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Show HN: Showboat and Rodney, so agents can demo what they've built
I was a bit confused as to how everything works until I read it in detail. Really cool tools, but I think one thing that would help in the introduction is: saying explicitly that the generated .md document is for you (the user) to read through, observe the output of the CLI call, and ensure that the output matches what you would expect.

It's basically an automated test, but at a higher abstraction level and with manual verification--using CLI tools rather than a test harness. Really great work!

A bit like jupyter notebooks, isn't it?
  • simonw
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  • 6 minutes ago
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Yes, very much so. It's a much thinner, less feature-rich alternative.

It would be interesting to experiment with Jupyter notebooks as an alternative that could work in Claude Code for web.

I had a poke around just now and couldn't find an existing CLI tool that lets you build those up a section at a time in the same way as Showboat. I did find this Python library though:

    uv run --with nbformat python -c '
    import nbformat
    nb = nbformat.v4.new_notebook()
    nb.cells.append(nbformat.v4.new_markdown_cell("# NBTerm Exploration"))
    nb.cells.append(nbformat.v4.new_code_cell("import sys\nprint(f\"Python {sys.version}\")"))
    nb.cells.append(nbformat.v4.new_code_cell("x = [i**2 for i in range(10)]\nprint(x)"))
    nb.cells.append(nbformat.v4.new_code_cell("sum(x)"))
    with open("demo.ipynb", "w") as f:
        nbformat.write(nb, f)
    '
So you could tell the agent to run code like that and then inspect the `demo.ipynb` notebook later on.
If agents can generate text so easily, why would they be limited to Markdown instead of reStructuredText, AsciiDoc, or LaTeX which have rich features that help users understand text? I can understand developers refusing to adopt proper formats for documentation, but this seems odd for the bots. It doesn’t even generate the correct syntax block in Markdown using “bash” instead of “sh-session”.
I dunno. I’ve written a bit of LaTeX but does it really shine in this context? IMO the real advantage it has is that it can allow the user to express more complicated intents than Markdown (weird phrasing—my natural instinct was to call LaTeX more precise than Markdown, but Markdown is pretty precise for describing the type of file that it is good at…).

Anyway LLMs don’t have underlying intent so maybe it is fine to just let them express what they can in Markdown?

Markdown has the widest tool compatibility - GitHub renders it, so does VS Code and many other editors and file hosts.

I didn't know about sh-session, is that documented anywhere?

I think its primarily because that is the most common formatting in every editor now? I could be wrong. Markdown has become the standard for README files for over a decade now.
Winning a popularity contest doesn’t mean it’s good. That is the worst part of about these things as they just generate the most common denominator type code/tooling while also repeating anti-patterns/mistakes like the bash vs. sh-session/console issue I pointed out. Garbage in has been so much garbage out unfortunately.
Never said it was good, just making an observation that Markdown is most likely to be available to render OOTB in more editors. I don't think Markdown is bad necessarily either. It's "good enough" for simple document.
  • johnfn
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Out of curiosity, what is the advantage of using Rodney when Playwright has the same set of features and AI understands how to write a Playwright script very well?
  • simonw
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Maybe not a lot.

Showboat documents look neater if there are single one-line commands that do something useful. Dumping a full Playwright script into a cell is less readable.

Showboat also has a special feature where you can embed an image directly in the document by running:

  showboat image doc.md 'rodney screenshot'
The command you call should return a path to an image file as the last line of output. Rodney does exactly that.

It may well turn out that Rodney is unnecessary and people find better patterns using Showboat with existing tools like playwright-cli - in which case it won't matter because Showboat and Rodney aren't coupled to each other at all.

Showboat is definitely the more significant of the two projects.

I'll be sure to try these out. I've been building my own alternative to Beads with a concept called "gates" which do not let you close tasks as complete until a gate passes. Would love to throw these in as "gates" for my current workflow.
Wait, why should an LLM simply not just write directly to the markdown file instead of going through the extra step of using a cli tool which is basically `echo 'something' >> file.md` but with templates that should really be in a prompt instead of a being in a compiled binary? Did Claude come up with the idea for this as well?

Also, I am sure you must already know about Playwright mcp so why this? If your goal isn't to make the cli human-friendly, which is the only advantage clis have over mcps doing the same thing, then why not just use the mcp? It doesn't even handle multiple sessions and has a single global state file––this is slop.

  • simonw
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  • 22 minutes ago
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Because I don't want it to write to the markdown file directly. I want it to tell me the command it runs and I then run that command and write both the command and the output to the file.

Otherwise it's just writing a document, not building a demo you can review.

As far as I can tell you can't hook MCPs up to Claude Code for web.

I originally planned to support separate sessions but decided to leave that out for the initial release. I've opened an issue for that here: https://github.com/simonw/rodney/issues/6

Very interesting! I encountered the problems these tools are trying to tackle just recently while trying to guide an agent into creating an in-browser tool for me. Closing the loop on a web interface isn't as simple as CLI-only tools. I should give this a try.

It's also interesting that you've shifted to Go for your agent-coded CLI tools, Simon.

I'm dabbling with Go at the moment for small tools, mainly as an excuse to learn a new language but also because having a single standalone binary is convenient for shuttling these tiny little tools around.

... but then I'm mostly running them with "uvx name-of-tool" because it turns out Python's packaging infrastructure for binary tools is so good!

Right, standalone binaries for CLI tools is great. And if one has Go installed, they can just `go run ...` any tool from its GitHub path, all installation/build/caching happens automagically (meaning the execution is immediate after the first run).

But I can definitely see how someone with `uv` muscle memory wants everything in the same command.

`uv` is the best thing that happened to the Python ecosystem since... I don't know... maybe Numpy.

If you're coming from the Python world, definitely. I find `go install github.com/simonw/rodney@latest` equally easy. :D Although you need the Go tooling installed, of course. But so much agree, Go is great for CLIs!
go-rod has been instrumental to my agentic coding loops too. Some uses:

- E2E testing of browser components

- Taking screenshots before and after and having Claude look at them to double check things

- Driving it with an API and CLI as a headless browser

Will definitely give Rodney a look.

See also (the confusingly named) playwright-cli

https://github.com/microsoft/playwright-cli

Different from the cli used for running tests etc that comes bundled with PlayWright

Sample use:

  playwright-cli open https://demo.playwright.dev/todomvc/ --headed
  playwright-cli type "Buy groceries"
  playwright-cli press Enter
  playwright-cli type "Water flowers"
  playwright-cli press Enter
  playwright-cli check e21
  playwright-cli check e35
  playwright-cli screenshot
Oh, I hadn't seen that one either, thanks for sharing. Here I am still using the Chrome Devtools MCP like a caveman. :D
Yeah that's an excellent option for this kind of thing too.
Google's antigravity does this automatically by creating Task & Walkthrough artifacts.
Sounds like both of these tools could be one shot by either Claude or Codex.

Or alternatively, just be a skill versus a tool.

My “agents” already demo stuff all the time by just being prompted to do so. I have notations in my standard Agents.md for how I want my documentation, testing etc.

They kind of were one-shotted by Claude. The value is in coming up with a consistent design and good enough --help that you can prompt:

  Run uvx showboat --help and
  uvx rodney --help and use those
  tools to demo the feature you built
The help text effectively doubles as a skill.
I guess it would still make sense to have "demo" and "browser-use" skills, so that the agent can reach for them proactively? I always try to remove as much friction as possible for myself, one little bit at a time.
My problem is that I work in dozens of different repos generally using Claude Code for web, which doesn't have a way to install extra global skills yet.

I don't want to duplicate my skills into all those repos (and keep them updated) so I prefer the "uvx tool --help" pattern.

That's actually one of the things that has kept me from using Claude Code web (that, and I often need a Chrome browser for the agent). But they must be working on it.

I saw an MCP I've set up on claude.ai show up in my local Claude Code MCP list the other day, it seems inevitable that there will be skills integration across environments as well at some point.

  • simonw
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In working on Rodney I found out that the Claude Code for web environment has a Chrome browser installed already. It's a shame you can't see its output directly - even if it takes a screenshot there's no easy way to view it other than having it commit and push that to a branch in GitHub.
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This comment is regurgitating Simon's post with too much adherence to the input tokens. The unnatural, promotional restating of proper nouns in constrained output is a notable LLM tell.

Please respect the Hacker News community and read https://news.ycombinator.com/item?id=46747998.

  • yodon
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If you could actually detect AI content with high accuracy, you would sell it as a service and print money, but you can't, so you force all the rest of us to wade through posts like yours, claiming to tell the rest of us what is and isn't AI, which are FAR more annoying, disruptive, and low signal than the post you're commenting on, which is intelligent, adds to the conversation, and is, by my read, almost certainly actually human authored, just written by someone who knows how to write.
I'm not affiliated with it in any way, but you might want to check out the leading model https://arxiv.org/abs/2402.14873 and the mixed authorship detection https://www.pangram.com/blog/pangram-3-0-technical. LLM detection has come a long way since the first GPTZero.

Human heuristics - I've prompted millions of tokens across every frontier model iteration for all manner of writing styles and purposes - also helps greatly.

Concerning to me are long-time posters who (perhaps unknowingly) advance the decline of this human community by encouraging the people breaking HN guidelines. Perhaps spending a few hours on Moltbook might help develop such a heuristic, since "someone who knows how to write" is just a Claude model with a link to the blogpost.

https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...

Thanks for your comment!

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