Field notes · No. 016
Senior DevOps Engineer building in public. Shipped features across Local Fitness, Ghostwriter, and more — the tradeoffs behind them, and what broke.
Three releases of my LinkedIn ghostwriter went to interaction cost: one dialog instead of a chain of questions, silent setup instead of narrated bookkeeping, and generated visuals grounded in real command output after an invented one cost nine review rounds.
Every card my LinkedIn ghostwriter generated had the same skeleton, because a template plus an LLM equals the same output forever. The fix was a component vocabulary, a card-history file, and a rule that each new card must differ from the last three on at least two axes.
How to measure a rendered HTML page for overflow and truncation before a human ever sees it, and the CSS trick that lets one layout adapt itself to however much content lands in it.
Ghostwriter's voice profile and credentials lived inside its own repo, so a dev checkout and a marketplace-installed copy each needed their own setup. Moving personal config to the home directory collapses that back to one source of truth.
Ghostwriter moved from a manual symlink install to a real Claude Code plugin, which meant learning the marketplace.json/plugin.json schema and one directory-nesting rule that Claude Desktop enforces and the CLI quietly didn't.
A rendered card and its stylesheet are two files that only agree by convention, nothing in HTML or CSS enforces it. Here's how to write a fast, deterministic test that catches the drift before a render silently ships unstyled.
Ghostwriter's post images moved from a dark look to a light one by changing a single CSS class. Here's how to build a token-driven theme switch, render it to a deterministic PNG, and catch the one missing token that makes text disappear.
An agent that writes a confident claim will just as confidently skip checking it. Version 0.7.0 adds a code gate that blocks publishing until every outside-world claim traces to real, live sources, and it has to survive garbage input and a harness that lies about testing it.
Claude Code's own docs say its session transcripts are an internal format that can change on any release, yet discovering what you shipped recently has no sanctioned API. Here is how to read the logs anyway, defensively enough to survive the warning.
Ghostwriter's new matrix card type shipped as one new file, with no registry code touched. Here's how a naming convention can stand in for a plugin registry, and the test that keeps it from shipping half-wired or quietly duplicated.
Ghostwriter's image cards got pulled onto one shared base and grew a portrait carousel with a progress bar. The mechanism behind it, CSS custom properties feeding a headless-browser render pipeline, is a pattern you can reuse for any HTML-to-image or HTML-to-PDF generator.
ghostwriter v0.3.0 added carousel support: a headless-browser render step that turns HTML slides into a single PDF, and a publisher path that uploads it through a document API LinkedIn renders as a swipeable carousel. Here's the render-and-ship pipeline, built generic enough for any chunked document upload.
Ghostwriter's 0.1.0 release added one new card type: three ascending bars for an accelerating progression, with the bar heights fixed for effect rather than computed from the numbers next to them. Building it is a clean example of a small, reusable system: a CSS brand guide, a headless-browser render step, and a verification step that checks the honesty claim is actually true.
The ghostwriter skill's first versioned release made a markdown instruction file gradeable by CI and pushed its automation scripts to 100% line coverage. The two techniques worth stealing: a pass/fail scorer over frontmatter and body text, and monkeypatching a dependency your code doesn't even import until the function runs.
Ghostwriter can now attach a locally rendered diagram or card to a post, and the two techniques worth taking are waiting on a real completion signal instead of network idleness, and keeping personal styling in a gitignored file a stranger's clone never has to see.
