Settings → Developer → Edit Config, merge this into mcpServers, then fully quit and reopen Claude Desktop.
We couldn’t confirm it starts correctly
We ran the install command but it didn't respond within our test window — this can mean a slow first-time install rather than a real problem.
uvx llmtrim
Process exited before answering initialize.
This is an experimental automated check and can have false negatives — missing environment variables, a slow cold install, etc. It doesn’t necessarily mean something’s wrong. Last checked 10d ago.
You run Claude Code, Codex, Cursor, or your own app. Every turn, the tool sends a large request: system prompt, tools, history, raw command output. You pay for every token of that, including the parts that do not help the model.
A 200-line build log with two errors. Tool schemas resent on every call. JSON with hundreds of near-identical rows. That bulk is still billed.
llmtrim sits on your machine as a local proxy, trims the waste, and forwards a smaller request. The reply is unchanged. You keep the same tools and answers; you spend less.
Code
before: your tool ───── full request ─────▶ OpenAI / Anthropic / …
◀──────── reply ──────────
after: your tool ──▶ llmtrim ──smaller──▶ OpenAI / Anthropic / …
(on your machine)
◀──────── reply ────────── (same answer)
Compression cannot raise your bill or break a request; worst case is zero savings. Everything runs locally, nothing is sent to us. In action →
For Claude Code the same install also wires /sub to route sessions through another subscription. Details →
Get started
Terminal
npm install -g @llmtrim/cli@latest && llmtrim setup
# open a new terminal, then keep working
llmtrim status
That's it. setup starts a local proxy and wires your shell. When Claude Code is present, it also turns on /sub. You do not run a separate install for that.
You want
Run
First install
llmtrim setup
New version
llmtrim update (then llmtrim ensure after npm/brew/cargo)
Something broken
llmtrim ensure · llmtrim doctor --fix · or f in status
Any tool that honors HTTPS_PROXY works (Claude Code, Codex, Cursor, Aider, your SDK). GitHub Copilot does not (certificate pinning). Full list →
Other installers (Homebrew, curl, Scoop, Cargo, Docker)
Menu-bar / system-tray popover with the same savings numbers. Bundled in Homebrew, Scoop, and npm; setup can enable open-at-login. Open with llmtrim tray. On Linux desktops, interactive ensure can fetch the tray binary from the latest release (needs libwebkit2gtk-4.1 and libayatana-appindicator3).
Is this safe?
Same technique as mitmproxy, scoped to LLM API hosts only. setup changes three things; llmtrim uninstall reverses all three:
Private CA in ~/.llmtrim/ (name-constrained; cannot intercept your bank or email)
Shell env: HTTPS_PROXY + CA trust
Login service: daemon at login
No API keys stored (your tool's auth is forwarded). Prompts never touch disk; only anonymous token counts. Recoverable tool results stay in bounded daemon RAM for five hours by default and disappear on restart. Full threat model: SECURITY.md.
llmtrim status # savings + health (aliases: monitor, gain)
llmtrim update # new release, restart daemon, refresh integrations
llmtrim ensure # match the recommended install state on this machine
Situation
Command
Watch savings
llmtrim status
After npm / brew / cargo upgrade
llmtrim ensure (or f in status)
Diagnose
llmtrim doctor · repair with doctor --fix
Pause / resume proxy
llmtrim stop · llmtrim start
Force one session through llmtrim
llmtrim wrap claude
Remove everything
llmtrim uninstall
After setup, update, or ensure, owned Claude Code /sub stays in sync with the binary.
Time series: llmtrim status --daily · --weekly · --monthly · --json · --csv.
In action
An agent ran a build. The tool returned 58 lines; two were errors. All 58 would have been billed.
4,662 chars → 978 (−79%). Errors stay verbatim. Repeated INFO lines fold into a template plus the values (lossless when the range is regular).
text
# before (noise + signal)
[2026-06-13T10:02:00Z] INFO compiling module core::worker::task_0 (incremental)
… 28 more near-identical INFO lines …
[2026-06-13T10:02:31Z] ERROR src/worker/pool.rs:214: mismatched types: expected `usize`, found `i64`
… 25 more INFO lines …
[2026-06-13T10:03:01Z] ERROR src/net/conn.rs:88: cannot borrow `buf` as mutable more than once
[2026-06-13T10:03:02Z] INFO build failed, 2 errors
# after (errors verbatim; INFO folded losslessly)
[{}] INFO compiling module core::worker::task_{} (incremental) [×30: (10:02:00Z..10:02:29Z step 1s; 0..29)]
[2026-06-13T10:02:31Z] ERROR src/worker/pool.rs:214: mismatched types: expected `usize`, found `i64`
[{}] INFO compiling module core::net::conn_{} (incremental) [×25: 10:02:32Z..10:02:56Z; 0..24]
[2026-06-13T10:03:01Z] ERROR src/net/conn.rs:88: cannot borrow `buf` as mutable more than once
[2026-06-13T10:03:02Z] INFO build failed, 2 errors
Log folding is one stage. Others kick in on different waste:
Waste
What happens
Build logs, diffs, grep dumps
Keep errors / changes / matches; fold the rest
Long pasted context
Keep chunks relevant to the question
Source code
Keep useful bodies; rest → signatures
Tool schemas every turn
Trim + keep the cache prefix stable
Huge JSON arrays
Compact table (TOON) or sample
Verbose model replies
Ask for terser output where safe
[!IMPORTANT]
Compression cannot raise your bill or break a request. Each stage is re-measured with the provider's real tokenizer and undone if it does not save tokens. If the provider rejects the compressed body, the original is resent. Worst case is zero savings.
Existing prompt-cache prefixes (cache_control) are left alone. First-arrival recoverable shaping (llmtrim recall r_…) is off by default; live-zone tool-output windowing still runs, and a re-run of the same tool ships in full. To skip shaping for a command (verbatim stdout, including a terminal trailer), set toolout_passthrough = ["*gpt.sh*"] or prefix the command with LLMTRIM_TOOL_OUTPUT=passthrough. Lines starting with LLMTRIM_KEEP: survive windowing even when the rest is clipped.
All 10 compressors
Stages run in savings order. Nothing under a cache_control marker is rewritten.
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Frequently Asked Questions about Llmtrim
llmtrim is an MCP server that compresses LLM prompts, tool output, and replies to reduce token usage and cost. It also operates as a local proxy for LLM API traffic, keeping processing on your machine. It is available alongside CLI and library interfaces, and is designed to preserve the same answers and tools.
Install llmtrim with npm and run its setup command: `npm install -g @llmtrim/cli@latest && llmtrim setup`. The setup starts a local proxy and wires your shell; you can check the installation with `llmtrim status`.
llmtrim compresses LLM prompts, tool output, and replies, including content such as conversation requests, tool schemas, command output, and repetitive JSON. It forwards a smaller request to the LLM API to reduce token usage and cost.
It compresses traffic locally before forwarding the smaller request to the configured LLM service.
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