File cache with diff tracking for AI coding agents. Powered by Turso, a high-performance embedded database.
Agents waste most of their token budget re-reading files they've already seen. cachebro fixes this: on first read it caches the file, on subsequent reads it returns either "unchanged" (one line instead of the whole file) or a compact diff of what changed. Drop-in replacement for file reads that agents adopt on their own.
File cache with diff tracking for AI coding agents. Drop-in MCP server that cuts token usage by 26%.
ดาว
219
เครื่องมือ
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Benchmark
We ran a controlled A/B test: the same refactoring task on a 268-file TypeScript codebase (opencode), same agent (Claude Opus), same prompt. The only difference: cachebro enabled vs disabled.
Without cachebro
With cachebro
Total tokens
158,248
117,188
Tool calls
60
58
Files touched
12
12
26% fewer tokens. Same task, same result. cachebro saved ~33,000 tokens by serving cached reads and compact diffs instead of full file contents.
The savings compound over sequential tasks on the same codebase:
Task
Tokens Used
Tokens Saved by Cache
Cumulative Savings
1. Add session export command
62,190
2,925
2,925
2. Add --since flag to session list
41,167
15,571
18,496
3. Add session stats subcommand
63,169
35,355
53,851
By task 3, cachebro saved 35,355 tokens in a single task — a 36% reduction. Over the 3-task sequence, 53,851 tokens saved out of 166,526 consumed (~24%).
Agents adopt it without being told
We tested whether agents would use cachebro voluntarily. We launched a coding agent with cachebro configured as an MCP server but gave the agent no instructions about it. The agent chose cachebro.read_file over the built-in Read tool on its own. The tool descriptions alone were enough.
The cache persists in a local Turso (SQLite-compatible) database. Content hashing (SHA-256) detects changes. No network, no external services, no configuration beyond a file path.
Installation
npx cachebro init # auto-configures Claude Code, Cursor, OpenCode
That's it. Restart your editor and cachebro is active. Agents discover it automatically.
Or configure manually — add to your MCP config (.claude.json, .cursor/mcp.json, etc.):
Read a file with caching. Returns full content on first read, "unchanged" or diff on subsequent reads. Supports offset/limit for partial reads.
read_files
Batch read multiple files with caching.
cache_status
Show stats: files tracked, tokens saved.
cache_clear
Reset the cache.
Agents discover these tools automatically and prefer them over built-in file reads because the tool descriptions advertise token savings.
As a CLI
cachebro serve # Start the MCP server
cachebro status # Show cache statistics
cachebro help # Show help
Set CACHEBRO_DIR to control where the cache database is stored (default: .cachebro/ in the current directory).
As an SDK
import { createCache } from "cachebro";
const { cache, watcher } = createCache({
dbPath: "./my-cache.db",
sessionId: "my-session-1", // each session tracks reads independently
watchPaths: ["."], // optional: watch for file changes
});
await cache.init();
// First read — returns full content, caches it
const r1 = await cache.readFile("src/auth.ts");
// r1.cached === false
// r1.content === "import { jwt } from ..."
// Second read — file unchanged, returns confirmation
const r2 = await cache.readFile("src/auth.ts");
// r2.cached === true
// r2.content === "[cachebro: unchanged, 245 lines, 1837 tokens saved]"
// r2.linesChanged === 0
// After file is modified — returns diff
const r3 = await cache.readFile("src/auth.ts");
// r3.cached === true
// r3.diff === "--- a/src/auth.ts\n+++ b/src/auth.ts\n@@ -10,3 +10,4 @@..."
// r3.linesChanged === 3
// Partial read — only the lines you need
const r4 = await cache.readFile("src/auth.ts", { offset: 50, limit: 10 });
// Returns lines 50-59, or "[unchanged in lines 50-59]" if nothing changed there
// Stats
const stats = await cache.getStats();
// { filesTracked: 12, tokensSaved: 53851, sessionTokensSaved: 33205 }
// Cleanup
watcher.close();
Architecture
packages/
sdk/ cachebro — the core library
- CacheStore: content-addressed file cache backed by an embedded database
- FileWatcher: fs.watch wrapper for change notification
- computeDiff: line-based unified diff
cli/ cachebro — batteries-included CLI + MCP server
Database: Single Turso database file with file_versions (content-addressed, keyed by path + hash), session_reads (per-session read pointers), and stats/session_stats tables. Multiple sessions and branch switches are handled correctly — each session tracks which version it last saw.
Change detection: On every read, cachebro hashes the current file content and compares it to the cached hash. Same hash = unchanged. Different hash = compute diff, update cache. No polling, no watchers required for correctness — the hash is the source of truth.
Token estimation:ceil(characters * 0.75). Rough but directionally correct for code. Good enough for the "tokens saved" metric.
License
MIT
C
Cachebro
glommer·219 ดาว·
File cache with diff tracking for AI coding agents. Drop-in MCP server that cuts token usage by 26%.