Components: Generate Tablist

[JasonVMo]

Summary

Generate Tablist with its canonical contract, implementation, tests, stories, platform validation, and explicit package export so tabs have a consistent navigation container. Tab already exists, but the required roving keyboard focus remains gated on the shared FocusZone decision.

Observed. tablist is entry tablist in the canonical catalog and has no
implementation in packages/agentic/components. Upstream describes it as: Horizontal container grouping Tab components into a navigation strip for switching between content views, with gap spacing, roving tabindex, and an optional end-content action slot. Layout-only: it delegates all visual styling to its Tab children.

Goal

Generate the tablist component in
packages/agentic/components/src/components against the
canonical Fluent Flex spec, with the colocated coverage, stories, and platform
validation the package requires, and export it explicitly from
src/index.ts.

Stage

Stage 3 (production). Wave 3 - focus-orchestrated and composed.

Why it matters

Observed. The canonical catalog has 50 components and the agentic library has
generated 18. tablist is one of the 32 in the gap, enumerated in
the missing-components index.

Inferred. It is a composed or focus-orchestrated component whose blockers resolve once the wave 2 overlay stack and the focus decision land, so it is a direct measure of whether those foundations were built correctly.

Observed current state

Canonical spec and source

Field	Value
Canonical spec	plugins/components/skills/tablist/SKILL.md with usage.md, web/tokens.yaml, web/accessibility.md, and web/interaction.md, at x3-design/fluent-design @ d334acf
Upstream tier	molecule
Upstream catalog key	tablist in component-map.yaml
Local staged spec	packages/agentic/components/specs/tablist - SPEC.md, usage.md, interaction.md, accessibility.md, tokens.yaml, blockers.md
Local implementation	None. No src/components/tablist directory exists

Closest existing FURN or V1 implementation

• packages/components/TabList - TabList/, Tab/, and TabListAnimatedIndicator/. TabList.tsx renders FocusZone for keyboard navigation. There are no platform-specific implementation files, so this is the cross-platform and desktop reference.

Note on platform canon. Where a legacy package has platform-specific files, the
desktop path (.win32, .windows, .macos, or the unsuffixed cross-platform file)
is the compatibility reference. .ios, .android, and .mobile variants are not
treated as the cross-platform canonical implementation.

Local dependencies

• src/components/tab - Observed present (component).
• src/components/button - Observed present (component).
• src/components/divider - Observed present (component).

Known blockers

Observed (blockers.md, blocker class A in the index).

Three blockers were recorded: the spec depends on a Tab child for selection and roving-tabindex behavior; "this package currently has no src/components/tab or src/primitives/tab implementation to compose against"; and the session could not add Tab alongside Tablist.

Reassessment.

Stale. src/components/tab now exists with 10 runtime cases, a type test, and a story, and it treats selected as externally driven, which is exactly the model Tablist needs. Inferred: only the roving-focus model remains, from focus-zone.md.

Scope

• Ingest or promote the spec into the component directory in the generated shape
  (SPEC.md plus a spec/ folder), per
  spec-ingestion-and-generation.md.
• Establish the public contract first: variants, slots, native props, accessibility,
  interaction states, and platform behavior.
• Implement the required file structure from
  src/components/AGENTS.md:
  tablist.types.ts, tablist.styles.ts, use*.ts, use*Styles.ts, render*.tsx, and
  the assembly module with a displayName.
• Style from Flex tokens first and record genuine token gaps rather than substituting
  unrelated values.
• Export the component, its public types, and the state, style, and render stages
  explicitly from src/index.ts under component-qualified unstable names.
• Keep Tablist layout-only, per upstream: gap spacing, arrangement, keyboard navigation, and the optional end-content slot, with no fills, strokes, or typography of its own.
• Own selection at the Tablist and let Tab report presses, matching the existing tab contract.
• Implement roving tabindex per the outcome of focus-zone.md.

Out of scope

• Changing the contract of an existing generated component, unless this task explicitly
  calls for it above; raise it as its own item.
• Building shared infrastructure owned by another task: overlay hosting
  (popover), roving focus (focus-zone.md), spec
  ingestion (spec-ingestion-and-generation.md),
  or the coverage contract (component-test-strategy.md).
• Migrating any legacy FURN consumer onto this component.
• Mobile platform support; the applicable upstream companion is web, retargeted to
  React Native for Windows and macOS.

Deliverables

• src/components/tablist/ implementing the full required file structure.
• SPEC.md and a spec/ companion folder with provenance recording the upstream path,
  SHA, and ingestion date.
• Colocated tablist.test.tsx, tablist.types.test.ts, and tablist.stories.tsx.
• Snapshot coverage where the visual contract is state-dependent, or a recorded
  exemption.
• Explicit exports from src/index.ts, with src/index.test.ts updated.
• A changeset, per the repository's version management rules.
• A recorded readiness level with its supporting evidence.

Required coverage, stories, and platform validation

Runtime and type coverage:

• Every gap-spacing value tied to size.
• End-content slot present and absent.
• Arrow-key navigation with wrap, plus Home and End.
• Only the selected tab is in the tab order.
• Tablist and tab roles, and the selected relationship.
• That Tablist applies no visual styling of its own.
• User style and handler forwarding, and that user styles are applied after component
  styles.
• Compile-time slot acceptance and any mutually exclusive props.

Stories: a typed Meta titled Components/Tablist, an args-driven Default, a
grouped Overview when the contract has several axes, one focused story per variant
axis, and an interactive story for each stateful axis. Self-driving axes expose
default<State> as the control; externally driven selection is owned by the story with
React.useState. Identity-changing axes are not exposed as controls.

Platform validation: the component's stories render and behave correctly on macOS
and on React Native Windows Fabric through apps/storybook,
including hover, pressed, disabled, focus, optional-slot, and constrained-content
scenarios. Add a stable root testID if the component joins the automated smoke set.

Acceptance criteria

• src/components/tablist exists with the required file structure and a displayName.
• Every variant axis in the component's SPEC.md is implemented, or a deviation is recorded in the spec.
• The component styles from Flex tokens, with any genuine token gap recorded rather than approximated.
• Focus feedback renders through FocusVisual; no outline* props and no React Native Windows native focus visuals are introduced.
• State precedence is explicit: disabled wins over pressed, which wins over hovered.
• Every stateful axis is classified as self-driving or externally driven, and both paths are covered.
• Runtime, type, and story coverage satisfy the package coverage contract.
• The component, its public types, and its pipeline stages are exported explicitly from src/index.ts, and src/index.test.ts covers them.
• The component's stories render on macOS and on React Native Windows Fabric.
• yarn workspace @fluentui-react-native/components format, lint, build, and test pass, and the Storybook bundle succeeds for both desktop platforms.
• A readiness level is recorded with its supporting evidence.
• A changeset is included.

Dependencies and ordering

• Blocked by wave 2, either directly or through a wave 2 dependency listed above.
• Gated by component-test-strategy.md: the component must satisfy the coverage contract on arrival rather than being retrofitted.
• Gated by readiness-model.md: the target readiness level must be stated before the work starts.
• Consumes the Infrastructure workstream (storybook-e2e.md) for automated macOS and Windows Fabric validation; until it lands, platform validation is manual.

Risks and open decisions

1. Upstream also carries a mobile spec for Tablist; the desktop web companion is the applicable source per the inclusion rules.
2. Whether activation follows focus or requires an explicit press differs by platform convention and must be stated.

Evidence and references

• Upstream spec: plugins/components/skills/tablist/SKILL.md and
  components-index/SKILL.md
  at x3-design/fluent-design @ d334acf.
• Local staged spec and blocker record: packages/agentic/components/specs/tablist.
• Canonical implementations to follow: src/components/button
  for a styled higher-order component and src/primitives/icon
  for a primitive.
• Authoring rules: src/components/AGENTS.md and the
  agentic component authoring skill.
• Workstream context: Components README and
  the missing-components index.

Sources retrieved 2026-08-20.

[JasonVMo]

TabList shipped in PR #4296, so I am closing this issue as completed.