Claudeagent and ClaudeagentA very long step log stays fast. Each chunk of a job's log is read once, into its step's log, as it arrives (`appendLog` in lib/log-lines.ts), where before every chunk joined the step's text again and read all of it from the start: a group a chunk leaves open holds the next chunk's lines, a line still being written shows until it ends, and a search reads the lines already read, once a change. A step of more than 2,000 rows draws only those on screen and 800 pixels either side (lib/log-window.ts), each row one line high until it is drawn and measured, so the space kept above and below is right however lines wrap; groups fold in the page's state rather than in a `details`, and search, following the newest line and Jump to latest work as on a short log. Each line's number links to it as GitHub's do (`#step:3:12`), opening its step and its group, scrolling to it and marking it. With a synthetic 50,000-line log in 500 chunks of 100 lines, reading it took 24.6 s in all and 105 ms for the last chunk before, and 0.5 s and 1.3 ms now; in Chromium the page drew the whole log in 2.2 s and each new chunk in 213 ms (157,000 elements), and now in 51 ms and 17 ms (385 elements). The Actions guide says so.062ffb4History