Staff engineer focused on agentic engineering and Developer Experience @datadoghq · Father to two small humans

Surrey, England
Joined October 2008
Dottie, my main @bot helped me finally redesign my personal site I'm not a designer and it won't win any awards, but after a lot of iterating and sharing inspiration with her I'm so happy with how it came out 🥰 Couldn't have done this on my own fxndev.com
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What’s your context TTL?
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I'm a fan of the Hemingway bridge, stopping mid task so it’s easy to pick up tomorrow But agents mess with this Leaving them idle as I walk away feels wasteful but if I set them off I’ll keep thinking about next steps with out of date state I need Hemingway Tasks 😅 something that sets up tomorrow better Anyone have good ones?
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“No model did best in its maker’s own harness” 🤔
Model Benchmarks Are Worthless How can a model score 24% and 59% on the same 113 coding tasks? It happens when you vary the harness that wraps it. I’ve increasingly ignored most of the recent model leaderboard results. Partly from exhaustion and partly because improvements in a ranking don’t show up in the actual work. So I asked the 8090 Labs team to measure what the leaderboards skip: the model and the harness together, on real bug fixes and features from open-source projects. 8090 Labs ran 7 models through 5 harnesses. Here are a few results I didn't expect: - Anthropic's Claude Fable 5.1 scored 41% in Claude Code and 61% in OpenAI's Codex. It made 28 tool calls at the median in one and 66 in the other. - The cheapest runs weren't the cheapest work. GLM in Codex cost $0.22 a run and $0.93 per success. In Pi it cost $0.25 a run and $0.43 per success. - GLM passed a task on both attempts 51 times in one harness and 16 times in another. - GPT-5.6 Sol and Grok 4.6 barely cared which harness they were in. The bottom line is that if you're picking a model/harness combo off a model-only leaderboard, you're making a critical decision based on only half the information. 8090.ai/blog/same-model-diff…
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Is this rude? I called my grok @bot Dottie It felt like a good name to go with my Hermes agent Betty (who identifies as a friendly fox 🤷‍♂️)
🤖 Made with AI
I’ve given up waiting for dots to come to UK so testing out grokbot now Anyone have a slick way for grokbot to chat to my Hermes agent running on my local Mac mini and the other way around? I’d love it if they can delegate to each other when appropriate
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My new favourite thing to do with LLMs is to help me read fiction I’m a literal reader, maybe cause of English as 2nd language or maybe because of decades of only reading non fiction Being able to read a book and then discuss the “underlying” meaning or whatever is awesome!
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Having recommendations based on what I’ve just finished and how I found the experience is super helpful. I feel like I’m being guided to explore titles that expose me to different devices and styles I can then discuss and interpret with no pressure or judgement
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What’s most surprising which probably shouldn’t be is I can finish a book, give a high level description of what I thought and then read some of the commentary. I can talk through it and find out that I’m understanding more about the authors intent than I realised
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I’ve given up waiting for dots to come to UK so testing out grokbot now Anyone have a slick way for grokbot to chat to my Hermes agent running on my local Mac mini and the other way around? I’d love it if they can delegate to each other when appropriate
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I worry that with all of the great examples of these very capable engineers shipping a ton of work in short periods of time is that so many engineers esp young ones are very impatient or don’t know what quality looks like so they can’t build the system to ship quality fast
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I fully believe you can ship ton of great product insanely fast if you learn how to but it’s not quite as simple as many make it look
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I see a lot of “multiplayer” agent stuff Does anyone want it or is it just something to build? If it’s for anything beyond initial intent or maybe planning phases I don’t get it, what am I missing?
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Yikes first run of Haiku 5.5 against our ADEEP evals and compared to 6 Luna Mean score was 70.7% which is 3.94 points lower than Luna and at the same time almost 2x the cost and 27% slower per eval 😬 Haiku on Claude Code and Luna on Codex both with default reasoning
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Shipped a Model Guide today to help our engineers answer: What model should I use? Using the data from our internal ADEEP eval platform to give recs for models on the Pareto line or ones that score higher than avg && cost less than avg Well received so far 😅
🤖 Made with AI
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See you soon for more ships from The Ship Company.
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With models getting faster the pause is disappearing For q&a use cases I wonder if we’ll get the same BS artificial slowdown comparison sites use You know so it feels like it’s really thinking Coding is different ofc
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How’s everyone else handing over credentials to their Hermes agent? We’ve just implemented something using cloudflare tunnels but feels like something that should be solved ootb? Or is everyone just putting stuff in telegram
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Done - It opens a temporary Cloudflare link - It shows me a browser specific code - I approve my browser in Telegram - Enter the credentials - It resumes, saves the session, and closes the tunnel No remote desktop or codes in chat 👌
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How much do you care about the model latency? I never think about it but apparently a lot of people do If you do care, what would you say is your average interactive turns per pr landed? Single digits or more?
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I’ve been thinking about the different ways to use agents, how prompts change, and how trust is at the core. Pairing → micromanaging → delegating When pairing, you prompt very specifically: “Implement a function that reads from this table in the database; use columns xyz” As trust increases, you move to micromanaging: “Let’s create a new endpoint for the API. Call it blah, and use JSON API spec like the other endpoints.” Finally, when delegating: “Our users need to be able to …” Does this fit? Curious what unlocked the next level of trust for you?
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