feat(skills): add Go, Python, Java, Rust skills + restructure language skills into optional plugins

.claude-plugin/marketplace.json

@@ -69,6 +69,62 @@
       "description": "Audit CLAUDE.md files against Anthropic best practices",
       "version": "1.1.0",
       "keywords": ["audit", "claude-md", "best-practices"]
+    },
+    {
+      "name": "devflow-typescript",
+      "source": "./plugins/devflow-typescript",
+      "description": "TypeScript language patterns (type safety, generics, utility types)",
+      "version": "1.1.0",
+      "keywords": ["typescript", "types", "generics"]
+    },
+    {
+      "name": "devflow-react",
+      "source": "./plugins/devflow-react",
+      "description": "React framework patterns (hooks, state, composition, performance)",
+      "version": "1.1.0",
+      "keywords": ["react", "hooks", "components"]
+    },
+    {
+      "name": "devflow-accessibility",
+      "source": "./plugins/devflow-accessibility",
+      "description": "Web accessibility patterns (WCAG, ARIA, keyboard navigation)",
+      "version": "1.1.0",
+      "keywords": ["accessibility", "wcag", "aria", "a11y"]
+    },
+    {
+      "name": "devflow-frontend-design",
+      "source": "./plugins/devflow-frontend-design",
+      "description": "Frontend design patterns (typography, color, spacing, motion)",
+      "version": "1.1.0",
+      "keywords": ["design", "typography", "css"]
+    },
+    {
+      "name": "devflow-go",
+      "source": "./plugins/devflow-go",
+      "description": "Go language patterns (error handling, interfaces, concurrency)",
+      "version": "1.1.0",
+      "keywords": ["go", "golang", "concurrency"]
+    },
+    {
+      "name": "devflow-python",
+      "source": "./plugins/devflow-python",
+      "description": "Python language patterns (type hints, protocols, data modeling)",
+      "version": "1.1.0",
+      "keywords": ["python", "type-hints", "dataclasses"]
+    },
+    {
+      "name": "devflow-java",
+      "source": "./plugins/devflow-java",
+      "description": "Java language patterns (records, sealed classes, composition)",
+      "version": "1.1.0",
+      "keywords": ["java", "records", "composition"]
+    },
+    {
+      "name": "devflow-rust",
+      "source": "./plugins/devflow-rust",
+      "description": "Rust language patterns (ownership, error handling, type system)",
+      "version": "1.1.0",
+      "keywords": ["rust", "ownership", "type-safety"]
     }
   ]
 }

CHANGELOG.md

@@ -5,6 +5,40 @@ All notable changes to DevFlow will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+- **Polyglot language skills** — Go, Java, Python, and Rust skill plugins with comprehensive patterns
+  - Go: error handling, interfaces, concurrency (errgroup, worker pools, fan-out/fan-in)
+  - Java: records, sealed classes, streams, composition over inheritance
+  - Python: type hints, protocols, dataclasses, async patterns
+  - Rust: ownership, error handling (`thiserror`/`anyhow`), type system, concurrency
+  - Skills: 26 → 30, Plugins: 9 → 17
+- **Optional plugin architecture** — Language/ecosystem plugins (`optional: true`) not installed by default
+  - Install selectively: `devflow init --plugin=go --plugin=python`
+  - Existing skills (typescript, react, accessibility, frontend-design) moved to optional plugins
+  - `devflow-core-skills` no longer bundles language-specific skills
+- **Conditional language reviews** in `/code-review` command
+  - Spawns language-specific Reviewer agents when matching files are in the diff
+  - Skill availability check: skips review if optional plugin not installed
+- **Dynamic skill loading in Coder agent** — Reads language skills at runtime based on DOMAIN hint instead of static frontmatter dependencies
+
+### Changed
+- **`devflow-core-skills`** no longer includes typescript, react, accessibility, or frontend-design skills (moved to optional plugins)
+- **Coder agent** frontmatter trimmed from 14 skills to 6 core skills; language skills loaded dynamically
+
+### Fixed
+- **Deprecated `grpc.WithInsecure()`** in Go concurrency examples → replaced with `grpc.WithTransportCredentials(insecure.NewCredentials())`
+- **Deprecated `datetime.utcnow`** in Python dataclass example → replaced with `datetime.now(timezone.utc)`
+- **SQL injection** in Python async streaming example → replaced raw query with parameterized query
+- **Deprecated `<Context.Provider>`** in React examples → replaced with `<Context>` (React 19+)
+- **Deprecated `useRef<T>()`** without argument in React patterns → replaced with `useRef<T | undefined>(undefined)` (React 19+)
+- **Non-portable `NodeJS.Timeout`** in TypeScript debounce/throttle → replaced with `ReturnType<typeof setTimeout>`
+- **Unsafe `Function` type** in TypeScript type guard → replaced with `(...args: unknown[]) => unknown`
+- **Go test file exclusion** removed from go skill activation (test files are valid Go code)
+
+---
+
 ## [1.1.0] - 2026-03-04
 
 ### Added

CLAUDE.md

@@ -12,7 +12,7 @@ DevFlow enhances Claude Code with intelligent development workflows. Modificatio
 
 ## Architecture Overview
 
-Plugin marketplace with 9 self-contained plugins, each following the Claude plugins format (`.claude-plugin/plugin.json`, `commands/`, `agents/`, `skills/`).
+Plugin marketplace with 17 plugins (9 core + 8 optional language/ecosystem), each following the Claude plugins format (`.claude-plugin/plugin.json`, `commands/`, `agents/`, `skills/`).
 
 | Plugin | Purpose | Teams Variant |
 |--------|---------|---------------|
@@ -25,6 +25,14 @@ Plugin marketplace with 9 self-contained plugins, each following the Claude plug
 | `devflow-ambient` | Ambient mode — auto-loads relevant skills based on each prompt | No |
 | `devflow-core-skills` | Auto-activating quality enforcement | No |
 | `devflow-audit-claude` | Audit CLAUDE.md files (optional) | No |
+| `devflow-typescript` | TypeScript language patterns (optional) | No |
+| `devflow-react` | React framework patterns (optional) | No |
+| `devflow-accessibility` | Web accessibility patterns (optional) | No |
+| `devflow-frontend-design` | Frontend design patterns (optional) | No |
+| `devflow-go` | Go language patterns (optional) | No |
+| `devflow-python` | Python language patterns (optional) | No |
+| `devflow-java` | Java language patterns (optional) | No |
+| `devflow-rust` | Rust language patterns (optional) | No |
 
 Commands with Teams Variant ship as `{name}.md` (parallel subagents) and `{name}-teams.md` (Agent Teams with debate). The installer copies the chosen variant based on `--teams`/`--no-teams` flag.
 
@@ -36,9 +44,9 @@ Commands with Teams Variant ship as `{name}.md` (parallel subagents) and `{name}
 
 ```
 devflow/
-├── shared/skills/          # 26 skills (single source of truth)
+├── shared/skills/          # 30 skills (single source of truth)
 ├── shared/agents/          # 10 shared agents (single source of truth)
-├── plugins/devflow-*/      # 9 self-contained plugins
+├── plugins/devflow-*/      # 17 plugins (9 core + 8 optional language/ecosystem)
 ├── docs/reference/         # Detailed reference documentation
 ├── scripts/                # Helper scripts (statusline, docs-helpers)
 │   └── hooks/              # Working Memory + ambient hooks (stop, session-start, pre-compact, ambient-prompt)

README.md

@@ -24,7 +24,7 @@ DevFlow adds structured commands that handle the full lifecycle: specify feature
 - **Full-lifecycle implementation** — spec, explore, plan, code, validate, refine in one command
 - **Automatic session memory** — survives restarts, `/clear`, and context compaction
 - **Parallel debugging** — competing hypotheses investigated simultaneously
-- **26 quality skills** — 12 auto-activating, plus specialized review and agent skills
+- **30 quality skills** — 8 auto-activating core, 8 optional language/ecosystem, plus specialized review and agent skills
 
 ## Quick Start
 
@@ -81,7 +81,7 @@ Creates a PR when complete.
 Multi-perspective code review with specialized reviewers:
 
 - **Core**: Security, Architecture, Performance, Quality
-- **Conditional** (activated when relevant): TypeScript, React, Accessibility, Database, Dependencies, Documentation
+- **Conditional** (activated when relevant): TypeScript, React, Accessibility, Go, Python, Java, Rust, Database, Dependencies, Documentation
 - Findings classified as must-fix, should-fix, or nit with severity and confidence levels
 
 Provides actionable feedback with specific file locations and suggested fixes.
@@ -120,10 +120,27 @@ The `devflow-core-skills` plugin provides quality enforcement skills that activa
 | `test-driven-development` | Implementing new features (RED-GREEN-REFACTOR) |
 | `test-patterns` | Writing or modifying tests |
 | `input-validation` | Creating API endpoints |
-| `typescript` | Working in TypeScript codebases |
-| `react` | Working with React components |
-| `accessibility` | Creating UI components, forms, interactive elements |
-| `frontend-design` | Working with CSS, styling, visual design |
+
+## Language & Ecosystem Plugins
+
+Optional plugins for language-specific patterns. Install only what you need:
+
+| Plugin | Skill | Triggers When |
+|--------|-------|---------------|
+| `devflow-typescript` | `typescript` | Working in TypeScript codebases |
+| `devflow-react` | `react` | Working with React components |
+| `devflow-accessibility` | `accessibility` | Creating UI components, forms |
+| `devflow-frontend-design` | `frontend-design` | Working with CSS, styling |
+| `devflow-go` | `go` | Working in Go codebases |
+| `devflow-python` | `python` | Working in Python codebases |
+| `devflow-java` | `java` | Working in Java codebases |
+| `devflow-rust` | `rust` | Working in Rust codebases |
+
+```bash
+# Install specific language plugins
+npx devflow-kit init --plugin=typescript,react
+npx devflow-kit init --plugin=go
+```
 
 ## Requirements
 

docs/reference/skills-architecture.md

@@ -57,6 +57,10 @@ Language and framework patterns. Referenced by agents via frontmatter and condit
 | `react` | Components, hooks, state management, performance | React codebases |
 | `accessibility` | Keyboard, ARIA, focus, color contrast | Frontend codebases |
 | `frontend-design` | Typography, color, spacing, visual design | Frontend codebases |
+| `go` | Error handling, interfaces, concurrency, package design | Go codebases |
+| `python` | Type hints, protocols, dataclasses, async patterns | Python codebases |
+| `java` | Records, sealed classes, composition, modern Java | Java codebases |
+| `rust` | Ownership, borrowing, error handling, type-driven design | Rust codebases |
 
 ## How Skills Activate
 
@@ -184,6 +188,10 @@ activation:
 | `typescript` | `**/*.ts`, `**/*.tsx` | `node_modules/**`, `**/*.d.ts` |
 | `accessibility` | `**/*.tsx`, `**/*.jsx`, `**/*.css` | `node_modules/**` |
 | `frontend-design` | `**/*.tsx`, `**/*.jsx`, `**/*.css`, `**/*.scss` | `node_modules/**` |
+| `go` | `**/*.go` | `vendor/**` |
+| `python` | `**/*.py` | `venv/**`, `.venv/**`, `**/__pycache__/**` |
+| `java` | `**/*.java` | `**/build/**`, `**/target/**` |
+| `rust` | `**/*.rs` | `**/target/**` |
 | `test-patterns` | `**/*.test.*`, `**/*.spec.*`, `**/test/**` | `node_modules/**` |
 
 **Note:** Glob patterns are metadata hints for documentation. Claude Code does not currently read glob patterns to trigger skills — activation happens through agent frontmatter and Reviewer dynamic read (see "How Skills Activate" above).

plugins/devflow-accessibility/.claude-plugin/plugin.json

@@ -0,0 +1,15 @@
+{
+  "name": "devflow-accessibility",
+  "description": "Web accessibility patterns - WCAG compliance, ARIA roles, keyboard navigation, focus management",
+  "author": {
+    "name": "DevFlow Contributors",
+    "email": "dean@keren.dev"
+  },
+  "version": "1.1.0",
+  "homepage": "https://github.com/dean0x/devflow",
+  "repository": "https://github.com/dean0x/devflow",
+  "license": "MIT",
+  "keywords": ["accessibility", "wcag", "aria", "a11y"],
+  "agents": [],
+  "skills": ["accessibility"]
+}

plugins/devflow-code-review/.claude-plugin/plugin.json

@@ -12,17 +12,14 @@
   "keywords": ["review", "code-quality", "security", "architecture", "pr-review"],
   "agents": ["git", "reviewer", "synthesizer"],
   "skills": [
-    "accessibility",
     "agent-teams",
     "architecture-patterns",
     "complexity-patterns",
     "consistency-patterns",
     "database-patterns",
     "dependencies-patterns",
     "documentation-patterns",
-    "frontend-design",
     "performance-patterns",
-    "react",
     "regression-patterns",
     "review-methodology",
     "security-patterns",

plugins/devflow-code-review/commands/code-review-teams.md

@@ -42,10 +42,16 @@ Detect file types in diff to determine conditional reviews:
 | .tsx/.jsx files | react |
 | .tsx/.jsx files | accessibility |
 | .tsx/.jsx/.css/.scss files | frontend-design |
+| .go files | go |
+| .java files | java |
+| .py files | python |
+| .rs files | rust |
 | DB/migration files | database |
 | Dependency files changed | dependencies |
 | Docs or significant code | documentation |
 
+**Skill availability check**: Language/ecosystem reviews (typescript, react, accessibility, frontend-design, go, java, python, rust) require their optional skill plugin to be installed. Before adding a conditional perspective, check if `~/.claude/skills/{focus}/SKILL.md` exists (use Glob). If the skill file doesn't exist, **skip that perspective** — the language plugin isn't installed. Non-language reviews (database, dependencies, documentation) use skills bundled with this plugin and are always available.
+
 ### Phase 2: Spawn Review Team
 
 Create an agent team for adversarial review. Always include 4 core perspectives; conditionally add more based on Phase 1 analysis.
@@ -61,6 +67,10 @@ Create an agent team for adversarial review. Always include 4 core perspectives;
 - **React**: hooks, state, rendering, composition (if .tsx/.jsx changed)
 - **Accessibility**: ARIA, keyboard nav, focus management (if .tsx/.jsx changed)
 - **Frontend Design**: visual consistency, spacing, typography (if .tsx/.jsx/.css changed)
+- **Go**: error handling, interfaces, concurrency (if .go changed)
+- **Java**: records, sealed classes, composition (if .java changed)
+- **Python**: type hints, protocols, data modeling (if .py changed)
+- **Rust**: ownership, error handling, type system (if .rs changed)
 - **Database**: schema, queries, migrations, indexes (if DB files changed)
 - **Dependencies**: CVEs, versions, licenses, supply chain (if package files changed)
 - **Documentation**: doc drift, missing docs, stale comments (if docs or significant code changed)
@@ -238,7 +248,7 @@ Display results:
 │  ├─ Architecture Reviewer (teammate)
 │  ├─ Performance Reviewer (teammate)
 │  ├─ Quality Reviewer (teammate)
-│  └─ [Conditional: TypeScript, React, A11y, Design, DB, Deps, Docs]
+│  └─ [Conditional: TypeScript, React, A11y, Design, Go, Java, Python, Rust, DB, Deps, Docs]
 │
 ├─ Phase 3: Debate round
 │  └─ Reviewers challenge each other (max 2 rounds)

plugins/devflow-code-review/commands/code-review.md

@@ -42,13 +42,19 @@ Detect file types in diff to determine conditional reviews:
 | .tsx/.jsx files | react |
 | .tsx/.jsx files | accessibility |
 | .tsx/.jsx/.css/.scss files | frontend-design |
+| .go files | go |
+| .java files | java |
+| .py files | python |
+| .rs files | rust |
 | DB/migration files | database |
 | Dependency files changed | dependencies |
 | Docs or significant code | documentation |
 
+**Skill availability check**: Language/ecosystem reviews (typescript, react, accessibility, frontend-design, go, java, python, rust) require their optional skill plugin to be installed. Before spawning a conditional Reviewer for these focuses, check if `~/.claude/skills/{focus}/SKILL.md` exists (use Glob). If the skill file doesn't exist, **skip that review** — the language plugin isn't installed. Non-language reviews (database, dependencies, documentation) use skills bundled with this plugin and are always available.
+
 ### Phase 2: Run Reviews (Parallel)
 
-Spawn Reviewer agents **in a single message**. Always run 7 core reviews; conditionally add up to 4 more:
+Spawn Reviewer agents **in a single message**. Always run 7 core reviews; conditionally add more based on changed file types:
 
 | Focus | Always | Pattern Skill |
 |-------|--------|---------------|
@@ -63,6 +69,10 @@ Spawn Reviewer agents **in a single message**. Always run 7 core reviews; condit
 | react | conditional | react |
 | accessibility | conditional | accessibility |
 | frontend-design | conditional | frontend-design |
+| go | conditional | go |
+| java | conditional | java |
+| python | conditional | python |
+| rust | conditional | rust |
 | database | conditional | database-patterns |
 | dependencies | conditional | dependencies-patterns |
 | documentation | conditional | documentation-patterns |
@@ -123,7 +133,7 @@ Display results from all agents:
 │  ├─ Reviewer: consistency
 │  ├─ Reviewer: regression
 │  ├─ Reviewer: tests
-│  └─ Reviewer: [conditional: typescript, react, a11y, design, database, deps, docs]
+│  └─ Reviewer: [conditional: typescript, react, a11y, design, go, java, python, rust, database, deps, docs]
 │
 ├─ Phase 3: Synthesis (PARALLEL)
 │  ├─ Git agent (comment-pr)

plugins/devflow-core-skills/.claude-plugin/plugin.json

@@ -12,17 +12,13 @@
   "keywords": ["skills", "quality", "patterns", "auto-activate", "enforcement", "foundation"],
   "agents": [],
   "skills": [
-    "accessibility",
     "core-patterns",
     "docs-framework",
-    "frontend-design",
     "git-safety",
     "git-workflow",
     "github-patterns",
     "input-validation",
-    "react",
     "test-driven-development",
-    "test-patterns",
-    "typescript"
+    "test-patterns"
   ]
 }

plugins/devflow-frontend-design/.claude-plugin/plugin.json

@@ -0,0 +1,15 @@
+{
+  "name": "devflow-frontend-design",
+  "description": "Frontend design patterns - typography, color systems, spacing, motion, responsive design",
+  "author": {
+    "name": "DevFlow Contributors",
+    "email": "dean@keren.dev"
+  },
+  "version": "1.1.0",
+  "homepage": "https://github.com/dean0x/devflow",
+  "repository": "https://github.com/dean0x/devflow",
+  "license": "MIT",
+  "keywords": ["design", "typography", "color", "css"],
+  "agents": [],
+  "skills": ["frontend-design"]
+}

plugins/devflow-go/.claude-plugin/plugin.json

@@ -0,0 +1,15 @@
+{
+  "name": "devflow-go",
+  "description": "Go language patterns - error handling, interfaces, concurrency, package design",
+  "author": {
+    "name": "DevFlow Contributors",
+    "email": "dean@keren.dev"
+  },
+  "version": "1.1.0",
+  "homepage": "https://github.com/dean0x/devflow",
+  "repository": "https://github.com/dean0x/devflow",
+  "license": "MIT",
+  "keywords": ["go", "golang", "concurrency", "errors"],
+  "agents": [],
+  "skills": ["go"]
+}

plugins/devflow-implement/.claude-plugin/plugin.json

@@ -12,9 +12,7 @@
   "keywords": ["implementation", "coding", "workflow", "agents", "agentic", "pr"],
   "agents": ["git", "skimmer", "synthesizer", "coder", "simplifier", "scrutinizer", "shepherd", "validator"],
   "skills": [
-    "accessibility",
     "agent-teams",
-    "frontend-design",
     "implementation-patterns",
     "self-review"
   ]