# Agent development workflow Common startup rules live in [AGENTS.md](../../AGENTS.md). This document holds procedures and conventions to read when they apply, not extra startup imports. ## Maintaining canonical knowledge After meaningful changes, assess documentation before declaring completion. Meaningful changes include user-visible behavior, architecture/data flow, maintenance/setup/debugging workflows, and subsystem contracts. Formatting, behavior-preserving refactors and isolated test changes need no doc update. Prefer the existing authoritative architecture doc or nearest module README; README.md owns top-level user/developer entry points. Update stale routes, paths, commands and contracts you encounter, or explicitly flag unresolved claims in the final summary. Repo docs remain canonical regardless of authorship. Keep AGENTS.md limited to repository-wide constraints and task routing. Do not add feature histories, method lists, schema inventories or troubleshooting procedures to it. CLAUDE.md imports AGENTS.md; do not mirror common prose by hand. Use [the context map](../maintenance/agent-context-map.md) for the owning document and relevant skill. Read multiple contracts for cross-domain work. Add a new canonical document only when no existing owner fits; link it from the map. When relocating knowledge, compare both sources and the destination, retain unique exceptions and rationale, and record corrections with code evidence. The [2026-09 migration ledger](../maintenance/agent-guidance-migration.md) records the initial move; it is an audit artifact, not required reading for feature work. Later normal edits maintain the canonical docs, not duplicate historical prose. Run `pnpm run agents:validate` after guidance changes. It checks line/byte budgets, root imports and local navigation links/anchors, including migration destinations. Line budgets count LF, CRLF and standalone CR endings consistently. Markdown navigation is parsed with the already-declared `marked` dependency; undefined explicit references (including shortcut images) are errors, and code examples are excluded. Backticked concrete paths in root guidance and the context map are checked from the repository root, including unknown top-level directories and filenames. Write generic filenames as prose; commands, templates, globs, URLs, package aliases and dotted code symbols are excluded. Bare dotted names with conventional file suffixes (such as .md, .json or .ts) are treated as filenames. Document formats share the suffix set used by package-import guards, including PDF and AsciiDoc. Use a `./` prefix or Markdown link for other ambiguous filenames that resemble code symbols. Explicit relative literals denote paths, including spaces, filesystem punctuation and hyphenated words. Put executable command examples in fenced code when their syntax also looks like a path. Multi-part dotfiles are path candidates too. Conventional extensionless filenames such as Dockerfile, Makefile and LICENSE are also path candidates; use an explicit `./` prefix for other extensionless files. Link paths and fragments are decoded separately so encoded filename delimiters stay in the filename. Fenced and indented examples do not count as root guidance imports or satisfy the required Claude import. The required Claude import must be an unformatted standalone line in a top-level paragraph; headings, quotes and list items do not satisfy it. The parsed HTML tree also verifies that this paragraph is outside HTML containers, including templates split across Markdown tokens. Generated HTML is inspected in memory only; it is never executed or emitted. Heading anchors decode HTML character references in text and use `github-slugger` for GitHub-compatible character filtering and duplicate suffixes. Only headings present outside inert HTML containers contribute slugs or duplicate counters. Explicit HTML anchors use `parse5`, excluding comments, scripts, styles and template contents. Rendered HTML anchor and image-map area hrefs and image sources use the same local-reference checks as Markdown links, including decoded attributes and fragment validation. URL attributes remove ASCII tabs/newlines throughout and discard surrounding ASCII control/space characters before resolution. Iframe/embed sources and object data attributes are document references and retain Markdown-target anchor checks. Inline iframe srcdoc documents are traversed too, with their own fragment anchors. The first active HTML base href sets reference resolution, including nested srcdoc bases. Resolved file URLs use native filesystem conversion, including Windows drive paths. Explicit srcset attributes must contain at least one parsed candidate. Image and media references require a nonempty path that resolves to a file, not a directory. Direct file URLs, Windows drive paths and HTML bases using either form are rejected; use portable repository-relative paths. Image references check file existence without interpreting image fragments as Markdown headings; document links keep anchor checks even when sharing a target. SVG image/use hrefs (including xlink), HTML image-input, video, audio, source and track `src` assets and video posters use the same existence checks as images. Entity decoding uses full HTML text/attribute rules, including references whose semicolon may be omitted. Inline guidance imports are rejected after punctuation as well as whitespace. At-signs inside external URIs (including www autolinks and explicit opaque autolinks such as mailto) are excluded per HTML text node, preserving adjacent imports. A colon directly before an import does not make that import a URI. Opaque schemes are excluded only in parsed links whose visible text equals their URI, so colon-labeled prose remains checked. A closing bracket or matching enclosing quote followed by punctuation and an at-sign terminates a bare URL exclusion. Extensionless inline candidates are also imports when they resolve to repository files, checking the full filename before prefixes at ASCII/Unicode prose separators, including opening parentheses, brackets and braces. Each at-sign candidate is checked independently, including imports nested next to a package mention. An at-sign inside a word (for example, foo@INSTRUCTIONS or an email address) is not an import boundary, including within parenthetical prose. Declared scoped dependencies, scope wildcards and matching TypeScript path aliases are recognized as package/alias mentions. Traversal and document-file imports are rejected before those exemptions, including document paths with fragments or queries. All recognized Markdown extensions share the document-import guard; reStructuredText and AsciiDoc, PDF, Word, OpenDocument, RTF, Org and TeX documents are also excluded from package exemptions. Recognized extensionless guidance names (including AGENTS, CLAUDE, INSTRUCTIONS, README, CONTRIBUTING and SECURITY, case-insensitively) are excluded in package subpaths too. URL-encoded paths do not receive package exemptions. TypeScript configuration is parsed as JSONC. Declared packages also permit safe subpaths; exact aliases stay exact. Federated handles in the @user@host form are prose, not imports; trailing closing ASCII/Unicode punctuation and possessive apostrophe-s suffixes are ignored. Opening delimiters separate adjacent prose; nested imports remain checked. Extra at-signs do not qualify for that exemption. Exact declared packages remain exempt after version normalization. Declared package mentions may include a version (including semver comparators and wildcard ranges) or dist-tag qualifier. Qualifier handling includes unscoped names; terminal sentence punctuation is removed before matching a declared package, as are straight/curly apostrophe possessives. Unicode punctuation and ASCII opening delimiters, commas, semicolons, colons, question/exclamation marks separate package mentions from adjacent prose. Markdown destinations decode HTML entities before URI parsing, matching rendered links. Heading-anchor lookup is limited to Markdown targets. Source-file line fragments, PDF page fragments and other non-Markdown fragments retain file-existence checks. The import scan separates HTML block/table elements and includes visible text and literal backticks; it excludes parsed code nodes and non-rendered containers. Navigation uses the parsed rendered tree too. Temporary in-memory markers retain definition, unresolved-reference and literal-path metadata, so Markdown inside inert templates is excluded consistently with raw HTML navigation. Image source sets use `parse-srcset` to check each candidate URL. Root-relative literals never suppress source-relative definition checks. The Nx test hash includes `marked`, `parse5`, `github-slugger`, `parse-srcset` and `typescript` so dependency changes invalidate parser coverage. It cannot prove semantic equivalence; review changed contracts as well. ## Protected Markdown edits Never run whole-file `prettier --write` on AGENTS.md, CLAUDE.md or docs/**. Upstream formatting is not uniformly Prettier-clean: whole-file writes can corrupt nested list indentation or change a literal continuation into a bullet. Format only intended new lines. If accidental formatting occurred, reconstruct from the pre-edit version and reapply only intended changes; preserve unrelated user edits. Use the merge-base version only if it actually represents that pre-edit state. Review the diff rather than blindly restoring an older branch. ## Plans and completion reports Save only finalized plans in `.plans/YYYY-MM-DD-short-topic.md`; use numeric suffixes for collisions. Do not save drafts or questions there. If an active mode forbids writes, save the approved plan on entering execution. Completion reports list changed docs, tests added/updated, commands and results, skipped validation with reasons, and release-note status. A docs-only task needs Markdown/link validation, not app unit/E2E tests. Tooling changes need their own tests. ## Repository skills Repository skills live under `.codex/skills/`. Descriptions are trigger-only, begin with `Use when`, and each skill is at most 500 words. Frontmatter owns trigger descriptions; avoid copying them into navigation prose. Skills provide workflow and links to authoritative contracts, not a second contract copy. `release-cut` and `release-notes` have byte-identical `.claude/skills/` mirrors. Run `pnpm run skills:validate` after changing a committed skill or a literal path it documents. New guidance tooling belongs to the existing `repository-skills` Nx project; no new project is needed for another validator. ## Angular conventions Use signal-based queries (`viewChild`, `viewChildren`, `contentChild`, `contentChildren`) and inputs/outputs (`input`, `output`). For required queries, use `viewChild.required`. Unwrap signals when passing values in templates: ```typescript readonly menu = viewChild.required('menuRef'); readonly title = input.required(); readonly size = input(10); readonly clicked = output(); readonly count = signal(0); readonly doubled = computed(() => this.count() * 2); ``` ```html ``` Use `signal`, `computed`, `effect` and `linkedSignal` for reactive state. Existing host bindings/listeners use `@HostBinding` and `@HostListener`; this relocation does not change that convention. Prefer `@if`, `@for` (with a stable `track`), and `@switch` over the legacy structural directives. A signal is a function; passing `menu` instead of `menu()` to Material supplies the wrong value. ## Adding behavior across layers For IPC, define the handler in the appropriate Electron events module, register it in the event bootstrap, expose a typed preload method, and consume it through the renderer service. Keep channel contracts typed in `ElectronBridgeApi`; use the database worker contract for heavy database work. See [Electron security](../architecture/electron-security.md) and [DB worker ownership](../architecture/sqlite-db-worker.md). For a playlist source, extend the shared playlist type, add the backend event handler, add the import UI under `libs/playlist/import/feature`, and update state actions/effects. Preserve runtime capabilities and migration behavior. NgRx owns M3U global state; portal/feature state uses composed NgRx Signal Store; component-local state uses Angular signals. Avoid expanding large classes: extract components/services or `with*` store features before exceeding limits; shared types belong in their own contract modules. The hard production limit is 400 (not a variable 350–400); target under 300. See [Nx file-size policy](../architecture/nx-workspace-boundaries.md#typescript-file-size). ## Build and serve commands Use local `pnpm nx` for underlying project targets. Package scripts are the supported entry points for composed tasks: | Task | Command | | --- | --- | | Web development | `pnpm run serve:frontend` | | PWA development | `pnpm nx serve web --configuration=pwa` | | Electron development | `pnpm run serve:backend` | | Electron frontend | `pnpm run build:frontend` | | PWA frontend | `pnpm run build:frontend:pwa` | | Electron backend | `pnpm run build:backend` | | Package without installers | `pnpm run package:app` | | Create installers | `pnpm run make:app` | Electron backend build depends on the web build; outputs live under `dist/apps/electron-backend` and `dist/apps/web` and packaging combines them. Use [the validation map](../architecture/validation-map.md) for test/lint tasks and [the release pipeline](../architecture/release-pipeline.md) for packaging. ## Shared search text folding Use `foldSearchText` from `libs/shared/interfaces/src/lib/search-text-fold.util.ts` on both sides of every in-memory search comparison. Channel lists, catalog and category filters, command palette, sources and downloads must share this fold; row filtering and count/queue sources must not diverge. It lowercases without a locale, normalizes to NFC, then strips remaining combining marks. Composing first keeps canonical spellings equivalent while preserving accents; the leftover dot in Turkish dotted İ is stripped so it matches plain i. Do not substitute `toLocaleLowerCase`. Electron content search uses the same fold and adds explicit Turkish-locale İ variants to LIKE/GLOB queries because SQLite LIKE folds only ASCII.