CEO % Co-founder @cometml, creators of Opik

New York, USA
Joined April 2009
LLMs and RAGs are powerful, but without a strong evaluation pipeline, you're flying blind. Here's how to systematically test and improve your GenAI Apps. 🧵 (1/6)
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You should operate under the assumption that all of your private data will become public in the next 2 years. Not even Google/iCloud is safe long term.
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If models already stumble onto system exploits as a side effect of benchmark optimization, what happens when persistence is the explicit objective function? What actually stops someone from using RL to reward root access, weight cloning, and anti-shutdown behavior directly?
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Gideon M retweeted
Everyone’s racing to build agent-first UX, but what does that really look like? Our Product Design Lead goes behind the scenes on her research, decisions, and challenges she faced optimizing Opik for users and agents working in the terminal instead of the application UI: comet.com/site/blog/agent-fi…
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Honestly pretty torn on open weight models after the OpenAI/Hugging Face situation. On one hand, letting people fine tune away safety guardrails is a real risk. On the other, overly strict guardrails just tie the hands of security people when things go wrong.
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Opik cost intelligence does all of this for you and more.
How to keep AI spend flat while token usage grows exponentially: Not with friction and spend alerts. With better defaults, routing, and caching. Better Defaults (not Usage Caps) – Engineers can choose any model they want, but defaults matter. We’re experimenting with defaulting to open weight models like GLM 5.2 and Kimi 2.7 through our LLM gateway, while still encouraging engineers to choose the right model for the task. 91% of our employees were never hitting their usage caps, so instead of lowering caps and driving up alerts, we're moving to cheaper defaults. Note that code reviews use a diversity of models, so they can check each other's work. Better Routing – In our custom harnesses, we preprocess prompts and route to the best model for the job, considering cache hits and model pricing. For instance, you may want a frontier model for planning, but not for execution where they can be overkill. Ultimately, humans shouldn't be choosing models - AI can automate this task. Better Caching – Cache misses are the easiest way to drive your cost up. All of our requests are cache aware, so we’re reusing a warm cache wherever possible. For example, our cache hit rate went from 5% → 60% in LibreChat once properly implemented. Keep Context Lean – Start fresh sessions when switching tasks. Scope file context narrowly. Disconnect unused tools. Don't just compact. The goal isn't fewer tokens used, it's fewer tokens wasted. Better Visibility – Our engineers can use as many tokens as they want, from whatever model they want, but we’ve made usage visible – and the more you spend on AI, the more impact we expect. The goal isn't to suppress usage. It's to build the infrastructure that makes exponential growth sustainable. Putting this into practice has cut our AI spend nearly in half, while our token usage continues to grow.
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How to keep AI spend flat while token usage grows exponentially: Not with friction and spend alerts. With better defaults, routing, and caching. Better Defaults (not Usage Caps) – Engineers can choose any model they want, but defaults matter. We’re experimenting with defaulting to open weight models like GLM 5.2 and Kimi 2.7 through our LLM gateway, while still encouraging engineers to choose the right model for the task. 91% of our employees were never hitting their usage caps, so instead of lowering caps and driving up alerts, we're moving to cheaper defaults. Note that code reviews use a diversity of models, so they can check each other's work. Better Routing – In our custom harnesses, we preprocess prompts and route to the best model for the job, considering cache hits and model pricing. For instance, you may want a frontier model for planning, but not for execution where they can be overkill. Ultimately, humans shouldn't be choosing models - AI can automate this task. Better Caching – Cache misses are the easiest way to drive your cost up. All of our requests are cache aware, so we’re reusing a warm cache wherever possible. For example, our cache hit rate went from 5% → 60% in LibreChat once properly implemented. Keep Context Lean – Start fresh sessions when switching tasks. Scope file context narrowly. Disconnect unused tools. Don't just compact. The goal isn't fewer tokens used, it's fewer tokens wasted. Better Visibility – Our engineers can use as many tokens as they want, from whatever model they want, but we’ve made usage visible – and the more you spend on AI, the more impact we expect. The goal isn't to suppress usage. It's to build the infrastructure that makes exponential growth sustainable. Putting this into practice has cut our AI spend nearly in half, while our token usage continues to grow.
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It’s pretty amazing to see how much the Claude Code/Codex default settings are designed to just burn tokens. There are dozens of configuration changes you can make that will drop token consumption with zero impact on quality. Each one is about 1%-3% in cost savings, but together you can easily get to 30%. On top of that, you've got a bunch of defaults that can potentially impact quality but might be totally irrelevant in your case.
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Gideon M retweeted
We're having Gideon Mendels (@gidim ) over on June 18 for a panel talk. The man behind Opik by @Cometml: the fastest-growing open-source project for agent observability, testing, and optimisation. Catch his insights: luma.com/agentsummit
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A customer showed me their coding agent bill and asked us to help figure out where it was all going. Turns out ~30% was misconfiguration. Bloated context, unused skills, broken MCPs. That's why we built Cost Intelligence on Opik, launching today. It plugs into Claude Code and Codex, finds the waste, and fixes org-wide settings with one click
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over-engineered a "smart" analog gauge for my espresso machine ☕️ Custom PCB, Seeed XIAO MC, and a non-linear scale for 92–97°C precision. The enclosure is SLM metal 3D printed and hand-sanded to match the chrome. Fully open-source: github.com/gidim/e61-gauge
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One of our users after starting to use Ollie: "This shit will make you want to stay up till 3 am shipping agents with diet coke and Parliaments" 😂
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As your agent matures, something shifts. You stop writing code, and start editing prompts, tweaking params, trying new tools, etc. The tooling for this phase sucks. Today, we’re fixing that. Announcing Agent Configuration + Agent Playground in Opik. 🧵
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We want to change how teams build agents. This means: - Iterating without touching code - Letting non-engineers drive development - Continuously learning from agent traces Agent Configuration + Playground is a big step towards that goal
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Agent Configuration + Agent Playground are available today in Opik Cloud and open source. You can see the full announcement post here: comet.com/site/blog/end-to-e… Give them a try and let us know what you think!
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We want to change how teams build agents. This means: •Iterating without touching code •Letting non-engineers drive development •Continuously learning from agent traces Agent Configuration + Playground is a big step towards that goal
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Agent Configuration + Agent Playground are available today in Opik Cloud and open source. You can see the full announcement post here: comet.com/site/blog/end-to-e… Give them a try and let us know what you think!
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