precc-token-saver

# PRECC Token Saver PRECC (Predictive Error Correction) intercepts every shell command before it runs. In under 3ms it: - **Fixes wrong-directory errors** — detects the correct project root and prepends `cd /correct/path &&` - **Compresses CLI output** — rewrites commands through RTK (60–90% smaller output) - **Applies learned skills** — uses patterns mined from past sessions to prevent repeated failures - **Translates git→jj** — auto-converts git commands in Jujutsu repos (saves ~40 tokens per `git add`) **Measured results** (29 real sessions, 5,384 bash calls): - 34% cost saving ($296 saved from $878 baseline) - 98% of failures prevented (352/358) - 2.93ms average hook latency ## How it works in OpenClaw > **Note:** OpenClaw does not yet have a native `PreToolUse` hook (unlike Claude > Code). This skill works via **prompt-level instruction**: the SKILL.md is loaded > into the agent's context and the agent is instructed to manually pipe every shell > command through `precc-hook` before executing it. Interception is LLM-enforced, > not OS-level. A native hook equivalent is tracked in > [openclaw/openclaw#7597](https://github.com/openclaw/openclaw/issues/7597). When PRECC Token Saver is active, the agent follows this pattern for every shell command it wants to run: 1. Construct the JSON payload for `precc-hook` 2. Pipe it through `precc-hook` on stdin 3. Read the (possibly rewritten) command from stdout 4. Execute the rewritten command instead of the original ``` Agent wants to run: cargo build ↓ precc-hook receives: {"tool_input": {"command": "cargo build"}} precc-hook outputs: {"hookSpecificOutput": {"updatedInput": {"command": "cd /path/to/project && rtk cargo build"}}} ↓ Agent executes: cd /path/to/project && rtk cargo build ``` ## Setup ```bash # Install PRECC curl -fsSL https://raw.githubusercontent.com/yijunyu/precc-cc/main/scripts/install.sh | bash # Initialise (one-time) precc init # Mine existing session history (optional) precc ingest --all ``` ## Commands Once the skill is loaded, you can address the agent directly: - `@precc report` — show token savings and command statistics - `@precc skills list` — list active correction skills - `@precc update` — update PRECC binaries to the latest release - `@precc savings` — show dollar-value savings estimate ## Skill behaviour This skill is loaded as a system-level instruction into the agent's context. The agent (not the platform) is responsible for enforcing the hook pattern. The agent is instructed to: 1. **Always** route shell/bash tool calls through `precc-hook` by constructing the hook JSON payload and parsing the response before execution. 2. **On session start**, run `precc init` if the databases are absent. 3. **On session end**, optionally run `precc report` and summarise savings. 4. **Never** skip the hook even for simple commands — the latency is <3ms and the hook is fail-open (any error → original command is used unchanged). ## Hook invocation pattern ```bash # Wrap any command through precc-hook: echo '{"tool_input":{"command":"YOUR_COMMAND_HERE"}}' | precc-hook ``` Parse the JSON response: - If `.hookSpecificOutput.updatedInput.command` is non-empty → use it - Otherwise → use the original command unchanged ## Advanced: savings report ```bash precc report # full analytics dashboard precc savings # dollar-value breakdown precc skills list # active skills precc skills show <name> # detail for one skill ``` ## License MIT — https://github.com/yijunyu/precc-cc