Docker and Podman introduce separate network namespaces. You may need per-container proxy variables or host-gateway routing instead of assuming host TUN policies apply inside containers automatically.

Step 4 — Verify with layered evidence instead of single-tab optimism

Browser checks alone lie politely. Combine three observations: a session on claude.ai, a CLI probe against https://api.anthropic.com (respecting Anthropic’s terms—use documented health or lightweight authorized calls rather than hammering production), and an npm metadata fetch such as npm ping or installing a tiny package in a throwaway directory. When only one layer fails, you narrow rapidly to proxy inheritance rather than wholesale outages.

  1. Open a fresh terminal after enabling Clash listeners and confirm ports match Verge settings.
  2. Run a trivial HTTPS probe against a host your rules already classify (for example your registry or a documented Anthropic endpoint you are allowed to test).
  3. Launch Claude Code from that verified shell so inheritance chains stay visible.
  4. Capture verbose logs only after baseline routing proves sane—verbosity hides fundamentals when policy is wrong.

Keep timestamps aligned. Laptop sleep, captive portals, and DHCP renewals coincide with rule pushes more often than teams admit. A simple sequential notebook entry beats mythology when debugging Claude Opus 4.7 latency complaints.

Troubleshooting Anthropic API and Claude Code timeout combinations

claude.ai works while Claude Code reports connection errors

Likely causes include missing api.anthropic.com rules, Claude Code launched without inherited proxy variables, or HTTP/2 streaming blocked by an aggressive middlebox on one egress only. Confirm which terminal or IDE spawn path Claude Code uses, re-export variables, and compare Clash logs during a failing request versus a successful browser session.

Anthropic API succeeds while npm install stalls

Registry traffic may fall into a different proxy group with higher latency or stricter body-size limits. Add explicit rules for registry.npmjs.org and any mirror you configured. Check whether npm honors HTTPS_PROXY while also holding stale npm config proxy entries that conflict.

Streaming responses truncate mid-generation

Some HTTP proxies enforce idle timeouts shorter than long model streams. Try a node group tuned for long-lived connections, disable redundant double-proxy chains, and ensure you are not stacking corporate VPN HTTP inspection on top of Clash without understanding both idle timers.

401 or 403 errors after fixing routing

Once connectivity stabilizes, authentication issues surface clearly. Verify ANTHROPIC_API_KEY scope, workspace membership, and model access for Opus-tier models. Routing fixes do not grant permissions your key never had.

Everything worked until corporate VPN connected

Split-tunnel VPNs reorder interface metrics and DNS search lists. Reevaluate whether Clash should bind DNS exclusively or cooperate with VPN-provided resolvers. Sometimes the fix is intentional simplicity—route Anthropic-bound flows inside VPN policy rather than stacking conflicting redirects.

Operational habits for dependable Claude Code sessions

Snapshot working YAML before benchmark weeks. Tag profiles inside Clash Verge Rev so engineers rotate between “daily driver” and “Claude Code evaluation” without midnight edits. Rotate API keys after screen shares—agents and terminals log aggressively—and monitor usage dashboards so rate-limit errors do not masquerade as network faults.

Encourage teammates to publish sanitized hostname suffix lists when they add rule entries. Privacy matters, yet communal logs accelerate debugging without exposing tenant identifiers. Coupling social discipline with technical routing yields boringly reliable sessions—the best kind when comparing Claude Code against other agentic stacks in 2026.

Frequently asked questions

Why does Claude Code time out while the Claude web app works?

Different stacks honor proxies differently. Confirm Claude Code reads the same environment variables as your shell, verify api.anthropic.com resolves to the region you expect, and inspect whether idle timeouts differ between HTTP proxies and long-lived streams.

Which Anthropic API hostname should I route explicitly?

Start with api.anthropic.com plus anthropic.com and claude.ai surfaces your traces show. Extend with CDN or telemetry hosts only after logs justify them. Avoid MATCH-first profiles that hide surprises until incidents.

Should I enable TUN mode on Windows for Claude Code?

Use TUN when binaries ignore OS proxy settings yet still need unified routing. Skip TUN when MDM forbids adapters or when system proxy already covers every toolchain you measured.

How do I keep npm installs stable alongside Anthropic API traffic?

Route registry hosts explicitly, align environment variables and optional npm proxy config deliberately, and keep local registries inside NO_PROXY.

Does proxy routing replace Anthropic API key security?

Never. Routing polish complements key hygiene and workspace permissions but does not shrink blast radius on compromised credentials.

Agentic development on Claude Opus 4.7 deserves transparent networking. Treat each hostname family as data, align Clash Verge Rev policies with measured traces, and wire Claude Code with the same rigor you apply to production deploy scripts. Reliability becomes boring—which means your evaluation finally focuses on software quality instead of invisible packet detours.