Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add jasonkneen/lazar --skill log-rotationgit clone --depth 1 https://github.com/jasonkneen/lazarWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/jasonkneen/lazar/log-rotation)<a href="https://agentmods.dev/skills/jasonkneen/lazar/log-rotation"><img src="https://agentmods.dev/badge/skills/jasonkneen/lazar/log-rotation/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/jasonkneen/lazar/log-rotation"><img src="https://agentmods.dev/badge/skills/jasonkneen/lazar/log-rotation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00000 | $0.00964 |
| Opus 5 | $0.00000 | $0.00482 |
| Sonnet 5 | $0.00000 | $0.00193 |
| Haiku 4.5 | $0.00000 | $0.00096 |
Grade A, and why
log-rotation scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 81 lines — stays where its author put it; the contents beside it link to each section on GitHub.
log-rotation
Add a richer memory summary for a rotated Lazar stream archive.
The kernel auto-rotates stream.jsonl when it exceeds LAZAR_LOG_MAX_BYTES (default 10MB). That is the safety floor. The kernel owns logs/: sandboxed tools and hooks may read logs, but must not write, compress, prune, or repair them.
The kernel writes a minimal summary into memory/log-summaries/<ts>.md whenever it rotates. This skill is the polish layer on top: read one archive with bounded commands and append useful human navigation details to memory.
When to use
- After kernel auto-rotation, if you want richer summaries than the minimal kernel header.
- When a
memory/log-summaries/<ts>.mdfile exists but needs top prompts, top commands, or a small file-touch index. - The user explicitly asks "summarize the last session" or similar.
Do NOT run this on every prompt. Once per archive is plenty.
Hard rules
logs/is trusted kernel-owned state. Do notmv,gzip,rm, truncate, or write anything under$LAZAR_HOME/logsfrom a sandboxed skill or hook.- Rotation itself is kernel-owned and non-destructive at the moment it happens: the live log moves to
.bak, and the next append creates a freshstream.jsonl. - Full-fidelity archive retention is kernel policy, controlled by
LAZAR_LOG_ARCHIVE_KEEP. Summaries inmemory/log-summaries/are the durable navigation layer. - Write enriched summaries only under
$LAZAR_MEMORY, usuallymemory/log-summaries/ormemory/distilled/. - Always bound archive reads. Never
cata whole archive.
Recipes
Check current stream size
LOG=$LAZAR_HOME/logs/stream.jsonl
[ -f "$LOG" ] && wc -c "$LOG"
Pick the newest rotated archive
ARCHIVE=$(ls -t $LAZAR_HOME/logs/stream.jsonl.*.bak 2>/dev/null | head -n 1)
[ -n "$ARCHIVE" ] || { echo "no raw archive found"; exit 0; }
If an archive has already been pruned by the kernel, use the matching memory/log-summaries/<ts>.md summary as the durable record.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 10d ago First seen · 81 lines · 0 tokens per session scan A 617751ac2ca9
log-rotation is a skill published in the GitHub repository jasonkneen/lazar (31 stars, last pushed 29d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 964 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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