Capability As Feasibility Knowledge Plus Executable Proof
Sources: 1 • Confidence: High • Updated: 2026-04-13 03:58
Key takeaways
- The document asserts that building software skill depends heavily on knowing what is possible and having a rough idea of how to accomplish it.
- The document asserts that collected working examples can be used as inputs for coding agents by prompting the agent to build new things by combining two or more existing examples.
- Willison publishes notes via blog/TIL posts and maintains over a thousand GitHub repositories, many of them small proof-of-concepts.
- The document asserts that coding agents make the hoarding approach more powerful by fetching and reusing source code from the internet and local codebases as context for new tasks.
- tools.simonwillison.net is described as Willison’s largest collection of LLM-assisted single-file HTML tools with embedded JavaScript and CSS that solve specific problems.
Sections
Capability As Feasibility Knowledge Plus Executable Proof
- The document asserts that building software skill depends heavily on knowing what is possible and having a rough idea of how to accomplish it.
- The document asserts that documenting a useful trick once with a working code example allows agents to consult it and solve similarly shaped projects in the future without re-deriving the technique.
- The document asserts that knowing something is theoretically possible is not equivalent to having personally seen it working as running code, and that the latter is preferable.
- The document asserts that accumulating answers to obscure or broad feasibility questions increases the likelihood of spotting problem-solving opportunities others miss.
Agentic Recombination As A Development Pattern (Examples To Integrated Tools)
- The document asserts that collected working examples can be used as inputs for coding agents by prompting the agent to build new things by combining two or more existing examples.
- Willison built a browser-based OCR tool by combining prior snippets using PDF.js to render PDF pages as images and Tesseract.js (WebAssembly) to extract text from those images in JavaScript.
- A single prompt that included two example codebases produced a working proof-of-concept HTML page that converted dropped PDFs into per-page JPEGs and ran OCR, displaying results beneath each image.
- The document asserts that iterating a few times with a model can quickly turn an LLM-generated proof-of-concept into a useful tool with lasting personal value.
Knowledge Hoard As Reusable Capital (Repos, Tils, Single-File Tools, Agent Research Outputs)
- Willison publishes notes via blog/TIL posts and maintains over a thousand GitHub repositories, many of them small proof-of-concepts.
- tools.simonwillison.net is described as Willison’s largest collection of LLM-assisted single-file HTML tools with embedded JavaScript and CSS that solve specific problems.
- The simonw/research repository is described as containing larger agent-driven examples where a coding agent researched a problem and returned working code plus a written report.
Operational Bottlenecks In Agent Toolchains (Retrieval Fidelity And Context Packaging)
- The document asserts that coding agents make the hoarding approach more powerful by fetching and reusing source code from the internet and local codebases as context for new tasks.
- Willison often instructs agents to clone his public repositories to /tmp and mine them for examples to apply to new projects.
- When using Claude Code, specifying curl can be necessary because the default WebFetch tool summarizes pages instead of returning raw HTML.
Unknowns
- How often does the recombination prompting pattern produce correct, maintainable integrations across different problem types beyond the OCR example?
- What is the measured time/effort saved (or additional time incurred) by maintaining the hoard of repositories, notes, and single-file tools?
- What are the failure modes when agents fetch and reuse external or local code, including incorrect dependency assumptions, licensing constraints, or security risks?
- What retrieval and context-delivery practices are sufficient to ensure fidelity (raw source, correct versions, complete dependencies) when using agent toolchains?
- What organizational process best supports sharing, searching, and maintaining a growing library of executable examples across a team rather than an individual?