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James Clarke

@jacla

Engineering at @polytomic. Previously at @getzaius. Past life: Natural Language Processing and Machine Learning.

 Medford, MA
jamesclarke.net
Joined March 2007
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  • Following124
  • Followers294
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Photo by James Clarke (@jacla)Photo by James Clarke (@jacla)Photo by James Clarke (@jacla)Photo by James Clarke (@jacla)Photo by James Clarke (@jacla)Photo by James Clarke (@jacla)Photo by James Clarke (@jacla)Photo by James Clarke (@jacla)Photo by James Clarke (@jacla)
7:09 is @polytomic time.
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James Clarke retweeted
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James Clarke@jaclaOct 22
Replying to @tylercowen
On AI vs SI. In the 1800s, they had "artificial ice". Thankfully they didn't rename it super ice. Now we just have ice.
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Paper prototyping eink family calendar and temperature display.
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Indoors, outside, inside.
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First frost
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Morning run. Still no time to bike.
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The mess of agent harnesses and MCP clients is ridiculous. Feels like the browser compatibility wars all over again. I fell down the rabbit hole. Building a MCP server? Test what different harnesses actually support with What the Harness. what-the-harness.polytomic.c…
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Using @modemdev made me realize this is table stakes. It is amazing how many products fail here.
Ben Vinegar (@bentlegen) profile pictureBen Vinegar
@bentlegenOct 6
it's 2026 if your agent can't explain how your product works, you need to fix it
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Fall is happening.
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I think you need to understand TikTok and instagram to use Aura.
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MCP token trap: don't do this! Some harnesses feed both content and structuredContent to the model. Duplicate the payload, duplicate the tokens. Test your MCP output across harnesses. Browser compatibility testing is back, just with agents.
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more replies
Use this quick test MCP server: mcp-output-probe.vercel.app/…
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Prompt: Call probe_both, probe_text_only, and probe_structured_only once each. Report each probe_id and exact markers you received. Mark missing values "not visible"; don't guess or fetch separately.
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