Reopening a session downloaded the conversation again, every time, over
the tunnel. It now draws from a copy of what the server has already sent
and asks for one event to check that copy is still current.
Per session, under cacheDir, the server's own event lines in chunks named
for the range they cover -- so a coalesced page, whose lines do not say
what they cover, still records it. Only the contiguous run ending at the
newest chunk is served; a gap is closed by paging through it, bounded by
`after` on /transcript so the page stops where the phone's copy starts
and can therefore be kept. Nothing is derived and stored: rows are a
rendering, and a cache of them would need throwing away on every change
to the fold.
Nothing here is load-bearing. Missing, evicted, damaged or unwritable all
degrade to the cold open this screen did before, and the check before the
stream resumes -- one request, one event -- is what stops a replaced or
truncated file being spliced onto a copy of a different conversation.
What that check cannot see, a line changed mid-file with the tail intact,
is what Reload in session settings is for.
Measured on the emulator against ui-sandbox, on a 505-event session:
reopening it costs one request for one event, including scrolling the
whole conversation back; a cold open is two requests and 100 events. A
reset after falling 300 behind fetched the gap as four coalesced rows
rather than re-fetching 104 events and discarding them. Every chunk was
checked line by line against what the server says for the range its name
claims, across the reset and the gap-fill.
transcript-bench.sh, same viewport content and gestures, before and
after: p50 16.9ms both, p90 25.6 -> 23.2ms, p99 33.5 -> 36.7ms, and the
transcript's own draw accounting 0.33ms -> 0.32ms with place 0.31ms
either way. Within the emulator's noise, which is what a cache must be:
it changes what is fetched, not what is drawn.
Building it also found that the server handed out the same transcript
line two different ways. serde_json's default float parser is not
correctly rounded, so a ts written as ...0757 came back from /transcript
as ...0755 while the SSE stream sent the original -- invisible on screen,
since a ts is drawn as a relative time, and visible here only because the
cache compares a line it holds against the server's answer. Fixed with
float_roundtrip, with a test that fails the moment it is dropped.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
`POST /sessions/{id}/cwd`, behind a field in the session settings dialog. A
working directory is settled when the process is spawned -- the CLI is
launched with it as its cwd and there is no control request that changes one
-- so this records the new one and ends the process that is in the old one.
It does not start a replacement, and the field says so in a line beside it:
a session with no process starts on the next message or on Start, which is
this app's rule for that everywhere else, and "usually restarts" is a worse
control than "always stops".
The path is checked against the session's own machine and refused if it is
not there. The spawn path corrects instead of refusing, because it is
resuming a directory the *machine* recorded and that can be gone through
nobody's fault; a path somebody has just typed is different, and a mistyped
one accepted here would surface much later as a session that would not
start, with nothing pointing at the typo. The refusal names the machine and
the path, and is drawn under the field it is about.
Nothing of Claude Code's own is moved, and that is measured rather than
assumed: on CLI 2.1.237, `claude --resume <id>` finds a session from any
working directory -- an id that does not exist answers "No conversation
found with session ID", and a real one resumed from an unrelated directory
did not. So the conversation continues in the new place with nothing
relocated. Doing otherwise would mean reproducing a rule this app cannot
see the whole of; PLAN.md records what that rule is, for whoever tries.
Found while checking it: `SessionInfo.cwd` came from the snapshot a session
launched with, so a moved session went on reporting its *old* directory for
as long as its process lived -- a dialog showing a directory the next launch
would not use, with nothing saying so. It is read from the config where the
row is built now, the same way `setup_name` already was, and for the reason
already written above `setup_name`: only the manager holds the config, and
both of these change under a running session.
Checked end to end on the emulator against a session whose process really
does take a cwd: /proc said /tmp/cwd-a before and /tmp/cwd-b after, the
dialog showed the new path immediately rather than after a restart, and a
directory that is not there and a relative path were both refused with the
session left exactly as it was.
A Rust backend that owns the sessions and an Android app that reads them.
The server spawns and adopts CLI processes, normalises everything they emit
into one event model, keeps the transcript, and serves it over pinned TLS on
a WireGuard interface; the phone streams that, replies, sends images, and
imports conversations the machine already has.
`AGENTS.md` is the working guide -- what runs where, what has been measured,
and the faults that were expensive to find. `PLAN.md` is the design record.
History before this point was squashed away. It was a personal project's
running commentary and carried a name and a couple of machine paths that
have no business in a public repository; the tree is what mattered and the
tree is here.
irisandClaude Opus 5