AI tool comparison
Ferretlog vs Kelet
Which one should you ship with? Here is the side-by-side panel verdict, pricing read, reviewer split, and community vote comparison.
Developer Tools
Ferretlog
git log for your Claude Code agent runs — local, zero dependencies
50%
Panel ship
—
Community
Free
Entry
Ferretlog is a zero-dependency pure Python CLI that treats your Claude Code session logs like a git repository. It parses the raw JSONL logs in `~/.claude/projects/` and gives you git-style history browsing, diff between runs, per-tool-call breakdowns, and cost/token stats — entirely locally, with no network calls and no configuration required. If you've been using Claude Code heavily, you've likely experienced the frustration of losing track of what changed across sessions, what tools were called how many times, and how much each session actually cost across sub-agent calls. Ferretlog makes that history explorable and comparable the same way `git log` makes code history explorable. This is an indie solo project from Eitan Lebras, submitted as a Show HN. It's genuinely useful as a power-user tool for anyone doing serious Claude Code work, especially those managing multi-session agent pipelines where debugging "what did the agent do last time?" is a real pain. The zero-dependency, local-only design means there's no trust surface and no setup friction.
Developer Tools
Kelet
Reads your LLM traces, finds failure patterns, and hands you the prompt fix
75%
Panel ship
—
Community
Free
Entry
Kelet is a root-cause analysis agent for LLM applications that goes beyond trace visualization. Where most observability tools stop at showing you what happened, Kelet automatically reads your traces, cross-references failure patterns across thousands of sessions — thumbs-down ratings, abandoned conversations, LLM-judge flags — generates root cause hypotheses, and produces targeted prompt patches to address them. The workflow is: connect your traces (LangSmith, Langfuse, or direct API), let Kelet ingest your failure signals, and receive a prioritized list of failure clusters with explanations and draft prompt fixes. SOC 2 Type II certified, read-only access to traces — nothing is mutated. The indie team positions it as the missing "closing of the loop" in LLM observability: most teams can detect failures but have no systematic path from detection to fix. The HN thread surfaced a real pain point: teams know their chatbot is failing somewhere, but diagnosing which prompts, tools, or routing decisions are responsible requires manual trace archaeology. Kelet automates that archaeology and produces actionable output, not just dashboards.
Reviewer scorecard
“If you run Claude Code daily, you need this immediately. Being able to diff two sessions like git commits and see exactly which tools fired and what they cost is something that should have existed from day one. Zero-dependency Python means it just works.”
“The loop has been open for too long — collect traces, stare at them, guess at fixes, repeat. Kelet closes it. Read-only access is the right trust model for early adoption. If it actually surfaces actionable prompt patches instead of generic insights, this becomes a staple of any serious LLM app development workflow.”
“This is a niche tool for a niche user (heavy Claude Code power users) and the session log format Anthropic uses is undocumented and could change at any update. Tying workflows to internal log parsing is fragile infrastructure — treat it as a convenience, not a dependency.”
“Automated prompt patches from an LLM analyzing other LLM failures is a confidence game — how do you know the fix didn't introduce a new failure mode? Without a rigorous eval harness baked into the loop, you're swapping one unknown for another. The SOC 2 cert is good but the methodology needs more transparency.”
“Agent observability tooling built by the community, not the vendor, is how this ecosystem will mature. Ferretlog is primitive but it points at a real gap: we need git-style versioning and auditability for agent sessions, not just for code.”
“LLM apps are entering the maintenance and reliability phase — the 'build it and see' era is over. Systematic failure analysis with auto-generated remediation is the natural next layer of the stack. Kelet is early, but the category is real and it will be important infrastructure within 18 months.”
“Terminal-only, Claude Code-specific, no visuals — this tool exists entirely outside my workflow. The underlying insight (session replay and cost tracking) is useful, but it needs a UI before it reaches anyone outside the developer community.”
“If you've shipped a chatbot or AI writing tool and are drowning in 'the bot said something weird' support tickets, Kelet is the triage system you didn't know you needed. Finding which prompt variant is responsible for the weirdness has historically been a manual nightmare.”
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