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Kandev Engineering Guide
Purpose: Architecture notes, key patterns, and conventions for LLM agents working on Kandev.
Repo Layout
apps/
├── backend/ # Go backend (orchestrator, agent runtime, agentctl, WS gateway)
├── web/ # Next.js frontend (SSR + WS + Zustand)
├── cli/ # CLI tool (TypeScript)
├── landing/ # Landing page
└── packages/ # Shared packages/types
Tooling
- Package manager:
pnpmworkspace (run fromapps/, not repo root) - Backend: Go with Make (
make -C apps/backend test|lint|build) - Frontend: Next.js (
cd apps && pnpm --filter @kandev/web dev|lint|typecheck) - UI: Shadcn components via
@kandev/ui - GitHub repo:
https://github.com/kdlbs/kandev - Container image:
ghcr.io/kdlbs/kandev(GitHub Container Registry) - Dev mock providers: In
KANDEV_MOCK_AGENT=truedev mode the basemock-agentis enabled alongside the real CLIs. To exercise the office provider-routing UI without installing real CLIs, setKANDEV_MOCK_PROVIDERS=claude-acp,codex-acp,opencode-acp(or any subset ofRoutableProviderIDs) when launchingmake dev— those canonicals are then replaced with MockAgent aliases.
Worktrees and commit hooks
The commit-msg hook runs cd apps && pnpm exec commitlint --edit "$1". A fresh git worktree shares .git/ but not apps/node_modules/, so the first commit attempted in a worktree fails with Command "commitlint" not found / ERR_PNPM_RECURSIVE_EXEC_FIRST_FAIL. Run pnpm install --frozen-lockfile from apps/ in the worktree once before the first commit; subsequent commits work normally.
Backend Architecture
Package Structure
apps/backend/
├── cmd/
│ ├── kandev/ # Main backend binary entry point
│ ├── agentctl/ # Agentctl binary (runs inside containers or standalone)
│ └── mock-agent/ # Mock agent for testing
├── internal/
│ ├── agent/
│ │ ├── runtime/ # Agent runtime: single seam for Launch/Resume/Stop/observe
│ │ │ ├── lifecycle/ # Agent instance management (moved from agent/lifecycle)
│ │ │ ├── agentctl/ # HTTP client for talking to agentctl (moved from agentctl/client)
│ │ │ └── routingerr/ # Provider error classifier + sanitizer + ProviderProber registry
│ │ ├── agents/ # Agent type implementations
│ │ ├── controller/ # Agent control operations
│ │ ├── credentials/ # Agent credential management
│ │ ├── discovery/ # Agent discovery
│ │ ├── docker/ # Docker-specific agent logic
│ │ ├── dto/ # Agent data transfer objects
│ │ ├── executor/ # Executor types, checks, and service
│ │ ├── handlers/ # Agent event handlers
│ │ ├── registry/ # Agent type registry and defaults
│ │ ├── settings/ # Agent settings
│ │ ├── mcpconfig/ # MCP server configuration
│ │ └── remoteauth/ # Remote auth catalog and method IDs for remote executors/UI
│ ├── agentctl/
│ │ └── server/ # agentctl HTTP server
│ │ ├── acp/ # ACP protocol implementation
│ │ ├── adapter/ # Protocol adapters + transport/ (ACP, Codex, OpenCode, Copilot, Amp)
│ │ ├── api/ # HTTP endpoints
│ │ ├── config/ # agentctl configuration
│ │ ├── instance/ # Multi-instance management
│ │ ├── mcp/ # MCP server integration
│ │ ├── process/ # Agent subprocess management
│ │ ├── shell/ # Shell session management
│ │ └── utility/ # agentctl utilities
│ ├── orchestrator/ # Task execution coordination
│ │ ├── dto/ # Orchestrator data transfer objects
│ │ ├── executor/ # Launches agents via lifecycle manager
│ │ ├── handlers/ # Orchestrator event handlers
│ │ ├── messagequeue/ # Message queue for agent prompts
│ │ ├── queue/ # Task queue
│ │ ├── scheduler/ # Task scheduling
│ │ └── watcher/ # Event handlers
│ ├── task/
│ │ ├── controller/ # Task HTTP/WS controllers
│ │ ├── dto/ # Task data transfer objects
│ │ ├── events/ # Task event types
│ │ ├── handlers/ # Task event handlers
│ │ ├── models/ # Task, Session, Executor, Message models
│ │ ├── repository/ # Database access (SQLite)
│ │ └── service/ # Task business logic
│ ├── office/ # Autonomous agent management (Office feature)
│ │ ├── agents/ # Agent instance CRUD + auth guards
│ │ ├── approvals/ # Approval requests and decisions
│ │ ├── channels/ # External integration channels (webhooks)
│ │ ├── config/ # Config sync (DB ↔ filesystem)
│ │ ├── configloader/ # Filesystem config reader/writer
│ │ ├── costs/ # Cost tracking and budget policies
│ │ ├── dashboard/ # Dashboard API, issues, activity, live runs
│ │ ├── infra/ # GC, reconciliation
│ │ ├── labels/ # Task labels
│ │ ├── onboarding/ # Workspace onboarding wizard API
│ │ ├── projects/ # Project management
│ │ ├── repository/ # Office SQLite persistence
│ │ ├── runtime/ # Agent run context, capabilities, and runtime action surface
│ │ ├── routines/ # Scheduled recurring tasks
│ │ ├── routing/ # Provider routing: resolver, validators, catalogue, backoff, agent-overrides
│ │ ├── scheduler/ # Wakeup scheduler (duplicate of service scheduler features)
│ │ ├── service/ # Core office service (wakeups, event subscribers, execution policy)
│ │ ├── shared/ # Shared interfaces and activity logging
│ │ ├── skills/ # Skill injection and materialization
│ │ └── workspaces/ # Workspace deletion handler
│ ├── events/ # Event bus for internal pub/sub
│ ├── gateway/ # WebSocket gateway
│ ├── github/ # GitHub API integration (PRs, reviews, webhooks)
│ ├── common/ # Shared utilities, config, logger
│ ├── integration/ # External integrations
│ ├── integrations/ # Shared shapes for third-party integrations
│ │ ├── healthpoll/ # Reusable 90s auth-health Poller (used by jira, linear)
│ │ └── secretadapter/ # Upsert-style adapter over secrets.SecretStore
│ ├── jira/ # Jira/Atlassian Cloud integration (config, REST client, poller)
│ ├── linear/ # Linear integration (config, GraphQL client, poller)
│ ├── lsp/ # LSP server
│ ├── mcp/ # MCP protocol support
│ ├── health/ # Health check endpoints
│ ├── notifications/ # Notification system
│ ├── persistence/ # Persistence layer
│ ├── prompts/ # Prompt management
│ ├── repoclone/ # Repository cloning for remote executors
│ ├── scriptengine/ # Script placeholder resolution and interpolation
│ ├── secrets/ # Secret management
│ ├── sprites/ # Sprites AI integration
│ ├── sysprompt/ # System prompt injection
│ ├── task/
│ │ └── ...
│ ├── tools/ # Tool integrations
│ ├── user/ # User management
│ ├── utility/ # Shared utility functions
│ ├── workflow/ # Workflow engine
│ │ ├── engine/ # Typed state-machine engine
│ │ ├── models/ # Workflow step, template, and history models
│ │ ├── repository/ # Workflow persistence (SQLite)
│ │ └── service/ # Workflow CRUD and step resolution
│ └── worktree/ # Git worktree management for workspace isolation
Key Concepts
Orchestrator coordinates task execution:
- Receives task start/stop/resume requests via WebSocket
- Delegates to lifecycle manager for agent operations
- Handles event-driven state transitions via workflow engine
- Located in
internal/orchestrator/
Workflow Engine (internal/workflow/engine/) provides typed state-machine evaluation:
Engine.HandleTrigger()evaluates step actions for triggers (on_enter, on_turn_start, on_turn_complete, on_exit)TransitionStoreinterface abstracts persistence (implemented byorchestrator.workflowStore)CallbackRegistrymaps action kinds to callbacks (plan mode, auto-start, context reset)- First-transition-wins: multiple transition actions in one trigger, first eligible wins
EvaluateOnlymode: engine evaluates without persisting, caller orchestrates on_exit → DB → on_enterRequiresApprovalon actions: transitions requiring review gating are skipped- Idempotent by
OperationID; session-scoped data bag viaMachineState.Data
Agent Runtime (internal/agent/runtime/) is the single seam for launching, resuming, stopping, and observing agent executions. ADR 0004 introduced this in Phase 1 of task-model-unification. The public surface is runtime.Runtime (runtime.go); a thin facade (facade.go) delegates to a Backend (satisfied by *lifecycle.Manager).
Convention: only internal/agent/runtime/ (and code that pre-dates Phase 1 migration) may import runtime/lifecycle or runtime/agentctl directly. New consumers — workflow engine actions, cron-driven trigger handlers, future task-tier callers — should depend on runtime.Runtime. Existing call sites are migrated through later phases of task-model-unification.
Lifecycle Manager (internal/agent/runtime/lifecycle/) manages agent instances under the runtime:
Manager(manager.go,manager_*.go) - central coordinator for agent lifecycleExecutorBackendinterface (executor_backend.go) - abstracts execution environment (Docker, Standalone, Sprites, Remote Docker)ExecutionStore(execution_store.go) - thread-safe in-memory execution trackingsession.go- ACP session initialization and resumestreams.go- WebSocket stream connections to agentctlprocess_runner.go- agent process launch and managementprofile_resolver.go- resolves agent profiles/settings
agentctl client (internal/agent/runtime/agentctl/) is the HTTP/WS client used by the lifecycle manager to talk to a running agentctl instance. It is a runtime-tier package and should not be imported outside internal/agent/runtime/.
agentctl is an HTTP server that:
- Runs inside Docker containers or as standalone process
- Manages agent subprocess via stdin/stdout (ACP protocol)
- Exposes workspace operations (shell, git, files)
- Supports multiple concurrent instances on different ports
Executor Types (database model):
local_pc- Standalone process on host ✅local_docker- Docker container on host ✅sprites- Sprites cloud environment ✅remote_docker,remote_vps,k8s- Planned
Execution Flow
Client (WS) → Orchestrator → Lifecycle Manager → ExecutorBackend (container/process) → agentctl
↓
Client (WS) ← Orchestrator ← Lifecycle Manager ←──── stream updates (WS) ──────── agent subprocess
- Orchestrator receives
session.launchvia WS - Lifecycle Manager creates executor instance (container or process)
- agentctl starts inside the instance, agent subprocess is configured and started
- Agent events stream back via WS through the chain
Session Resume: TaskSession.ACPSessionID stored for resume; ExecutorRunning tracks active state; on restart RecoverInstances() reconnects.
Provider Pattern: Packages expose Provide(cfg, log) (*impl, cleanup, error) for DI. Returns implementation, cleanup function, and error. Cleanup called during graceful shutdown.
Worktrees: internal/worktree/Manager provides workspace isolation. Each session can have its own worktree (branch) to prevent conflicts between concurrent agents.
Executor default scripts: Default prepare scripts are in internal/agent/runtime/lifecycle/default_scripts.go; internal/scriptengine/ handles placeholder resolution.
agentctl Server
API Groups
agentctl exposes these route groups (see internal/agentctl/server/api/):
/health,/info,/status- Health and status/instances/*- Multi-instance management/processes/*- Agent subprocess management (start/stop)/agent/configure,/agent/stream- Agent configuration and event streaming/git/*- Git operations (status, commit, push, pull, rebase, stage, etc.)/shell/*- Shell session management/workspace/*- File operations, search, tree/vscode/*- VS Code integration proxy
Adapter Model
Protocol adapters in adapter/transport/ normalize different agent CLIs:
AgentAdapterinterface definesStart(),Stop(),Prompt(),Cancel()- Transports:
acp(Claude Code),codex(OpenAI Codex),opencode,shared,streamjson - Top-level adapters:
CopilotAdapter(GitHub Copilot SDK),AmpAdapter(Sourcegraph Amp) process.Managerowns subprocess, wires stdio to adapter- Factory pattern in
adapter/factory.goselects adapter by agent type
ACP Protocol
JSON-RPC 2.0 over stdin/stdout between agentctl and agent process. Requests: initialize, session/new, session/load, session/prompt, session/cancel. Notifications: session/update with types message_chunk, tool_call, tool_update, complete, error, permission_request, context_window.
Frontend Architecture
UI Components
Shadcn Components: Import from @kandev/ui package:
import { Badge } from '@kandev/ui/badge';
import { Button } from '@kandev/ui/button';
import { Dialog } from '@kandev/ui/dialog';
// etc...
Do NOT import from @/components/ui/* - always use @kandev/ui package.
Data Flow Pattern (Critical)
SSR Fetch -> Hydrate Store -> Components Read Store -> Hooks Subscribe
Never fetch data directly in components.
Store Structure (Domain Slices)
lib/state/
├── store.ts # Root composition
├── default-state.ts # Default state + initial state merge
├── slices/ # Domain slices
│ ├── kanban/ # boards, tasks, columns
│ ├── session/ # sessions, messages, turns, worktrees
│ ├── session-runtime/ # shell, processes, git, context
│ ├── workspace/ # workspaces, repos, branches
│ ├── settings/ # executors, agents, editors, prompts (incl. userSettings)
│ ├── office/ # office agents, skills, projects, dashboard, issues
│ ├── comments/ # code review diff comments
│ ├── github/ # GitHub PRs, reviews
│ └── ui/ # preview, connection, active state, sidebar views
├── hydration/ # SSR merge strategies
hooks/domains/{kanban,session,workspace,settings,comments,github}/ # Domain-organized hooks
lib/api/domains/ # API clients
├── kanban-api, session-api, workspace-api, settings-api, process-api
├── plan-api, queue-api, workflow-api, stats-api, github-api
├── office-api, office-extended-api, tree-api
├── user-shell-api, debug-api, secrets-api, sprites-api, vscode-api
├── health-api, utility-api
Key State Paths:
messages.bySession[sessionId],shell.outputs[sessionId],gitStatus.bySessionId[sessionId]tasks.activeTaskId,tasks.activeSessionId,workspaces.activeIdrepositories.byWorkspace,repositoryBranches.byRepository
Hydration: lib/state/hydration/merge-strategies.ts has deepMerge(), mergeSessionMap(), mergeLoadingState() to avoid overwriting live client state. Pass activeSessionId to protect active sessions.
Hooks Pattern: Hooks in hooks/domains/ encapsulate WS subscription + store selection. WS client deduplicates subscriptions automatically.
WS
Format: {id, type, action, payload, timestamp}.
Best Practices
Commit Conventions (enforced by CI)
Commits to main must follow Conventional Commits (type: description). PRs are squash-merged — the PR title becomes the commit, validated by CI. Changelog is auto-generated from these via git-cliff (cliff.toml). See .agents/skills/commit/SKILL.md for allowed types and examples.
Release & Versioning
Kandev uses a single SemVer X.Y.Z across npm, Homebrew, and GitHub release; release flow runs entirely in CI via .github/workflows/release.yml. Full details in the /release skill — load it when cutting a release or debugging release artifacts.
Code Quality (enforced by linters)
Static analysis runs in CI and pre-commit. New code must stay within these limits:
Go (apps/backend/.golangci.yml - errors on new code only):
- Functions: ≤80 lines, ≤50 statements
- Cyclomatic complexity: ≤15 · Cognitive complexity: ≤30
- Nesting depth: ≤5 · Naked returns only in functions ≤30 lines
- No duplicated blocks (≥150 tokens) · Repeated strings → constants (≥3 occurrences)
TypeScript (apps/web/eslint.config.mjs - warnings, will become errors):
- Files: ≤600 lines · Functions: ≤100 lines
- Cyclomatic complexity: ≤15 · Cognitive complexity: ≤20
- Nesting depth: ≤4 · Parameters: ≤5
- No duplicated strings (≥4 occurrences) · No identical functions · No unused imports
- No nested ternaries
When you hit a limit: extract a helper function, custom hook, or sub-component. Prefer composition over growing a single function.
Testing
Every code change must include tests for new or changed logic. Backend: *_test.go files alongside the source. Frontend: *.test.ts files for utility functions, hooks, API clients, and store slices. Exceptions: config files, generated code, React component markup. Use /tdd for test-driven development.
Knowledge
- Specs: Feature specs live in
docs/specs/<slug>/spec.md— the "what & why" of a feature, written before coding. Optional siblings:plan.md(how),notes.md(post-ship). Use/specto write or update a spec. Seedocs/specs/INDEX.md. - Decisions: Architecture decisions are recorded in
docs/decisions/. Readdocs/decisions/INDEX.mdfor an overview. When making significant architectural choices, create a new ADR via/record decision. - Plans: Implementation plans are generated from specs via
/planand saved todocs/specs/<slug>/plan.md. Plans are gitignored (working files, not committed) — only specs and ADRs are tracked.
Backend
- Provider pattern for DI; stderr for logs, stdout for ACP only
- Pass context through chains; event bus for cross-component comm
- Execution access: Workspace-oriented handlers (files, shell, inference, ports, vscode, LSP) MUST use
GetOrEnsureExecution(ctx, sessionID)— it recovers from backend restarts by creating executions on-demand. Only useGetExecutionBySessionIDfor operations that require a running agent process (prompt, cancel, mode). - Task lifecycle events: Any code path that mutates a task row must publish via the event bus (
task.created/task.updated/task.deleted) — either by going throughService.CreateTask/UpdateTask/DeleteTask/ArchiveTask, or by callingpublishTaskEvent(or one of thePublish*helpers inservice_events.go) directly. Walkingrepository.TaskRepositorystraight bypasses event publishing and breaks WS-driven UI like the All-Workflows kanban view.HandoffService's cascade methods learned this the hard way — they now require aTaskEventPublisherwired viaSetTaskEventPublisher. New cascade / bulk / cleanup paths must follow the same pattern. - Testing: Prefer
testing/synctest(Go 1.24+) overtime.Sleepfor time-dependent tests. Usesynctest.Testto wrap tests with tickers or timeouts — it advances fake time instantly when all goroutines are idle. Whensynctestis not feasible (e.g., tests spawning external processes likegit), use channel-based synchronization (<-started, non-blockingselect) instead of sleep-based waits. Reservetime.Sleeponly for integration tests that need real subprocess execution time.
Backups
- On every SQLite boot,
persistence.Providereadskandev_meta.kandev_version. If the stored version differs from the binary version (or any user tables exist but no version is recorded), it takes aVACUUM INTOsnapshot into<data-dir>/backups/before running migrations. - Retention: 2 backups kept (newest two by mtime); older ones are pruned after the snapshot succeeds.
- Postgres: backup is skipped with a log line. Use
pg_dumpfor Postgres backups. - Boot aborts if the backup fails -- the pool is closed and
Providereturns an error. - After all repos complete
initSchema,cmd/kandev/storage.go:recordSchemaVersionwrites the current binary version intokandev_meta(non-fatal; a failure just means the next boot will take a fresh snapshot). - Migration logging:
db.MigrateLogger.Apply(name, stmt)-- success logs Info, "already exists"/"duplicate column name" is silently swallowed, anything else logs Warn but never returns an error (preserving the existing swallow-error contract).
Frontend
- Data: SSR fetch → hydrate → read store. Never fetch in components
- UI Components:
- Import shadcn components from
@kandev/ui, NOT@/components/ui/* - Always prefer native shadcn components over custom implementations
- Check
apps/packages/ui/src/for available components (pagination, table, dialog, etc.) - For data tables, use
@kandev/ui/tablewith TanStack Table; use shadcn Pagination components - Only create custom components when shadcn doesn't provide what's needed
- Import shadcn components from
- Components: <200 lines, extract to domain components, composition over props
- Hooks: Domain-organized in
hooks/domains/, encapsulate subscription + selection - WS: Use subscription hooks only; client auto-deduplicates
- Interactivity: All buttons and links with actions must have
cursor-pointerclass
Plan Implementation
- After implementing a plan, run
make fmtfirst to format code, then runmake typecheck test lintto verify the changes. Formatting must come first because formatters may split lines, which can trigger complexity linter warnings.
Observability
- In dev mode (
KANDEV_MOCK_AGENT=trueordebug.pprofEnabled),/debug/varsexposes the stdlib expvar handler. Office provider-routing metrics live underrouting_*(route attempts, fallbacks, parked runs, provider degraded/recovered counters). The metrics are also still emitted as structuredrouting.metric.*zap logs for human debugging.
GitHub Operations
Skills use gh CLI by default. If a gh command fails (not installed, not authenticated, etc.), use whatever GitHub tools are available in the environment (MCP GitHub tools, API tools, etc.) to accomplish the same operation. The goal is the same — the tool may differ.
Third-party integrations
Jira and Linear are the model (per-workspace credentials, 90s auth-health poller via internal/integrations/healthpoll, settings page with status banner). New integrations should reuse the shared shapes rather than copying either. Full layout, file conventions, and Jira-vs-Linear divergence notes in the /add-integration skill — load it when scaffolding a new integration.
Runtime profiles (prod / dev / e2e)
profiles.yaml at the repo root is the single source of truth for env-driven runtime defaults — feature flags, mock providers (agent / GitHub / Jira / Linear), debug switches, and e2e tuning knobs. The backend embeds it (//go:embed via apps/backend/internal/profiles/) and at startup calls profiles.ApplyProfile() to write the matching profile's env vars onto its own process, only when each var is not already set — so launchers, shells, and per-spec overrides still win.
Profile selection: KANDEV_E2E_MOCK=true → e2e, KANDEV_DEBUG_DEV_MODE=true → dev, otherwise prod. apps/cli/src/dev.ts and apps/web/e2e/fixtures/backend.ts set only the selector — they no longer hardcode the underlying values.
To flip a feature on for every user: change its prod: to "true" in profiles.yaml. To add a new feature flag: 1 line in profiles.yaml + 1 FeaturesConfig field + the gate at the call site + the frontend additions (FeatureFlags type, useFeature checks, notFound() from a server-side layout). Full pattern in docs/decisions/0007-runtime-feature-flags.md.
Maintaining This File
This file is read by AI coding agents (Claude Code via CLAUDE.md symlink, Codex via AGENTS.md). If your changes make any section of this file outdated or inaccurate - e.g., you add/remove/rename packages, change architectural patterns, add new adapters, modify store slices, or change conventions - update the relevant sections of this file as part of the same PR. Keep descriptions concise and factual. Do not add speculative or aspirational content.
Last Updated: 2026-05-16