Coding guidance go tui

Go TUI Coding Guidance

Portable implementation, refactoring, testing, and review guidance for interactive Go terminal user interfaces built with Charmbracelet Bubble Tea, Bubbles, Lip Gloss, embedded Huh forms, and related Charm libraries.

Adjacent Skills

Use this as the default principle skill for Charmbracelet Go TUI work. Compose with:

• Workflow: thinking for planning, recursive-thinking for stress-testing, tester-mindset for validation strategy, and security for sensitive input, shell execution, token display, or filesystem access
• Project overlays: project-core-dev for repo validation, project-config-and-tests for config and deterministic tests, and project-platform-diagnose for terminal capability, piped stdio, SSH, alt-screen, shell, platform, install, or runtime smoke issues
• Go depth: coding-guidance-go only when the non-TUI Go package design, concurrency, service boundary, profiling, or module behavior is the main risk

Use coding-guidance-go instead when the task is a non-interactive Go CLI, library, worker, service, or test change with no terminal UI state machine.

Reference Map

Load references only when the task needs that depth:

• references/charmbracelet-patterns.md for version-specific Bubble Tea APIs, Bubbles component integration, Huh form integration, Lip Gloss APIs, key binding patterns, and upstream example routing
• references/tui-layout-and-production.md for layout arithmetic, responsive panels, mouse hit testing, screen/focus state machines, production polish, performance, noninteractive fallbacks, and Bubble Tea code-review false positives

When Not to Lean on This Skill

• non-Go terminal UI frameworks such as ncurses, Textual, blessed, termbox, or curses-style wrappers unless only the generic TUI UX ideas apply
• simple command-line flag parsing, one-shot command output, or prompt-only flows that do not maintain an interactive screen
• shell-only prompt polish with Gum, VHS, Mods, or plain shell unless the user is explicitly converting the flow into a Go Bubble Tea TUI
• web, mobile, or graphical desktop UI work; use the appropriate UI or platform guidance instead
• broad Go backend, package architecture, or performance work where Bubble Tea, Bubbles, and Lip Gloss are incidental

Implementation Workflow

1. Inspect go.mod, imports, nearby models, Bubbles and Huh components, Lip Gloss styles, examples, tests, and docs before editing. Preserve the repo's current Charmbracelet major version and import path unless the task is explicitly an upgrade. Check upstream Charm examples when the component pattern is unfamiliar.
2. Identify the app mode: inline or full-screen, alternate screen or normal output, keyboard and mouse expectations, input/output streams, width and height constraints, external commands, background work, noninteractive or --no-tui fallback, and error states.
3. Model the TUI as an explicit state machine: screen or mode, focus target, previous screen or return path, dimensions, data loading state, request or stale-result marker, domain state, selected item, cursor or scroll position, pending command, error/status message, and child component state.
4. Keep Update deterministic and fast. Represent side effects as tea.Cmd values that return typed tea.Msg values; do not block on filesystem, network, subprocess, timers, or heavy rendering work inside Update or View. Use tea.Batch for independent commands and tea.Sequence only when ordering is observable behavior.
5. Compose Bubbles and Huh components deliberately. Store component models in the parent model, route key and resize messages by focus or mode, assign updated component values back to the parent, collect returned commands, and keep child widths, heights, styles, and focus state synchronized.
6. Render from state only. View should not mutate state, start work, read files, call services, log, or depend on wall-clock time. Build terminal layouts with Lip Gloss styles, cell-aware helpers, strings.Builder, and caches for expensive derived text instead of ad hoc ANSI string arithmetic.
7. Design terminal UX as product behavior: clear focus, visible help, safe quit and cancel paths, loading and empty states, recoverable errors, accessible keyboard shortcuts, resize behavior, narrow-terminal fallbacks, plain-output escape hatches, and no mouse-only interactions.
8. Add or update focused tests close to the changed behavior. Prefer model transition tests with synthetic messages, command tests around command constructors, and stable render assertions for important layout or text contracts.
9. Run the narrowest relevant formatter, import formatter, tests, and manual smoke command the repo supports. A visible TUI behavior change usually needs at least one interactive smoke run or recorded terminal-output check.

Refactoring Workflow

Use this instead of the default implementation workflow when the task is primarily cleanup or restructuring:

1. Capture current states, messages, commands, key bindings, component ownership, render paths, dimensions, and external side effects.
2. Add characterization tests first when state transitions or command behavior are unclear.
3. Split tangled root models into screen, component, command, and style helpers only when the split makes state ownership and message flow easier to follow.
4. Preserve user-visible key bindings, output text, persisted formats, command side effects, and terminal mode choices unless the task explicitly changes them.
5. Keep the app runnable after each slice; terminal apps are easy to break with a compile-passing render or focus regression.

Review Workflow

When reviewing, skip implementation steps and use this checklist:

1. Read the full state/message/render loop before commenting.
2. Identify findings, ordered by severity: Critical > Important > Suggestion.
3. Rank correctness, data-loss, terminal-state, and event-loop defects above polish. Layout, color, and help-text issues become higher severity only when they block navigation, hide required information, or break supported terminal contexts.
4. Prioritize blocking Update or View work, lost or unordered commands, unhandled errors, command goroutine leaks, state mutation during rendering, stale window dimensions, unassigned Bubbles component updates, key binding conflicts, focus traps, missing quit/cancel behavior, alt-screen cleanup hazards, and fragile string-width math.
5. Avoid false positives: helper functions returning tea.Cmd, value receivers on Update, nested child Update calls, and tea.Batch are normal Bubble Tea patterns when no side effect runs before the command is returned.
6. Check whether rendering handles narrow terminals, Unicode width, color profiles, no-color environments, redirected input/output, and noninteractive CI execution where the repo claims support.
7. State findings with the triggering message or interaction path, the expected state transition, and the likely user-visible consequence.

Bubble Tea Rules

• Treat the Bubble Tea model as the source of truth for UI state. Domain logic can live outside the model, but UI state should not be hidden in package globals or background goroutines.
• Use typed messages for domain results, errors, timers, subprocess completion, and external events. Avoid stringly message channels.
• Return commands explicitly. Use batching for independent follow-up commands and sequencing when ordering is part of behavior.
• Keep command constructors small and testable. They should capture immutable inputs, do the side effect, and return a typed success or failure message.
• Handle window-size messages at the top level, then propagate computed widths and heights to child components.
• Keep quit behavior deliberate. q, esc, ctrl+c, and form-cancel keys should match the app's conventions and should not discard work silently.
• Use program options such as custom input/output, context, fixed window size, or renderer disabling only when they match the repo's runtime or test seam.
• Keep logs and debug output out of the rendered screen. Route debug logging to files or test-only writers when needed.
• For current v2 code, keep terminal features declarative on tea.View; for older v1 code, preserve the repo's existing command-based terminal mode conventions unless the task is an upgrade.

Bubbles Rules

• Prefer Bubbles components for standard text input, text area, table, progress, paginator, viewport, list, file picker, timer, stopwatch, help, spinner, and key binding behavior before hand-rolling those widgets. Prefer Huh for multi-field forms when the repo already uses it or the form semantics are clearer than custom widgets.
• Store every child component's returned model after Update; losing that value loses cursor position, scroll state, validation errors, and internal timers.
• Route global keys before focused component keys only when global behavior must win. Otherwise let focused inputs consume editing keys.
• Use bubbles/key bindings and the help component for discoverable shortcuts when the screen has more than trivial navigation.
• Do not call blocking form APIs such as Run() from inside a Bubble Tea Update; embed forms through their Init, Update, and View loop.
• Do not copy a component example wholesale into production code without reconciling focus rules, width/height updates, styles, validation, and domain state ownership.

Lip Gloss Rules

• Centralize reusable styles, spacing, border, and color decisions. Avoid scattering raw ANSI escape codes or one-off magic strings across View.
• Measure rendered content with ANSI-aware, cell-aware helpers. Do not use len for terminal layout width.
• Treat width and height as inputs to rendering. Clamp panes, wrap long text, truncate low-value metadata, and provide compact fallbacks for small terminals.
• Account for borders, padding, and margins before rendering panels. Use frame-size helpers and explicit truncation or wrapping so bordered panels do not grow unexpectedly.
• Use proportional weights for split panes and match mouse hit testing to the current layout orientation: X coordinates for side-by-side panes, Y coordinates for stacked panes.
• Keep color optional and semantic. Preserve readable contrast, respect no-color or limited-color environments where the repo supports them, and do not encode state only through color.
• Build styles as values and render strings at the edge. Do not use style mutation or package-level mutable styles to smuggle runtime state into views.

Production Runtime Rules

• Detect noninteractive contexts the repo claims to support: piped stdout, non-terminal stdin, CI, TERM=dumb, NO_COLOR, and app-specific --no-tui or NO_TUI flags. Fall back to plain output rather than forcing a full TUI.
• Keep expensive rendering off the hot path. Precompute stable styles, cache markdown or syntax-highlighted text by content and width, virtualize large lists, and discard stale async results with request IDs, content hashes, or version counters.
• Make multi-screen apps navigable: explicit screen or route values, breadcrumbs or titles, focus restoration after modals, reset cursor and scroll state intentionally on transitions, and show the current sort/filter or mode in status text.

Validation

A Charmbracelet TUI change is done when:

• Go files are formatted with the repo's formatter and import tool
• touched packages compile and affected tests pass
• model transitions are tested with representative key, resize, success, error, quit, and cancel messages
• Bubbles component updates are covered where focus, validation, cursor, viewport, pagination, or timers changed
• important render output is checked at narrow and normal widths, with stable snapshots or focused string assertions when practical
• interactive behavior has been smoke-tested when terminal modes, keyboard input, alt screen, subprocess execution, mouse handling, clipboard, or cursor behavior changed
• noninteractive fallback is checked when the command can run in pipes, CI, or scripts, and narrow-terminal behavior is checked around an 80x24 baseline
• color behavior is checked for both light/dark assumptions and NO_COLOR or limited-color terminals when the repo supports them
• go test -race or equivalent concurrency validation runs when commands, goroutines, timers, subprocesses, or shared state changed

Examples

• Build a Bubble Tea TUI with a list, details pane, and help bar
• Review this Bubble Tea model for command ordering and focus bugs
• Refactor these Bubbles text inputs into a multi-step form
• Fix this Lip Gloss layout so it survives narrow terminals and Unicode text