# SIDEBAR.md — the session card contract

One rule for how a session is rendered as a card in the sidebar, so the web
sidebar (#107) and the TUI sidebar (#108) describe a session the same way.
Read this before changing either. Both clients implement exactly what is
written here; if it needs to change, change it here first.

A card is always two lines: **line 1** and **line 2**.

## Line 1 — name + actions

- Left: the session name — `metadata.name` if present, else the command line
  (same fallback both clients already use).
- Right: two actions anchored to the top-right corner: **spawn similar**
  (`⧉`) and **kill** (`✕`). In the TUI these are keyboard affordances shown on
  the highlighted row; in the web they are buttons. The glyphs are shared so
  muscle memory transfers.
- Actions reserve their fixed width; the name truncates with `…` before it can
  ever reach them. **Overlap between the name and the actions is a defect** —
  that overlap is what started this milestone.

Line 1 carries no badges. The `⚠ blocked work` badge (#83) and the `exited`
badge move off this row into line 2.

## Line 2 — meta line (adaptive)

Line 2 always renders — never an empty placeholder row either, since its
unconditional fragments (see below) always have something to show. Its
*fragments* are adaptive: some show only when their trigger holds. The line
itself is not.

Line 2 reads left to right:

```
<dot> [<duration>] [<detail>] [<blocked work> | exited] <command>
```

Its minimum content is therefore the dot and the command.

`<dot>` is a single filled glyph (`●` on both clients) carrying the activity
state's colour, and `<duration>` follows in the same colour when shown. There
is no state word and no second badge: the dot exists so the state is still
legible when a row is dimmed or the terminal renders the duration in the
default fg. The dot is an unconditional part of line 2; the bracketed
fragments appear only when their trigger holds.

`<duration>` renders only once the session has been held in its current
activity state longer than **30 seconds** (`activity_since` from #102) — under
that threshold the duration is absent and the dot renders alone. A payload
that predates #102 (no usable `activity_since`) likewise contributes no
duration — the dot still renders. This rule now governs only the duration
fragment; it no longer decides whether line 2 exists.

`<detail>` is an agent-reported string (#105) — e.g. why a session is in
`Error`. It sits right after the duration, in the muted style, and shows only
while an agent-reported state is in force (see Precedence): when the report
lapses at its TTL or is replaced, the detail goes with it. The detail
truncates with `…` ahead of the trailing fragments — a long detail never
pushes `<blocked work>`, `exited`, or `<command>` off the line, and neither
client ever lets it wrap.

`<command>` is unconditional and muted: the session's command line, shown on
every card in both clients — no omission in the TUI, no name-vs-command
comparison gating it. A session named by its command line then shows the same
string on both lines; that is accepted, the price of a row that never changes
height.

## Colour per activity state

The state word is never spelled out — the colour carries it.

| Activity state   | Web token | ratatui colour    |
| ---------------- | --------- | ----------------- |
| `Active`         | `--live`  | `Color::Green`    |
| `Idle`           | `--muted` | `Color::DarkGray` |
| `AwaitingInput`  | `--warn`  | `Color::Yellow`   |
| `Error`          | `--danger`| `Color::Red`      |

Web tokens resolve per theme automatically (`styles.css` defines dark, light,
and `prefers-color-scheme` variants for each). The TUI uses the plain ratatui
named colours above; do not introduce RGB values or a new palette module for
this.

The duration text inherits its state's colour; the blocked-work, exited and
command fragments use the muted colour (`--faint` / default style), since the
⚠ glyph already signals severity.

## Duration format

Time spent in the **current activity state**, sourced from `activity_since`
(#102) — *not* time since spawn, and *not* time since last PTY output
(`last_activity_at`). Both clients compute it identically:

- `< 60s` → whole seconds, floored: `30s`
- `< 60m` → whole minutes, floored: `4m`
- `≥ 60m` → whole hours, floored: `2h`

No days unit, no seconds inside minutes, no rounding up. Floor everywhere so
the counter never shows a duration the state hasn't actually reached yet.
Clock granularity: re-render at least once every 30s while visible so the
cutover points land within one tick.

## Precedence

An agent-reported `ActivityState` (#105) overrides the daemon's inference for
**five minutes** (the TTL is fixed by the daemon; re-reporting extends it).
When the TTL expires, inference resumes and the session's reported detail —
if any — clears with the report. Clients never blend the two: whichever source
is in force supplies both the colour and the clock for `activity_since`.

Two rulings specific to a reported `Error` (#114):

- **The five-minute TTL applies to `Error` like to any other state.** A
  session that failed is still failed after five minutes, but a card pinned
  red forever lies once the session moves on; when the report lapses the card
  returns to the daemon's own inference — usually `Idle` for a session that
  has gone quiet.
- **Only a new report clears an `Error` before its TTL.** The next
  `ActivityState` of any kind replaces it (with #106's hook that is typically
  `PreToolUse` → `Active` when the user prompts again). PTY output and
  process changes do not clear it — only the agent itself may withdraw what
  the agent itself reported. Re-reporting `Error` extends the TTL rather than
  stacking reports.

If a client receives an `ActivityState` variant it does not know, it must not
fail rendering: treat it as `Idle` (neutral/dim, line-2 rules apply as usual)
until the daemon sends a variant it does know. Rust clients deserialize
activity leniently for the same reason.

Leniency runs one way only. It covers a client *reading* a newer daemon, where
dropping the whole session would be worse than dimming one card. A report
arriving at `POST /api/sessions/:id/activity` is parsed strictly and an unknown
state is a 4xx: an agent posting a state the daemon does not know is a bug in
the agent, and answering 204 would hide it.