@prom.codes/saver

prom.codes Saver — cut token cost without cutting quality. A tiny, pure-JS MCP installer (stdio): one setup tool writes an efficient-output rule block into your agent's runtime configs so it spends fewer tokens on its own prose — preamble, play-by-play narration, pasted tool output — while keeping code, caveats and destructive sequences verbatim.

It is the third prom.codes tool, alongside prom.codes Context (code retrieval) and prom.codes Memory (agent memory).

Quick start (Claude Code)

claude mcp add saver -- npx -y @prom.codes/saver@latest

No key needed. claude mcp add defaults to local scope; add --scope project for a committable .mcp.json. Other hosts (Cursor, VS Code) use the same command/args in their own config.

Then ask your agent to run setup once per workspace. Levels: lite (filler only), balanced (default — lean, not terse), aggressive (telegraphic, opt-in, never for code/destructive work). The rules keep code, caveats, destructive steps and anything the agent needs later verbatim — it shapes phrasing, never what the agent does or remembers.

It installs itself. An MCP server can't act on its own, so the rule only saves tokens once it's in a config file. On startup the Saver auto-installs the marked rule block into config files you already have (CLAUDE.md / AGENTS.md / Cursor / Augment) — idempotent, never creates a new file, skipped for home/root, opt out with PROMETHEUS_SAVER_AUTO_SETUP=off. Run setup to install into all runtimes (incl. creating AGENTS.md if you have none). A status tool reports where it writes, the key state, which runtimes already have the block, and whether a newer version is published.

No database and no native modules — npx works turnkey everywhere (Node ≥ 20.10). The workspace is auto-detected (Claude Code CLAUDE_PROJECT_DIR); set PROMETHEUS_WORKSPACE_ROOT only to target a different folder. An API key is optional: the Saver works fully without one, and accepts the same PROMETHEUS_API_KEY (prom_live_<tag>_<secret>) as prom.codes Context and Memory to tie the install to your account.

Docs: https://prom.codes/docs/mcp/saver