claude-statusline: Instructions file for Claude Code

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

What this repo is

A custom statusline for Claude Code: a one-shot Bash script that reads session JSON from stdin and renders an eight-line colored status display. No build, no package manager, no test suite.

Architecture

See SPEC.md for the authoritative spec — output layout, color formulas, JSON input contract, IPC invariants, install wiring.

Two scripts:

• statusline.sh — the renderer
• hooks/compact-monitor.sh — a PreCompact hook that bumps a counter the renderer consumes via /tmp/claude-compacts-<sanitized_session_id>.json

Conventions to preserve

• Every jq lookup in statusline.sh must have a // default. Claude Code may add or rename schema fields; the script must degrade gracefully.
• Optional payload fields render gated. Fields that may be absent (pr.*, worktree.*, thinking.enabled, context_window.context_window_size, cost.total_api_duration_ms, version) are shown only when present / non-zero, so a line never emits a stray separator or placeholder. Keep new field additions gated the same way. See SPEC.md → Gated fields.
• Effort comes from stdin .effort.level, with no silent fallback. It is one of low/medium/high/xhigh/max (Claude Code normalizes ultracode → xhigh upstream, so it never arrives literally). A missing field (models without effort support, e.g. Haiku 4.5) renders as a dim —; a present-but-unrecognized value renders as a loud bright-red unknown so schema drift stays visible. Don't reintroduce a quiet default. See SPEC.md → Effort level.
• Cross-platform date: use the BSD-or-GNU fallback date -r "$EPOCH" "+%H:%M" 2>/dev/null || date -d "@$EPOCH" "+%H:%M" 2>/dev/null. Keep it when adding new time displays.
• Bars are built by glyph concatenation, not tr. tr ' ' '█' maps bytes, so GNU coreutils corrupts the 3-byte bar glyphs into invalid UTF-8 (only BSD tr rendered them) — the bars looked fine on macOS but were broken on Linux. Build runs with the repeat_glyph helper in statusline.sh (and the inline loop in docs/swatches.sh); mirror that for any new bar.
• Session id sanitization (tr -dc 'a-zA-Z0-9' | cut -c1-24) is the IPC key shared by statusline.sh, hooks/compact-monitor.sh, and hooks/account-monitor.sh. Change one, change all three.
• The account label must be derived from the session's own credential, never from ~/.claude.json. .oauthAccount there is a single machine-global slot shared by every Claude Code surface and is only rewritten by a full profile fetch gated behind a 24h TTL, so it can name a different account than the one actually spending quota (it did, for two days, before 2026-08-24). hooks/account-monitor.sh resolves the credential the session authenticates with and publishes the owner; the renderer reads only that. If resolution fails the label is a loud yellow ? — never fall back to a name that might be wrong. See SPEC.md → Account attribution.
• The context bar must not be wrapped in DIM — it uses 24-bit truecolor and DIM collapses the gradient. (The 5h / 7d limit bars are also truecolor but are intentionally wrapped in DIM for a softer look — that's a deliberate aesthetic choice, not a precedent to copy.)
• Bar widths: context 30 chars, 5h/7d 20 chars. If you change one, update its pct * N / 100 calculation too.
• Line width budget ≤ 60 columns. Keep every rendered line within ~60 visible columns (excluding ANSI codes and the line-8 ⚠ <drift> suffix appended by claude-backup). The shared label column is dynamic (it widens to the account displayName), so a long account name — or long repo/branch/PR/worktree on line 1 — can blow the budget. If a design change would push any line past 60, confirm the design with the user before shipping rather than silently overflowing. See SPEC.md → Width budget.
• docs/swatches.sh mirrors the colors. It regenerates the three README graphics and duplicates statusline.sh's palette + gradient formulas (it is not sourced by the renderer — that stays a single drop-in file). Change a color constant or gradient formula in statusline.sh → update docs/swatches.sh too, then re-render and re-screenshot the affected docs/*.png.
• docs/preview.sh regenerates the README text previews. It rewrites the two blocks between the <!-- preview:baseline --> / <!-- preview:full --> markers in README.md by running the real statusline.sh against fixed sandboxed payloads (pinned clock via TZ=UTC + a date shim, scratch git repos for branch/diff, fake HOME for the drift flag, seeded /tmp account + compact files). Unlike swatches.sh it does not duplicate renderer logic — it invokes statusline.sh, so it can only drift in its sample inputs, never in output formatting. It is deterministic (a no-op change yields no diff) and byte-reproducible across BSD/GNU (verified in a Linux container). After any change to statusline.sh's output, re-run it (./docs/preview.sh) and commit; no manual paste/screenshot needed (that's only swatches, because those are images). ./docs/preview.sh --check regenerates into a temp file and diffs without mutating README (exit 1 on drift); CI runs exactly this via .github/workflows/preview-check.yml, so a stale preview fails the build.