Dev Frontend

Frontend Implementation

Overview

Implement the requested frontend behavior in the repository's existing stack. Reuse the nearest proven component, hook, service, style, and page structure by default; extend before creating, and create only when current owners cannot satisfy the task.

Consume urn:skills:frontend-change-request:v1 and produce urn:skills:source-change-result:v1. Typed Task, authority, graph, or package inputs are used when supplied; they do not replace current source and repository contracts.

Workflow

1. Read effective repository guidance, identify the real frontend root, package manager, runtime, target route/component, and current Worktree state.
2. Read only the authorities and source needed for the target slice. Start with the user requirement and current implementation; use Product/UI specs and the resolved <design-root>/DESIGN.md only when they apply. A missing optional artifact or graph does not create a prerequisite ceremony. Treat declared Product behavior readiness and UI visual/interaction readiness as independent axes: when both lanes apply, require both matching slice verdicts to be ready before editing. One Ready verdict never upgrades the other; route a conflict or blocker to its semantic owner rather than choosing between authorities.
3. Complete a bounded search for the current owner, analogous consumer, and reusable component before choosing an implementation owner. If the supplied context already identifies the same maintained file, owner, and function for this feature, use that record directly and verify the target in current source; do not call repo-map. Only when a cross-owner reuse or impact edge remains unresolved may an existing compatible repo-map snapshot serve one bounded navigation query. Never scan, refresh, or render a map for task-local implementation. Collect only the contract facts changed by, depended on by, or decisive to acceptance for the target slice. Load project grounding only when the change crosses a real API/auth, environment/build, durable-data, desktop/native, compatibility, deployment, or cross-repository boundary. Keep unrelated risk classes out of scope.
4. Use the reuse and page-ownership checklist to freeze one task-local contract revision before editing: observable acceptance, non-goals, affected owners/contracts, reuse decision, and smallest credible validation seam. For API-backed behavior, resolve every decisive field from the governing contract and current call chain; unchanged non-decisive fields inherit their current verified owner. Stop rather than infer an unresolved decisive field. A correction creates a new revision: reject delayed work for the old revision and reconcile any landed old hunks before implementation resumes. Keep route/tab shells declarative; independent stateful sections belong in feature components rather than a large conditional page.
5. Make the smallest coherent source change. Preserve established framework, routing, state/data, component, styling, and test owners; do not introduce a parallel stack or speculative shared layer. For legacy or native-wrapper frontends, first identify whether a directive selects a platform, build mode, or runtime environment. Never reinterpret platform guards such as uni-app APP-PLUS as development/production selection. When environment identity is branch-owned, preserve the target branch's manifest, endpoints, native plugins, signing settings, and vendor-channel values; do not add a parallel environment map, wrapper build script, or package-manager policy unless the accepted task changes that architecture.
6. Batch a coherent development slice before validating it. Treat a running dev server, compiler, type checker, or repository diagnostic stream as the first feedback loop; do not run a check after every edit while that signal remains clean. At slice completion, before handoff, or after a real error, run one nearest focused check. Expand only for a changed shared contract, generated/build chain, runtime boundary, or affected consumer, or when no narrower credible check exists. For a confirmation, keep, or no-op request, select the focused check for the current accepted baseline; do not run a post-change check that only applies after an authorized change. If that focused check fails, do not report completed: report the failure or Not verified, preserve its evidence, then diagnose or stop. Before an expensive run, use low-cost static and boundary checks that can expose deterministic blockers. A blocker stops only dependent acceptance runs; a warning does not. An already-authorized minimal diagnostic run may investigate the blocker, but cannot count as acceptance. Keep platform/path/process checks in the project verifier. When no narrower credible check exists, run the existing local build or suite once if it can verify the changed behavior; state its reason, command, and scope first. Preserve separate authorization for substantial extra cost, dependency installation, production access, and external effects. If no supported check can establish the claim, report that evidence gap; do not repeat unchanged checks.
7. Report changed owners, reuse decisions, validation, remaining Worktree content, and every applicable runtime or external gap as Not verified. The coordinator continues browser/client acceptance or Git delivery through its owner when already authorized by the request or effective instructions; source implementation grants no new authority.

Small Change Fast Path

Use this path for one known owner and a local style, template, icon, copy, or similarly bounded component change with no API, state/data, public/shared contract, generation, build, deployment, or production-behavior change.

1. Perform one targeted lookup and one minimal patch. Batch adjacent edits before one completion checkpoint; never validate after each edit.
2. If an already running dev/compiler diagnostic remains clean, finish with a local diff inspection and git diff --check. A new test run is optional and should occur only for changed observable behavior, an existing focused regression, a real dev error, or an explicit request. Report tests Not verified when they were not run.
3. Avoid aggregate tests or builds unless they are the only credible check under the workflow above. Do not add a red test for pure style/template/icon/copy changes.
4. End this implementation stage after the checkpoint. Continue already-authorized acceptance and delivery through their owners; do not add unrelated investigation, delegation, review, or repeated checks, or omit requested runtime acceptance.

Conditional Profiles

• Selected visual source: load authorities and visual evidence only when an accepted source and implementation-ready UI contract actually govern the task. Map applicable acceptance IDs before editing; use ops-browser or ops-client for required runtime evidence. Two-pass same-state comparison is a visual-completion gate, not a default requirement for ordinary frontend changes.
• Layout or affected interaction: load layout governance when geometry, overflow, scrolling, layering, breakpoints, state transitions, competing inputs, focus, or hit testing materially change.
• Maintained CSS/Sass/Less: load CSS governance when spacing ownership, cascade cleanup, flex/grid choice, or rendered wrapper structure materially changes.
• Project-owned UI governance: load UI components and tokens only when the change adds or modifies a shared UI component, direct third-party UI dependency, structured token source/generated output, Component Registry, or adoption record. Use the project's native validator and stop on stale or conflicting ownership; ordinary feature composition does not activate this profile.
• Protocol or generated client: load protocol contracts only for an existing or explicitly introduced contract chain.
• Behavior-first implementation: load behavior first when a stable public seam can support one red-capable check per behavior.
• Framework, styling, state, desktop, tooling, quality: load only the matching framework, styling, stack, or code-quality profile required by the current change.
• Forgeway integration: when an immutable Run and input PackageManifest are supplied, bind the changed result and observations to that basis. Do not require a Forgeway Run for normal repository development.

For a maintained non-LLM UI projection: Require a named owner, producer, non-LLM consumer, semantic version, executable validator, drift policy, and retirement rule. Run the repository-defined non-mutating validator before relying on it, then verify referenced routes and components in current source. Otherwise ignore the projection rather than creating or repairing one for ordinary implementation.

Hard Rules

• Follow repository-pinned versions, lockfiles, scripts, directories, and dependency policy; do not normalize unrelated tooling.
• Existing components, adapters, stores, utilities, tokens, and interaction patterns are the default. A new owner needs a targeted search and a concrete behavior or ownership reason.
• An API filename, legacy prose example, frontend wrapper default, or screenshot is not sufficient authority for method/path, parameter placement, trigger timing, or success semantics. Resolve decisive contract fields before implementation and keep unavailable runtime proof Not verified rather than compensating with fallback code.
• Keep page/tab shells responsible for navigation and composition, not section-specific APIs, forms, tables, drawers, validation, and lifecycle branches.
• Treat reveal state for masked sensitive values as an explicit interaction contract. For a list intended to show at most one value, opening a new row must atomically hide the previous row; validate both the newly opened row and the prior row after the same transition rather than checking only the clicked item.
• Prefer non-mutating validation. Compare Worktree state around tools that may generate or rewrite files and never absorb unexplained drift.
• A build, lint pass, source inspection, or browser preview proves only its own layer. Mark unexercised visual, responsive, accessibility, network, desktop, deployment, and production behavior Not verified.
• Stop on missing source-edit authorization, an unresolved governing contract, or a second failure of the same frozen runtime acceptance; preserve evidence and return to diagnosis instead of adding speculative patches.
• Do not stage, commit, push, deploy, or open a pull request from this Skill.

Output

Return capability frontend.source.implement with scope, project/stack, authority and reuse decisions, changed files/contracts, focused and expanded validation, Worktree drift, exclusions, and Not verified gaps. Include visual mapping and runtime passes only when the selected-source profile was active. Keep successful command output to a result summary; include relevant log tails only for failures.

References

• Core: usage, checklist, authorities, grounding, evals.
• Conditional: layout, CSS governance, UI components and tokens, visual direction, motion, visual evidence, visual example, protocols, OpenAPI governance, behavior first, codebase design, frameworks, styling, stack, quality.