claude-webcache
Persistent cross-session WebFetch cache for Claude Code. Cached reads in ~0.07ms — orders of magnitude faster than re-fetching.
Claude Code's built-in cache lasts 15 minutes, within one session. Every new session re-fetches from scratch. claude-webcache persists results across sessions in a local SQLite database — instant cache hits, zero network cost.
Session 1 → WebFetch("docs.example.com") → fetched, auto-cached ✓
Session 2 → cached_fetch("docs.example.com") → instant hit, no network call
Session 7 → cached_fetch("docs.example.com") → still instant, unlimited TTL
v0.1.5+: every WebFetch is automatically saved via PostToolUse hook — nothing to configure.
Install
claude plugin marketplace add theYahia/claude-webcache && claude plugin install claude-webcache@theyahia
Works in: Claude Code CLI · Desktop (Mac/Windows) · VS Code extension · JetBrains plugin — same command everywhere.
Done. Every WebFetch is auto-cached from now on.
Optionally add the usage pattern to ~/.claude/CLAUDE.md to also check the cache before fetching (saves the WebFetch call entirely on repeat URLs).
Plugin TUI not working? There's an open Claude Code bug (#41653) where
/plugin installrejects third-party sources with "source type not supported." Use the CLI command above — it bypasses the TUI and works fine.Fallback (no marketplace):
git clone https://github.com/theYahia/claude-webcache && claude --plugin-dir ./claude-webcache/plugin
Option 2 — npm global
npm i -g @theyahia/claude-webcache
Requires Node.js 22.5+ (uses built-in node:sqlite — no native deps, no install step).
Then register in ~/.claude/settings.json (replace path with output of npm root -g):
{
"mcpServers": {
"claude-webcache": {
"command": "node",
"args": ["/path/from/npm-root-g/claude-webcache/scripts/mcp-server.cjs"]
}
},
"hooks": {
"SessionStart": [
{
"matcher": "startup|clear|compact",
"hooks": [
{ "type": "command", "command": "node /path/from/npm-root-g/claude-webcache/scripts/hook-stats.cjs" }
]
}
]
}
}
Option 3 — clone (contributors)
See CONTRIBUTING.md.
Usage pattern (optional — for pre-fetch cache checks)
v0.1.5+ auto-caches every WebFetch automatically. The pattern below is optional: add it to ~/.claude/CLAUDE.md to also check the cache before making a WebFetch — this saves the WebFetch call entirely on repeat URLs.
Auto-read (v0.5+): nothing to do. A PreToolUse hook checks the cache before every WebFetch/WebSearch. On a hit it serves the cached copy and skips the network; on a miss the call runs normally and the PostToolUse hook stores the result. Same URL + same prompt (or same search query) in any future session = instant hit, zero network cost.
Manual lookup is still available if you want it: call cached_fetch(url, prompt) (or cached_search(query)) — returns the cached text, or [CACHE_MISS] … if absent. Disable auto-read with WEBCACHE_AUTOREAD=0.
⚠ Security — authenticated URLs
The cache stores the URL alongside the response in ~/.webcache/cache.db. By default, claude-webcache strips obvious credentials from the stored URL before write (user:pass@host and query params named token, api_key, apikey, access_token, auth, secret, password, key, signature, etc.).
That's display-level redaction, not key-level. The cache key still hashes the original URL, so re-fetching the same authenticated URL hits the cache. If you want a stricter trade-off:
export WEBCACHE_STRICT_REDACT=1
With WEBCACHE_STRICT_REDACT=1, the cache key is computed from the redacted URL too — endpoints differing only in ?token=A vs ?token=B collide in one slot. Safe for pass-through auth (identical content), unsafe for personalized endpoints (different users see each other's cached data).
Bottom line: prefer header-based auth (Authorization: headers) over URL-embedded tokens. Don't commit ~/.webcache/cache.db to git.
Namespaces
Multiple projects sharing one machine? Isolate per-project caches:
WEBCACHE_NAMESPACE=gosdelo claude # cache writes/reads scoped to ns "gosdelo"
WEBCACHE_NAMESPACE=qsearch claude # separate ns, no cross-contamination
Default namespace is the empty string "" (shared cache for v0.3 behavior). Inspect/manage per-namespace via CLI: claude-webcache namespaces, claude-webcache --namespace gosdelo stats.
Tools (MCP)
CLI
The npm package ships a claude-webcache binary for ad-hoc inspection and a local web dashboard:
claude-webcache stats # JSON stats
claude-webcache stats --by-domain # per-domain breakdown
claude-webcache list 20 # 20 most-recent URLs
claude-webcache list 50 --offset 100 # pagination
claude-webcache invalidate https://news.com/123 # drop one URL
claude-webcache refresh https://news.com/123 --prompt "extract title" # invalidate one (url,prompt) pair
claude-webcache warm urls.txt --prompt "extract" # bulk pre-flight check
claude-webcache clear --older-than-days 30 # partial wipe
claude-webcache clear --confirm YES # full wipe (requires explicit confirm)
claude-webcache clear-logs # truncate ~/.webcache/hook.log
claude-webcache namespaces # list all namespaces present
claude-webcache export --out cache.json --all # export metadata
claude-webcache dashboard # open http://localhost:37778
claude-webcache --namespace gosdelo stats # scope command to namespace
The dashboard renders top URLs by hits, top domains (with avg hits / last fetch / entry counts), full search-able paginated list with one-click invalidate + refresh buttons. Pure stdlib — no extra deps to install.
Configuration (env vars)
SessionStart hook
Every new session injects a one-liner so Claude knows the cache exists:
webcache [ns=gosdelo] 142 pages cached, 87% hit rate, last fetch 3h ago
No output if cache is empty. [ns=...] is omitted when using the default namespace.
Storage
SQLite at ~/.webcache/cache.db (WAL mode, synchronous=NORMAL, busy_timeout=5000).
Cache key = SHA256(namespace + "|" + canonical(url) + "|" + prompt). Default TTL: unlimited (set WEBCACHE_TTL_DAYS=N for N-day expiry).
URL canonicalization (v0.4+): lowercase hostname, strip default ports (:80/:443), strip fragment, sort query parameters alphabetically. So https://EXAMPLE.com/p?b=2&a=1#frag and https://example.com/p?a=1&b=2 produce the same cache key — no silent miss on URL formatting variance.
Concurrent-safe via WAL + 5-second busy_timeout — multiple Claude Code sessions can read/write simultaneously without SQLITE_BUSY errors.
Limits
- Cache key includes the prompt — use consistent prompts to maximize hit rate.
- Output is whatever WebFetch returns (already summarized). No re-processing.
- No semantic search. Exact
(namespace, canonical_url, prompt)match only.
Benchmarks
Single-process latency on a populated DB (N=10000 entries, 1KB output each), measured via npm run bench:
Storage overhead: ~2 KB per entry for a 1 KB payload (key + indexes + WAL + new v0.4 columns). With WEBCACHE_COMPRESS=1 on text-heavy responses, expect 3-7× reduction.
WebFetch over the network typically takes 1-5 seconds — a cached hit is ~15,000-70,000× faster. Reproduce on your hardware: npm run bench. See bench/README.md for methodology and full results metadata (CPU, RAM, OS, commit) saved per run.
Related
- claude-mem — persistent memory across sessions (complements claude-webcache: memory vs. web cache)
- WWmcp — catalog of 46 MCP servers for non-Western APIs
License
MIT — see LICENSE.