{
  "source_file": "0930",
  "source_platform": "Substack",
  "author": "AI by Hand ✍️ Prof. Tom Yeh",
  "title_listed": "QKV Projection by Hand",
  "keywords": "QKV投影,注意力",
  "domain": "大模型算法",
  "content_type": "教程",
  "is_paid_flag": "否",
  "url": "https://www.byhand.ai/p/library-models-attention-qkv",
  "publish_date": "2025-01",
  "corpus_stage": "预训练/SFT",
  "notes": "手算QKV投影",
  "id": "6a61339d08f3",
  "collected_at": "2026-10-01T20:45:44",
  "title": "AI by Hand ✍️ | Prof. Tom Yeh | Substack",
  "body_markdown": "[![AI by Hand ✍️](https://substackcdn.com/image/fetch/$s_!fOmN!,w_40,h_40,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F618d59fa-9b8f-4814-8d16-f29c2f23ae53_371x371.png)](https://www.byhand.ai/)\n# [AI by Hand ✍️](https://www.byhand.ai/)\nSubscribeSign in\n[Home](https://www.byhand.ai/)\n[Frontier](https://www.byhand.ai/t/frontier)\n[Foundation](https://www.byhand.ai/t/foundation)\n[Library](https://www.byhand.ai/p/library)\n## Page not found\nLatestTopDiscussions\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-series-sheets-rnn)\n[From a small neuron to a small language model](https://www.byhand.ai/p/library-series-sheets-rnn)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](../images/013.jpeg)\n[Small Language Model](https://www.byhand.ai/p/library-sheets-rnn-everything)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-everything)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](../images/031.jpeg)\n[Loss](https://www.byhand.ai/p/library-sheets-rnn-loss)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-loss)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](../images/body-71b03f8628af53f6a41c.jpeg)\n[Autoregressive](https://www.byhand.ai/p/library-sheets-rnn-autoregressive)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-autoregressive)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](../images/body-2b6c199cfb9f8d1b0908.jpeg)\n[Tokens](https://www.byhand.ai/p/library-sheets-rnn-tokens)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-tokens)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](../images/body-cfeab5d9caafe940992a.jpeg)\n[Seq2Seq](https://www.byhand.ai/p/library-sheets-rnn-seq2seq)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-seq2seq)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](../images/body-6893cd6ea589e38ea314.jpeg)\n[Depth](https://www.byhand.ai/p/library-sheets-rnn-depth)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-depth)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](../images/body-9286230f5d89b79c2d42.jpeg)\n[Outputs](https://www.byhand.ai/p/library-sheets-rnn-outputs)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-outputs)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](../images/body-cc10f91b37b3f33d7144.jpeg)\n[Size](https://www.byhand.ai/p/library-sheets-rnn-size)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-size)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](../images/body-18aa0c4d64ad68ad40fb.jpeg)\n[Recurrence](https://www.byhand.ai/p/library-sheets-rnn-recurrence)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-recurrence)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](../images/body-615486b632cb86aff7d4.jpeg)\n[AI by Hand ✍️ Yantra Jnana Award](https://www.byhand.ai/p/library-newsletter-challenges-yantra-jnana-challenge)\n[Teach AI by Hand in India’s Languages](https://www.byhand.ai/p/library-newsletter-challenges-yantra-jnana-challenge)\nSep 4 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n25\n3\n![](../images/body-194ac803361a1f80393d.jpeg)\n### August 2026\n[Counting AI by Hand ✍️ ~ Recordings](https://www.byhand.ai/p/library-series-videos-counting-ai-by-hand)\n[Mohsena Ashraf on measuring what AI costs, in Excel](https://www.byhand.ai/p/library-series-videos-counting-ai-by-hand)\nAug 22 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n31\n1\n1\n![](../images/body-81461de8e2501d5dab4c.jpeg)\n[Loop Engineering (coming soon, Sep 3, 2026)](https://www.byhand.ai/p/library-videos-counting-ai-by-hand-loop-engineering)\n[Counting AI by Hand ✍️ Lecture Series by Mohsena](https://www.byhand.ai/p/library-videos-counting-ai-by-hand-loop-engineering)\nAug 22 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n3\n[Agent Tokens (Jul 14, 2026)](https://www.byhand.ai/p/library-videos-counting-ai-by-hand-agent-tokens)\n[Counting AI by Hand ✍️ Lecture Series by Mohsena](https://www.byhand.ai/p/library-videos-counting-ai-by-hand-agent-tokens)\nAug 22 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n3\n1\n![](../images/body-febaf3b8c4ed9512620e.jpeg)\n[Transformer Ops (Jun 23, 2026)](https://www.byhand.ai/p/library-videos-counting-ai-by-hand-transformer-ops)\n[Counting AI by Hand ✍️ Lecture Series by Mohsena](https://www.byhand.ai/p/library-videos-counting-ai-by-hand-transformer-ops)\nAug 22 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n2\n1\n![](../images/body-81461de8e2501d5dab4c.jpeg)\n[Kimi 3 ~ New Seminar Recording](https://www.byhand.ai/p/library-videos-seminars-2026-kimi-3-seminar-recording)\n[AI by Hand ✍️ Seminars](https://www.byhand.ai/p/library-videos-seminars-2026-kimi-3-seminar-recording)\nAug 20 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n29\n1\n2\n![](../images/body-a093b0c0f3afcb809354.jpeg)\n[Context Problems](https://www.byhand.ai/p/library-series-agents-context)\n[Agentic AI by hand ✍️](https://www.byhand.ai/p/library-series-agents-context)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n3\n1\n![](../images/body-813351e60b94e92f7513.jpeg)\n[Cost Forecast](https://www.byhand.ai/p/library-agents-context-a-long-conversation)\n[Budgeting a Long Session](https://www.byhand.ai/p/library-agents-context-a-long-conversation)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n2\n![](../images/body-389b7d711514a7745d1b.jpeg)\n[Quadratic Cost](https://www.byhand.ai/p/library-agents-context-adding-up-the-turns)\n[Adding Up the Turns](https://www.byhand.ai/p/library-agents-context-adding-up-the-turns)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n2\n![](../images/body-27584192387e1d43b8f7.jpeg)\n[Context Tax](https://www.byhand.ai/p/library-agents-context-paying-for-the-past)\n[Paying for the Past](https://www.byhand.ai/p/library-agents-context-paying-for-the-past)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n2\n![](../images/body-a33cbf83340d5f789c46.jpeg)\n[Retrieval Cost](https://www.byhand.ai/p/library-agents-context-retrieved-chunks-are-input)\n[Retrieved Chunks Are Input](https://www.byhand.ai/p/library-agents-context-retrieved-chunks-are-input)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n1\n![](../images/body-48ff7aa014e712ce707a.jpeg)\n[Stateless API](https://www.byhand.ai/p/library-agents-context-what-each-turn-sends)\n[Resending the Context](https://www.byhand.ai/p/library-agents-context-what-each-turn-sends)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n2\n![](../images/body-8697823432decfe4082b.jpeg)\n[Verbatim Tail](https://www.byhand.ai/p/library-agents-context-what-compaction-keeps)\n[Keeping the recent rounds whole](https://www.byhand.ai/p/library-agents-context-what-compaction-keeps)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](../images/body-d0049c0aeb795c41de72.jpeg)\n[The Compaction Threshold](https://www.byhand.ai/p/library-agents-context-when-to-compact)\n[Picking the number from a round](https://www.byhand.ai/p/library-agents-context-when-to-compact)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](../images/body-ffcce59723a05cf35ddc.jpeg)\n© 2026 Tom Yeh · [Privacy](https://substack.com/privacy) ∙ [Terms](https://substack.com/tos) ∙ [Collection notice](https://substack.com/ccpa#personal-data-collected)\n[ Start your Substack](https://substack.com/signup?utm_source=substack&utm_medium=web&utm_content=footer)[Get the app](https://substack.com/app/app-store-redirect?utm_campaign=app-marketing&utm_content=web-footer-button)\n[Substack](https://substack.com) is the home for great culture\n",
  "metadata": {
    "title": "AI by Hand ✍️ | Prof. Tom Yeh | Substack",
    "description": "Math, Algorithms, Architectures, by hand. Click to read AI by Hand ✍️, by Prof. Tom Yeh, a Substack publication with tens of thousands of subscribers.",
    "keywords": null,
    "author": "Prof. Tom Yeh",
    "og:type": "article",
    "og:title": "AI by Hand ✍️ | Prof. Tom Yeh | Substack",
    "og:description": "Math, Algorithms, Architectures, by hand. Click to read AI by Hand ✍️, by Prof. Tom Yeh, a Substack publication with tens of thousands of subscribers.",
    "og:image": "https://substackcdn.com/image/fetch/$s_!uug6!,f_auto,q_auto:best,fl_progressive:steep/https%3A%2F%2Faibyhand.substack.com%2Ftwitter%2Fsubscribe-card.jpg%3Fv%3D-636237388%26version%3D9",
    "og:url": "https://www.byhand.ai/library-models-attention-qkv",
    "twitter:title": "AI by Hand ✍️ | Prof. Tom Yeh | Substack",
    "twitter:description": "Math, Algorithms, Architectures, by hand. Click to read AI by Hand ✍️, by Prof. Tom Yeh, a Substack publication with tens of thousands of subscribers.",
    "twitter:image": "https://substackcdn.com/image/fetch/$s_!uug6!,f_auto,q_auto:best,fl_progressive:steep/https%3A%2F%2Faibyhand.substack.com%2Ftwitter%2Fsubscribe-card.jpg%3Fv%3D-636237388%26version%3D9",
    "twitter:card": "summary_large_image"
  },
  "paywall": {
    "listed_paid": false,
    "detected": false,
    "marker": "",
    "public_only": false,
    "policy": "付费/会员内容只保留页面公开可见部分，不绕过付费墙"
  },
  "crawl": {
    "success": true,
    "status_code": 302,
    "error": ""
  },
  "code_blocks": [],
  "images": [
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!yr-V!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fe57c087f-8c87-4a74-ab1a-dc593576af50_2000x2639.jpeg",
      "bytes": 15718,
      "reused": true,
      "local_path": "attachments/6a61339d08f3/images/013.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!yr-V!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fe57c087f-8c87-4a74-ab1a-dc593576af50_2000x2639.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!kHPS!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fe755be7e-a79e-41fd-8b85-2c61ab276374_8300x10988.jpeg",
      "bytes": 15091,
      "reused": true,
      "local_path": "attachments/6a61339d08f3/images/031.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!kHPS!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fe755be7e-a79e-41fd-8b85-2c61ab276374_8300x10988.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!fTVM!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1cf75a1e-b944-449e-b973-bce59412e61f_1092x956.jpeg",
      "bytes": 14838,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-71b03f8628af53f6a41c.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!fTVM!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1cf75a1e-b944-449e-b973-bce59412e61f_1092x956.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!DiFE!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F29c79ce3-2114-45f5-af5d-4344704bc8dc_1160x812.jpeg",
      "bytes": 31272,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-2b6c199cfb9f8d1b0908.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!DiFE!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F29c79ce3-2114-45f5-af5d-4344704bc8dc_1160x812.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!IZkY!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2443ab53-0422-445d-8792-2bee1d1edf97_956x1100.jpeg",
      "bytes": 27894,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-cfeab5d9caafe940992a.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!IZkY!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2443ab53-0422-445d-8792-2bee1d1edf97_956x1100.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!Sw5t!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Ff190f518-1a70-4dfb-a422-ce1567b80578_1160x908.jpeg",
      "bytes": 29850,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-6893cd6ea589e38ea314.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!Sw5t!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Ff190f518-1a70-4dfb-a422-ce1567b80578_1160x908.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!OIFJ!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F93b33e27-627e-4f6f-8c83-c8b81b6cc9a6_1092x1004.jpeg",
      "bytes": 16114,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-9286230f5d89b79c2d42.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!OIFJ!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F93b33e27-627e-4f6f-8c83-c8b81b6cc9a6_1092x1004.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!8tMS!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F216dc7ee-add2-4382-b42c-287f57b8bd59_1160x860.jpeg",
      "bytes": 32606,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-cc10f91b37b3f33d7144.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!8tMS!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F216dc7ee-add2-4382-b42c-287f57b8bd59_1160x860.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!IfAz!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0a84676d-d18b-4bde-9e79-93351ad50842_1160x812.jpeg",
      "bytes": 31841,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-18aa0c4d64ad68ad40fb.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!IfAz!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0a84676d-d18b-4bde-9e79-93351ad50842_1160x812.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!nksh!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F3902b7d3-0706-4139-b958-035ed0ac85bd_480x620.jpeg",
      "bytes": 12805,
      "reused": false,
      "content_type": "image/png",
      "local_path": "attachments/6a61339d08f3/images/body-615486b632cb86aff7d4.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!nksh!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F3902b7d3-0706-4139-b958-035ed0ac85bd_480x620.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!RddY!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F17fa1a6e-6ded-42f5-85eb-d3b59a8936bc_992x931.jpeg",
      "bytes": 18033,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-194ac803361a1f80393d.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!RddY!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F17fa1a6e-6ded-42f5-85eb-d3b59a8936bc_992x931.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!ebNU!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F5c3a92ce-da27-4497-af16-5ba4ecb51b14_2409x872.jpeg",
      "bytes": 18149,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-81461de8e2501d5dab4c.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!ebNU!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F5c3a92ce-da27-4497-af16-5ba4ecb51b14_2409x872.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!8Rno!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fe437af92-fe67-439a-b5b5-127a6b67b849_2409x872.jpeg",
      "bytes": 19119,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-febaf3b8c4ed9512620e.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!8Rno!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fe437af92-fe67-439a-b5b5-127a6b67b849_2409x872.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!L8wb!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F50f97871-652e-45f7-9c06-e279ec32a9d4_1920x1080.jpeg",
      "bytes": 16395,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-a093b0c0f3afcb809354.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!L8wb!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F50f97871-652e-45f7-9c06-e279ec32a9d4_1920x1080.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!zPTv!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F339fc974-29b2-4b28-98b6-8a49088a6bd8_1845x800.jpeg",
      "bytes": 15185,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-813351e60b94e92f7513.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!zPTv!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F339fc974-29b2-4b28-98b6-8a49088a6bd8_1845x800.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!hKqy!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F3dae594e-e8a2-47eb-951b-454357a44c25_1845x2400.jpeg",
      "bytes": 14272,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-389b7d711514a7745d1b.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!hKqy!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F3dae594e-e8a2-47eb-951b-454357a44c25_1845x2400.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!Uf7S!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F99ddcb2d-a9e7-418d-90ca-faeb0872c7e7_1845x2400.jpeg",
      "bytes": 13107,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-27584192387e1d43b8f7.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!Uf7S!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F99ddcb2d-a9e7-418d-90ca-faeb0872c7e7_1845x2400.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!onsu!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2cb5d8e3-202a-444b-9063-32bc5a1dd254_1845x2400.jpeg",
      "bytes": 13437,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-a33cbf83340d5f789c46.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!onsu!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2cb5d8e3-202a-444b-9063-32bc5a1dd254_1845x2400.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!aqtf!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F49a09124-42b6-4a4e-afc0-56cdb8f58cae_1845x2400.jpeg",
      "bytes": 14260,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-48ff7aa014e712ce707a.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!aqtf!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F49a09124-42b6-4a4e-afc0-56cdb8f58cae_1845x2400.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!9MHi!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F74b3f734-35bc-40e5-b679-1d194bae3c35_1845x2400.jpeg",
      "bytes": 12985,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-8697823432decfe4082b.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!9MHi!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F74b3f734-35bc-40e5-b679-1d194bae3c35_1845x2400.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!oheS!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdcd29af1-eb8f-4771-9e04-4af42439a92c_1845x2400.jpeg",
      "bytes": 13603,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-d0049c0aeb795c41de72.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!oheS!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdcd29af1-eb8f-4771-9e04-4af42439a92c_1845x2400.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    },
    {
      "status": "ok",
      "url": "https://substackcdn.com/image/fetch/$s_!Yicj!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8be296f2-63c9-43ac-bef8-d655fc618e7b_1845x2400.jpeg",
      "bytes": 13704,
      "reused": false,
      "content_type": "image/jpeg",
      "local_path": "attachments/6a61339d08f3/images/body-ffcce59723a05cf35ddc.jpeg",
      "src": "https://substackcdn.com/image/fetch/$s_!Yicj!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8be296f2-63c9-43ac-bef8-d655fc618e7b_1845x2400.jpeg",
      "alt": "",
      "downloaded": true,
      "discovery": "saved_markdown"
    }
  ],
  "audio": [],
  "videos": [],
  "links": [
    {
      "type": "internal",
      "href": "https://www.byhand.ai/"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/t/frontier"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/t/foundation"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-series-sheets-rnn"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-sheets-rnn-everything"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-sheets-rnn-loss"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-sheets-rnn-autoregressive"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-sheets-rnn-tokens"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-sheets-rnn-seq2seq"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-sheets-rnn-depth"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-sheets-rnn-outputs"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-sheets-rnn-size"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-sheets-rnn-recurrence"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-newsletter-challenges-yantra-jnana-challenge"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-series-videos-counting-ai-by-hand"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-videos-counting-ai-by-hand-loop-engineering"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-videos-counting-ai-by-hand-agent-tokens"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-videos-counting-ai-by-hand-transformer-ops"
    },
    {
      "type": "internal",
      "href": "https://www.byhand.ai/p/library-videos-seminars-2026-kimi-3-seminar-recording"
    },
    {
      "type": "external",
      "href": "https://substack.com/@tomyeh"
    },
    {
      "type": "external",
      "href": "https://substack.com/privacy"
    },
    {
      "type": "external",
      "href": "https://substack.com/tos"
    },
    {
      "type": "external",
      "href": "https://substack.com/ccpa"
    },
    {
      "type": "external",
      "href": "https://substack.com/signup"
    },
    {
      "type": "external",
      "href": "https://substack.com/app/app-store-redirect"
    },
    {
      "type": "external",
      "href": "https://substack.com"
    }
  ],
  "repair_version": 2,
  "repaired_at": "2026-10-20T17:33:58Z",
  "source_url": "https://www.byhand.ai/p/library-models-attention-qkv",
  "delivery_status": "unverified",
  "discovery_status": "http_404",
  "missing_reason": "http_404",
  "repair_error": "",
  "actual_video_files": [],
  "expected_saved_body_images": 22,
  "image_discovery": "saved_markdown",
  "source_body_markdown": "[![AI by Hand ✍️](https://substackcdn.com/image/fetch/$s_!fOmN!,w_40,h_40,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F618d59fa-9b8f-4814-8d16-f29c2f23ae53_371x371.png)](https://www.byhand.ai/)\n# [AI by Hand ✍️](https://www.byhand.ai/)\nSubscribeSign in\n[Home](https://www.byhand.ai/)\n[Frontier](https://www.byhand.ai/t/frontier)\n[Foundation](https://www.byhand.ai/t/foundation)\n[Library](https://www.byhand.ai/p/library)\n## Page not found\nLatestTopDiscussions\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-series-sheets-rnn)\n[From a small neuron to a small language model](https://www.byhand.ai/p/library-series-sheets-rnn)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](https://substackcdn.com/image/fetch/$s_!yr-V!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fe57c087f-8c87-4a74-ab1a-dc593576af50_2000x2639.jpeg)\n[Small Language Model](https://www.byhand.ai/p/library-sheets-rnn-everything)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-everything)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](https://substackcdn.com/image/fetch/$s_!kHPS!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fe755be7e-a79e-41fd-8b85-2c61ab276374_8300x10988.jpeg)\n[Loss](https://www.byhand.ai/p/library-sheets-rnn-loss)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-loss)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](https://substackcdn.com/image/fetch/$s_!fTVM!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1cf75a1e-b944-449e-b973-bce59412e61f_1092x956.jpeg)\n[Autoregressive](https://www.byhand.ai/p/library-sheets-rnn-autoregressive)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-autoregressive)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](https://substackcdn.com/image/fetch/$s_!DiFE!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F29c79ce3-2114-45f5-af5d-4344704bc8dc_1160x812.jpeg)\n[Tokens](https://www.byhand.ai/p/library-sheets-rnn-tokens)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-tokens)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](https://substackcdn.com/image/fetch/$s_!IZkY!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2443ab53-0422-445d-8792-2bee1d1edf97_956x1100.jpeg)\n[Seq2Seq](https://www.byhand.ai/p/library-sheets-rnn-seq2seq)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-seq2seq)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](https://substackcdn.com/image/fetch/$s_!Sw5t!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Ff190f518-1a70-4dfb-a422-ce1567b80578_1160x908.jpeg)\n[Depth](https://www.byhand.ai/p/library-sheets-rnn-depth)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-depth)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](https://substackcdn.com/image/fetch/$s_!OIFJ!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F93b33e27-627e-4f6f-8c83-c8b81b6cc9a6_1092x1004.jpeg)\n[Outputs](https://www.byhand.ai/p/library-sheets-rnn-outputs)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-outputs)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](https://substackcdn.com/image/fetch/$s_!8tMS!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F216dc7ee-add2-4382-b42c-287f57b8bd59_1160x860.jpeg)\n[Size](https://www.byhand.ai/p/library-sheets-rnn-size)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-size)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](https://substackcdn.com/image/fetch/$s_!IfAz!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0a84676d-d18b-4bde-9e79-93351ad50842_1160x812.jpeg)\n[Recurrence](https://www.byhand.ai/p/library-sheets-rnn-recurrence)\n[RNNs by Hand, in Excel](https://www.byhand.ai/p/library-sheets-rnn-recurrence)\nSep 27 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](https://substackcdn.com/image/fetch/$s_!nksh!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F3902b7d3-0706-4139-b958-035ed0ac85bd_480x620.jpeg)\n[AI by Hand ✍️ Yantra Jnana Award](https://www.byhand.ai/p/library-newsletter-challenges-yantra-jnana-challenge)\n[Teach AI by Hand in India’s Languages](https://www.byhand.ai/p/library-newsletter-challenges-yantra-jnana-challenge)\nSep 4 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n25\n3\n![](https://substackcdn.com/image/fetch/$s_!RddY!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F17fa1a6e-6ded-42f5-85eb-d3b59a8936bc_992x931.jpeg)\n### August 2026\n[Counting AI by Hand ✍️ ~ Recordings](https://www.byhand.ai/p/library-series-videos-counting-ai-by-hand)\n[Mohsena Ashraf on measuring what AI costs, in Excel](https://www.byhand.ai/p/library-series-videos-counting-ai-by-hand)\nAug 22 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n31\n1\n1\n![](https://substackcdn.com/image/fetch/$s_!ebNU!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F5c3a92ce-da27-4497-af16-5ba4ecb51b14_2409x872.jpeg)\n[Loop Engineering (coming soon, Sep 3, 2026)](https://www.byhand.ai/p/library-videos-counting-ai-by-hand-loop-engineering)\n[Counting AI by Hand ✍️ Lecture Series by Mohsena](https://www.byhand.ai/p/library-videos-counting-ai-by-hand-loop-engineering)\nAug 22 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n3\n[Agent Tokens (Jul 14, 2026)](https://www.byhand.ai/p/library-videos-counting-ai-by-hand-agent-tokens)\n[Counting AI by Hand ✍️ Lecture Series by Mohsena](https://www.byhand.ai/p/library-videos-counting-ai-by-hand-agent-tokens)\nAug 22 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n3\n1\n![](https://substackcdn.com/image/fetch/$s_!8Rno!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fe437af92-fe67-439a-b5b5-127a6b67b849_2409x872.jpeg)\n[Transformer Ops (Jun 23, 2026)](https://www.byhand.ai/p/library-videos-counting-ai-by-hand-transformer-ops)\n[Counting AI by Hand ✍️ Lecture Series by Mohsena](https://www.byhand.ai/p/library-videos-counting-ai-by-hand-transformer-ops)\nAug 22 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n2\n1\n![](https://substackcdn.com/image/fetch/$s_!ebNU!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F5c3a92ce-da27-4497-af16-5ba4ecb51b14_2409x872.jpeg)\n[Kimi 3 ~ New Seminar Recording](https://www.byhand.ai/p/library-videos-seminars-2026-kimi-3-seminar-recording)\n[AI by Hand ✍️ Seminars](https://www.byhand.ai/p/library-videos-seminars-2026-kimi-3-seminar-recording)\nAug 20 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n29\n1\n2\n![](https://substackcdn.com/image/fetch/$s_!L8wb!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F50f97871-652e-45f7-9c06-e279ec32a9d4_1920x1080.jpeg)\n[Context Problems](https://www.byhand.ai/p/library-series-agents-context)\n[Agentic AI by hand ✍️](https://www.byhand.ai/p/library-series-agents-context)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n3\n1\n![](https://substackcdn.com/image/fetch/$s_!zPTv!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F339fc974-29b2-4b28-98b6-8a49088a6bd8_1845x800.jpeg)\n[Cost Forecast](https://www.byhand.ai/p/library-agents-context-a-long-conversation)\n[Budgeting a Long Session](https://www.byhand.ai/p/library-agents-context-a-long-conversation)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n2\n![](https://substackcdn.com/image/fetch/$s_!hKqy!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F3dae594e-e8a2-47eb-951b-454357a44c25_1845x2400.jpeg)\n[Quadratic Cost](https://www.byhand.ai/p/library-agents-context-adding-up-the-turns)\n[Adding Up the Turns](https://www.byhand.ai/p/library-agents-context-adding-up-the-turns)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n2\n![](https://substackcdn.com/image/fetch/$s_!Uf7S!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F99ddcb2d-a9e7-418d-90ca-faeb0872c7e7_1845x2400.jpeg)\n[Context Tax](https://www.byhand.ai/p/library-agents-context-paying-for-the-past)\n[Paying for the Past](https://www.byhand.ai/p/library-agents-context-paying-for-the-past)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n2\n![](https://substackcdn.com/image/fetch/$s_!onsu!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2cb5d8e3-202a-444b-9063-32bc5a1dd254_1845x2400.jpeg)\n[Retrieval Cost](https://www.byhand.ai/p/library-agents-context-retrieved-chunks-are-input)\n[Retrieved Chunks Are Input](https://www.byhand.ai/p/library-agents-context-retrieved-chunks-are-input)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n1\n![](https://substackcdn.com/image/fetch/$s_!aqtf!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F49a09124-42b6-4a4e-afc0-56cdb8f58cae_1845x2400.jpeg)\n[Stateless API](https://www.byhand.ai/p/library-agents-context-what-each-turn-sends)\n[Resending the Context](https://www.byhand.ai/p/library-agents-context-what-each-turn-sends)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n2\n![](https://substackcdn.com/image/fetch/$s_!9MHi!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F74b3f734-35bc-40e5-b679-1d194bae3c35_1845x2400.jpeg)\n[Verbatim Tail](https://www.byhand.ai/p/library-agents-context-what-compaction-keeps)\n[Keeping the recent rounds whole](https://www.byhand.ai/p/library-agents-context-what-compaction-keeps)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](https://substackcdn.com/image/fetch/$s_!oheS!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdcd29af1-eb8f-4771-9e04-4af42439a92c_1845x2400.jpeg)\n[The Compaction Threshold](https://www.byhand.ai/p/library-agents-context-when-to-compact)\n[Picking the number from a round](https://www.byhand.ai/p/library-agents-context-when-to-compact)\nAug 19 • [Prof. Tom Yeh](https://substack.com/@tomyeh)\n![](https://substackcdn.com/image/fetch/$s_!Yicj!,w_320,h_213,c_fill,f_auto,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8be296f2-63c9-43ac-bef8-d655fc618e7b_1845x2400.jpeg)\n© 2026 Tom Yeh · [Privacy](https://substack.com/privacy) ∙ [Terms](https://substack.com/tos) ∙ [Collection notice](https://substack.com/ccpa#personal-data-collected)\n[ Start your Substack](https://substack.com/signup?utm_source=substack&utm_medium=web&utm_content=footer)[Get the app](https://substack.com/app/app-store-redirect?utm_campaign=app-marketing&utm_content=web-footer-button)\n[Substack](https://substack.com) is the home for great culture\n",
  "body_base_path": "attachments/6a61339d08f3/pages/",
  "body_markdown_path": "attachments/6a61339d08f3/pages/archived-body.md",
  "local_html": "attachments/6a61339d08f3/pages/archived-body.html",
  "body_source": "prior_capture"
}