Why Is OpenClaw Slowing Down? Clean Up Old Session Files to Boost Performance

Problem

OpenClaw becomes progressively slower after months of use because each message load incorporates thousands of cron‑generated .jsonl session files into the context. The growing sessions.json file forces the engine to parse unnecessary data on every turn, causing latency to increase with each interaction.

Diagnostic Prompt

Check how many session files are in ~/.openclaw/agents/main/sessions/ and how big sessions.json is. If there are thousands of old cron session files bloating it, delete all the old .jsonl files except the main session, then rebuild sessions.json to only reference sessions that still exist on disk.

Procedure

List the files in ~/.openclaw/agents/main/sessions/ and note the count.

Inspect the size of sessions.json (e.g., du -h sessions.json).

If the count is in the thousands, remove every .jsonl file that is not the primary session file:

find ~/.openclaw/agents/main/sessions/ -name "*.jsonl" ! -name "main_session.jsonl" -delete

Regenerate sessions.json so it only contains references to the remaining files. A typical regeneration command is:

python -m openclaw.tools.rebuild_sessions --dir ~/.openclaw/agents/main/sessions/

Restart OpenClaw and verify that response time returns to normal.

Observed Impact

One user reduced sessions.json from 43 MB to 9.7 MB (≈77 % shrinkage).

Another user dropped the file from 41 MB to 2 MB.

A third case shrank a 142 MB file to 18 MB.

These reductions eliminated the latency spike and restored smooth operation.

Reusable Skill

The prompt was packaged as an OpenClaw “Session Cleaner” skill. The skill can be installed, executed, and will either clean obsolete sessions or report that no action is needed. It can also be scheduled for periodic execution.

GitHub repository containing the skill:

https://github.com/chujianyun/skills/tree/main/skills/openclaw-session-cleaner

Usage Recommendations

Before each heavy conversation batch, inspect the sessions directory for an excessive number of old cron files.

Run the cleanup prompt or invoke the installed skill.

Optionally schedule the skill to run weekly (e.g., via a cron job that calls openclaw run skill openclaw-session-cleaner).

Visual Evidence