Skald-Circle/CLAUDE.md

Skald (project-family) — codebase guide

Rust async web app (Tokio + Axum). Runs as a local chat server with LLM tool-calling and a sub-agent system.

What this repository is

A dedicated fork of Skald, turning a single-user personal agent into a multi-user assistant for a small trusted group — positioned at families, but see the neutrality rule below.

The design lives in blueprint/project-family.md. Read it before any architectural work; its sections are referenced by number (§0.1 neutrality, §5.1 database layout, §11 UserManager, §12 auth schema, §16 LLM privacy tiers, §17 sequencing). The blueprint/ directory is gitignored and not under version control — treat it as the source of truth, and never assume a section says what you remember.

Load-bearing decisions from that document:

• Not upstreamable. Nothing here needs to preserve Skald's schema or be portable back to it.
• Greenfield. No users in production ⇒ no migrations, no backwards compatibility. Tables get restructured, renamed and moved freely; the schema collapses into a single clean baseline v1.
• Dual memory: a private per-user pool plus a shared pool. A user's private space is encrypted so that nobody else — the admin included — can read it through normal use of the system. Never claim "mathematically impossible": the honest promise is transparency plus verifiability (§3).
• Threat model (§2): the adversary is the tempted admin, who owns the box but does not recompile the binary or dump RAM. Do not design against a forensic attacker.
• Roles are data, not enums (§0.1): a roles table binds permission-group, run-context and data-handling attributes. "Children" is a seeded preset row, never a hardcoded type.

The core is domain-neutral — this is a hard rule

"Family" is positioning, not architecture. Schema, engine, API, identifiers and comments must never contain family, household, parent, child or minor. A pivot to teams, small orgs or care settings must not require renaming anything.

Domain concept	Technical primitive
the group	implicit — it is the instance. No group entity. Future multi-group ⇒ tenant / workspace, never family
shared memory	memory/shared
parent / admin	role admin
child / minor	a data-driven role defined by the admin
"the parent reads the child's data"	a generic supervision edge between users

Domain words are allowed only in seed data, preset labels, UI copy and positioning.

Current state

UserManager (§11) exists and works — crates/skald-core/src/users/mod.rs, with real per-user SQLCipher encryption (§4). It is not consumed yet: there is no login, and Runtime still hands every call site the one shared Arc<SqlitePool> on system.db, so chats still land in that file's owner tables. The next step is migrating those call sites to pool_of, and only then deciding where the owner-without-a-user lives (see blueprint §19).

Direction of travel, decided but not yet executed: strip the power-user surface (self-rewriting, arbitrary shell, dev-agent suite, ticket system) and move to a binary-first layout — the app is built once and run from a compiled binary, not executed from its own source tree.

Workspace layout

The application core is the skald-core crate; the binaries are shells around it.

Crate	Role
crates/skald-core/	Storage, identity, crypto, LLM stack, tools, MCP, sessions. Knows nothing about what runs it: no Tauri, no HTTP server, and no concrete plugin crate — PluginManager only ever sees Arc<dyn Plugin> from core-api
skald (root, src/)	The server shell: main.rs, the Axum frontend/, the Tauri desktop/, config.rs. Constructs the plugin list and hands it to Skald::new
crates/core-api/	The contracts both sides share: Plugin, Tool, event buses, provider types

Two rules keep the boundary real, and both are enforced by the compiler:

• The core never names a plugin. A plugin contributes tools through Plugin::tools(self: Arc<Self>) — the sibling of http_router() — so nothing in the core has to downcast to a concrete type. Naming one would drag every plugin in the tree into the core, including a C build via plugin-transcribe-whisper-local.
• The core never learns about the process shell. The restart tool defaults to the supervisor protocol (exit(-1)); a shell with different needs installs tools::restart::set_restart_handler at startup. The Tauri shell installs teardown-and-respawn there. This is why skald-core has no desktop feature.

skald_core::boot emits curated startup lines on the boot tracing target; each shell decides how to render them (src/boot_format.rs here). The core says what happened, never how it looks.

Key modules

Path	Role
src/main.rs	Thin entry point: tracing → Skald::new → WebFrontend::start → shutdown. Branches on the desktop feature: under --features desktop enters desktop::run() (Tauri event loop) instead of blocking on a tokio runtime. Exposes run_backend() / shutdown_backend() shared by both entry points
src/desktop/mod.rs	Tauri shell — only compiled under --features desktop. Builds the system-tray icon + menu (Open / Quit), creates the main WebviewWindow (URL = http://127.0.0.1:{config.port}), spawns the backend on Tauri's shared tokio runtime, handles graceful shutdown. Holds the OnceLock<AppHandle>, and installs the core's restart handler. See docs/desktop.md
crates/skald-core/src/skald/	Skald — headless application core. mod.rs (struct + staged new() / shutdown()), runtime.rs (cross-cutting Runtime context), bundles.rs (8 domain bundles + build()), wiring.rs (wire() + spawn_background()), supervisor.rs (TaskSupervisor), accessors.rs (per-manager accessor facade — the API surface the frontend uses)
crates/skald-core/src/session/handler/	Core LLM loop — mod.rs, llm_loop.rs (run_agent_turn), agent_dispatch.rs, dispatcher.rs, approval.rs, resume.rs, messages.rs, config.rs, interface_tools.rs
crates/skald-core/src/session/manager.rs	Creates/retrieves ChatSessionHandler per session
crates/skald-core/src/chat_hub/	ChatHub: broadcast events to all connected WS clients
crates/skald-core/src/chat_event_bus.rs	Global async bus for cross-session events
crates/skald-core/src/agents.rs	Discovers agents from agents/*/, loads meta + system prompt
crates/skald-core/src/tools/	Built-in tools: exec, restart, list_agents, fs/*, notify, ast_outline, image_generate, MCP tools, plugin tools, cron tools
crates/skald-core/src/tool_catalog.rs	ToolCatalog: unified tool listing façade (wraps ToolRegistry + McpManager)
crates/skald-core/src/events.rs	ServerEvent enum streamed over WebSocket to the frontend
crates/skald-core/src/db/	sqlx SQLite — see below
crates/skald-core/src/users/	UserManager (§11): user directory CRUD on system.db, credential check, and the map userid → SqlitePool of unlocked databases. The pool is the unlock token — its connect options carry the DEK as SQLCipher's raw key, so an open pool means the key is in RAM (§9) and dropping it re-locks. Knows nothing about cookies: whatever maps an HTTP session to a user id sits above it
crates/skald-core/src/crypto/	Envelope encryption (§4/§5.1). A random 256-bit DEK encrypts {userid}.db; users.database_password holds it sealed with AES-256-GCM under Argon2id(password, salt). The AEAD tag is the password verifier — one derivation both authenticates and yields the key, and no second hash sits in the admin-readable DB. Cleartext users store the Argon2id output directly, compared constant-time. Argon2 runs in spawn_blocking behind a 2-permit semaphore (256 MiB per derivation)
src/config.rs	Loads config.yml; LLM clients, strength/use_cases, data root. Also hosts bootstrap_data_dir() — under the desktop feature, relocates the process cwd to a per-user data dir when running inside a .app bundle (no-op in dev mode and headless mode)
crates/skald-core/src/mcp/	MCP client manager (connects to external MCP servers)
crates/skald-core/src/plugin/	Plugin system: discovery, enable/disable, tool registration
crates/skald-core/src/cron/	Scheduled job runner
crates/skald-core/src/compactor.rs	Context compaction (summarises history when token budget exceeded)
crates/skald-core/src/approval/	Approval rules engine
crates/skald-core/src/clarification/	ClarificationManager: background-session question/answer
crates/skald-core/src/elicitation/	ElicitationManager + bridge: MCP server-initiated input (elicitation/create), surfaced in the Inbox; secrets never logged/persisted
crates/skald-core/src/inbox.rs	Inbox: unified façade for pending approvals + clarifications + elicitations (wraps ApprovalManager, ClarificationManager, ElicitationManager)
crates/skald-core/src/llm/	LLM client abstraction (OpenAI-compat, Anthropic, Ollama…)
crates/skald-core/src/transcribe/	Transcription providers
crates/skald-core/src/image_generate/	Image generation providers
crates/skald-core/src/memory/	Agent memory tools
src/frontend/mod.rs	WebFrontend: wires router_factory, starts plugins, runs Axum
src/frontend/server.rs	Axum router, static file serving
src/frontend/api/	HTTP + WebSocket handlers — State<Arc<Skald>>
web/components/	Lit web components (see below)

DB tables (sqlx SQLite)

database/system.db — the path is a constant (core::db::SYSTEM_DB_PATH), not configurable. init_system_pool creates the directory; SQLite only creates the file. Per-user files are database/{userid}.db, created by UserManager::register_user and encrypted with SQLCipher.

The schema is split into two buckets (§5.1), and the split is the point:

• create_registry_tables — instance-wide, readable without any user key: users, llm_providers, llm_models, transcribe_models, tts_models, image_generate_models, plugins, approval_rules, tool_permission_groups, config, known_tools, llm_requests.
• create_owner_tables — one owner's content, identical schema in every file that has it: chat_sessions, chat_sessions_stack, chat_history, chat_llm_tools, chat_summaries, session_scratchpad, session_mcp_grants, stack_mcp_grants, scheduled_jobs, job_runs, mcp_servers, mcp_events, sources, secrets, projects, project_tickets.

No foreign key in the owner bucket may point at a registry table. SQLite cannot enforce a key across files, not even through ATTACH, and sqlx turns on PRAGMA foreign_keys: the CREATE TABLE succeeds and every INSERT fails. db::tests::owner_tables_stand_alone_with_foreign_keys_on enforces this by running the owner schema against a database holding nothing else, then inserting a row into each table. Two keys crossed and were fixed: chat_history.model_db_id (dropped — write-only, and llm_requests.model_name already records the model) and project_tickets.job_id (fixed by moving projects/project_tickets into the owner bucket).

system.db currently gets both bucket functions, because nothing has migrated to per-user pools yet. That is transitional.

users (crates/skald-core/src/db/users.rs) holds the directory plus auth material. It lives in the system DB, which the box owner can read, so it must never store anything that derives a user's key. Credentials is an enum mirroring the table's CHECK: an encrypted user carries a wrapped DEK (whose AEAD tag is the password verifier — hence no password_hash); a cleartext user carries an ordinary verifier, or none. User is deliberately not Serialize and its Debug redacts key material — use User::summary() for anything leaving the process. role_id has no foreign key yet: sqlx enables PRAGMA foreign_keys, so referencing the not-yet-existing roles table would fail every insert.

Sub-agent system

• Synchronous sub-agents (execute_task mode=sync / execute_subtask) are not plain Tools — they are intercepted in run_agent_turn before registry dispatch.
• dispatch_sub_agent (in agent_dispatch.rs) creates a child chat_sessions_stack row and runs run_agent_turn recursively in the same task, holding the same processing lock and sharing the same cancellation token. The child's result string becomes the parent tool call's result (completion lives in one place — the run_agent_turn tool-result match); then it terminates the child frame. There is no task-spawn / WaitingChild / resume cascade for the sync path.
• Max recursion depth: MAX_AGENT_DEPTH = 5.
• Parallel batches: when a single assistant response emits ≥2 sync sub-agent calls and nothing else, run_agent_turn fans them out concurrently via handle_sub_agent_batch (bounded by max_parallel_subagents, default 4). Ordering is preserved by allocating every chat_llm_tools row up front in call order (the LLM reconstructs results by row id), then recording outcomes back in call order; only the middle dispatch is concurrent. Any other shape (a lone call, or a mix with regular tools) keeps the strictly sequential handle_tool_call loop — the two paths share the same lower-level seams. Siblings share the session's scratchpad blackboard (session-keyed): concurrent writes to the same key are last-writer-wins by design.
• Restart recovery of a parallel batch is intentionally lossy (single-user app): resume_turn first calls reap_interrupted_parallel_batches, which detects a batch by ≥2 active chat_sessions_stack frames at the same depth (impossible for a linear stack), fails their spawning tool calls and terminates the frames, then lets the normal linear cascade resume the parent. A lone interrupted sub-agent is untouched and still recovers via the cascade.
• Client resolution order: args.client → meta.json client → AUTO selection by scope/strength.
• The parent's resolved client is NOT inherited. Passing a concrete model name to resolve() bypasses strength/scope checks; sub-agents always auto-select unless overridden explicitly.
• list_agents is a plain tool; returns JSON excluding main.
• resume_turn (+ its cascade) is kept only for: app-restart recovery of an active child stack, async task result injection (inject_async_result), and the WS resume message — not for the normal sync dispatch.

Cancellation (stop)

• Each turn has a CancellationToken (tokio_util). handle_message mints a fresh one per user message and stores it in current_cancel; resume_turn mints one per resume. A clone is threaded by value through the whole (recursive) call tree — never re-read from the field mid-turn — so a /stop is sticky across sub-agent recursion.
• cancel() cancels the stored token. It is checked at each round boundary and before each tool call, wrapped around the in-flight LLM call (tokio::select!, aborting the request), and wrapped around execute_cmd (drops the future → kill_on_drop kills the shell process). Parent and child share the token, so a cancelled child stops the parent by construction.

Approval gate

The rule engine ApprovalManager::check returns Allow/Deny/Require per tool call (default rules seeded on first boot; the catch-all * require @999999 gates anything not explicitly allowed — e.g. execute_cmd, restart, execute_task, writes outside whitelisted paths). A Require registers a oneshot in the in-memory pending map keyed by request_id and emits an approval event over WS.

Resolution is source-agnostic: the WS + Inbox paths resolve by request_id; the inline chat card resolves by the durable tool_call_id via POST /api/tools/:tool_call_id/resolve (resolve_tool in src/frontend/api/sessions.rs), which derives the owning session from the tool call's own stack row — never a hardcoded source. Live pending cards fire the oneshot; post-restart they execute directly on the owning session. See docs/approval/.

Tool visibility in the Security-groups UI (GET /api/approval/tools): tools injected outside the ToolRegistry (interface/plugin/provider tools) would otherwise be un-configurable. ToolCatalog::list_all() covers registry tools + a static synthetic_tools() list of core interface tools; everything else is captured by crates/skald-core/src/tool_discovery.rs (ToolDiscovery), which taps all_tool_defs() in llm_loop.rs each round and upserts every offered tool into the known_tools table (in-memory seen-set guard → background DB write). list_tools merges known_tools (deduped, category: "dynamic") so any tool offered at least once becomes gate-able. Drift-proof by construction; core never hardcodes plugin tool names.

Restart

restart no longer rebuilds anything — neither mode compiles.

• Headless (default): no handler installed, so restart calls libc::_exit(-1) (= exit code 255); run.sh re-executes the same binary by path.
• Desktop (--features desktop): the Tauri shell installs a handler via tools::restart::set_restart_handler — cleanup + respawn of the bundled binary + exit(0). The core does not know Tauri exists.

Use it to pick up config.yml / database changes, which are only read at startup. To load new code: ./build.sh, then restart — the supervisor picks up the new binary on the next loop, since build.sh installs it with an atomic rename.

run.bat is still stale (cargo run) and must be fixed.

Build & run

./build.sh      # cargo build --release → bin/skald (atomic install)
./build.sh -d   # debug profile; extra args are forwarded to cargo
./run.sh        # supervisor loop over the pre-built binary — never compiles

run.sh resolves the binary as $SKALD_BIN → bin/skald → target/release/skald, and warns when sources are newer than the binary. Exit 0 stops the loop, 255 re-executes, anything else propagates.

Tracing filter: RUST_LOG=skald=debug,info

Desktop bundle (Tauri)

cargo run --features desktop          # dev: real window + tray, no bundle
cargo tauri build --features desktop  # release bundle: .app / .exe / .AppImage

Requires cargo install tauri-cli --version "^2". The desktop feature is default-off.

Adding an agent

Create agents/<id>/meta.json and agents/<id>/AGENT.md. The agent is discovered at runtime (no restart needed for prompt edits). Optionally set "client": "<name>" in meta.json to pin a specific LLM.

Documentation

The docs/ directory is ignored for now — do not read it, reference it, or update it. It is slated for removal.

Config

Copy default.config.yaml → config.yml. Never commit config.yml (contains API keys).

Python environment

All Python scripts (MCP servers, setup scripts) use a local virtualenv at .venv/ in the project root.

run.sh creates it automatically on first launch (using uv if available, otherwise python3 -m venv) and installs requirements.txt. It then prepends .venv/bin to PATH before starting the app, so every child process — MCP server launches, execute_cmd shell calls — resolves python3 to the venv automatically. No manual activation needed. Python is optional: if neither uv nor python3 is found, the app starts normally and only Python-based MCP servers will be unavailable.

To add a Python dependency: add it to requirements.txt. It will be installed on the next ./run.sh invocation if .venv does not yet exist — or run uv pip install -r requirements.txt manually.

Frontend components (web/components/)

All extend LightElement from web/lib/base.js (Lit). ChatSession (web/lib/chat-session.js) is the shared base for WS-connected chat UIs.

File	Element	Notes
copilot.js	<app-copilot>	Desktop copilot (_wsSource='web'); composer input with model pill, auto-resize textarea
shared/chat-page.js	<chat-page>	Mobile chat (_wsSource='mobile')
copilot-render.js	(helpers)	renderMsg, renderTool, renderDiff, etc. — shared by copilot and chat-page
sidebar.js	<app-sidebar>	Nav sidebar; polls /api/inbox every 10 s for badge
topbar.js	<app-topbar>	Top nav bar
home-page.js	<home-page>	Landing / dashboard
shared/file-viewer-base.js	FileViewerBase (base)	Shared file-viewer engine (fetch, kind detection, markdown/PDF/SVG/LaTeX, watcher, _renderBody); driven by _show/_hide. Extended by desktop + mobile
file-viewer-page.js	<file-viewer-page>	Desktop file viewer: FileViewerBase + hash routing via window.openFile(path) → #file_viewer?path=...
shared/file-viewer-mobile.js	<mobile-file-viewer-page>	Mobile file viewer: FileViewerBase + prop-driven (visible/path), full-screen with back button
agents.js	<agents-page>	Agent discovery and config
agent-inbox.js	<agent-inbox-page>	Pending approvals + clarifications from background sessions
approval-rules.js	<approval-rules-page>	Approval rule management
cron-jobs.js	<cron-jobs-page>	Scheduled job management
llm-providers.js	<llm-providers-page>	LLM provider management
models-hub.js	<models-hub-page>	Models hub landing (LLM / Transcription / Image)
models-llm.js	<models-llm-section>	LLM model CRUD + drag-and-drop priority
models-transcribe.js	<models-transcribe-section>	Transcription model CRUD
models-image.js	<models-image-section>	Image generation model CRUD
mobile-app.js	<mobile-app>	Mobile app shell