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# CLAUDE.md
Guidance for Claude Code. Contains only what cannot be derived by reading the code —
decisions, rationale, prohibitions, and open debt. Keep this file concise.
---
## Core Contract (non-negotiable)
1. **Zero mandatory dependencies** — `pip install hushclaw` on stock Python 3.11 must work. Optional features live behind `extras_require`. No non-stdlib import at module level outside `providers/anthropic_raw.py`, `providers/openai_raw.py`, and test files.
2. **`server_impl.py` is transport only** — HTTP/WebSocket dispatch. Zero business logic in `_handle_*` methods; each should delegate to a domain module.
3. **Tools are framework-agnostic** — no tool module may import from `hushclaw.*` except `tools.base`. All runtime dependencies arrive via parameter injection (`_memory_store`, `_config`, `_gateway`, `_session_id`, `_loop`, `_confirm_fn`, `_output_dir`, …).
4. **`event_stream()` is the primary API** — `run()` is a convenience wrapper.
5. **Compaction is never disabled** — fix bad summaries by improving compaction, not skipping it.
6. **A conversation's provider tool surface is immutable** — the exact schema JSON is frozen in `session_tool_surfaces`. New or changed skills become visible to new sessions; never mutate an active session's tool definitions because this invalidates provider prompt caches.
---
## Design Principles
### 1. Resilience First
Error taxonomy before recovery decisions (`hushclaw/core/errors.py`):
- `AUTH_FAILURE` → surface, stop | `RATE_LIMIT` → backoff + credential rotation
- `CONTEXT_TOO_LONG` → compact + retry | `TRANSIENT` → retry ×3 | `FATAL` → abort turn
Graceful degradation: vector search fails → BM25 only; browser unavailable → tools silently absent; trajectory write fails → log + continue. Never surface these to the user.
### 2. Safety by Design
- `_confirm_fn=None` blocks all dangerous tools by default (server path). REPL injects an interactive prompt.
- Subagent depth cap: parent (0) → child (1); children cannot re-delegate.
- SSRF protection in `fetch_url`: RFC 1918, loopback, link-local, cloud metadata IPs blocked before any socket opens (`tools/builtins/web_tools.py`).
- Skill sandboxing is **partial** — pip installs run unaudited in the same venv.
Priority when principles conflict: **Safety > Modularity > Token Economy > Observability**.
### 3. Token Economy
System prompt is a `(stable_prefix, dynamic_suffix)` tuple:
- `stable_prefix` — role + AGENTS.md + SOUL.md. KV-cache eligible (never changes mid-session).
- `dynamic_suffix` — today's date + USER.md + score-gated recalled memories (rebuilt every query).
Budgets are explicit (`context/policy.py`): `stable_budget`, `dynamic_budget`, `history_budget`, `memory_max_tokens`. No section silently crowds out another.
Memory recall: FTS shortcut (skip vector if BM25 ≥ 0.8) → score-gate → budget-cap → 30s session cache.
Skill loading is progressive: listing only → full SKILL.md → referenced files. Never load all skills at once.
Tool loading is also progressive: common schemas are eager; long-tail tools are
discovered with `tool_search` and invoked through `tool_call`. The bridge resolves
to the underlying `ToolRuntime` call before policy/audit/verification, while the
provider history retains the stable wrapper identity.
### 4. Modularity via Composition
Four extension seams:
1. `LLMProvider.complete() → LLMResponse` — single-method contract, one file per provider.
2. `ContextEngine` ABC (`assemble`, `compact`, `after_turn`) — swap without touching AgentLoop.
3. `@tool` decorator — only registration mechanism.
4. Parameter-name injection — tools declare what they need by naming parameters.
**Parallel tool execution is implemented**: `ToolDefinition.parallel_safe=True` marks read-only tools. `event_stream()` in `loop.py` splits tool calls into dedup / parallel (`asyncio.gather`) / serial groups. Marked tools: `recall`, `search_notes`, `get_time`, `platform_info`, `read_file`, `list_dir`, `make_download_url`, `fetch_url`, `jina_read`.
### 5. Streaming and Observability
Event stream contract: `chunk`, `tool_call`, `tool_result`, `compaction`, `round_info`, `done`, `error`, `session`. Adding types is fine; removing/renaming is a breaking change.
Token accounting is first-class — persisted per turn and session to the `turns` table.
Every completed assistant event carries a `perf` envelope. SQLite triggers
project it into `run_metrics` for diagnostics; `events` remains authoritative.
### 6. User Modeling & Learning
- `USER.md` — user profile (communication style, workflow, recurring goals). Injected into `dynamic_suffix`, distinct from `MEMORY.md` (world facts).
- Learning loop (`learning/controller.py`): captures tool traces per turn, runs `reflect_trace()`, persists to `reflections` + `skill_outcomes` tables. Quality score derived from trace: corrections → 0.0, errors → 0.6, clean → 1.0. Auto-patches single editable skills on strong signals.
- Memory creativity defaults enabled: `memory_decay_rate=0.002` (half-life ~350 days), `retrieval_temperature=0.1`.
---
## Web Access Stack
`fetch_url` priority: **curl_cffi** (Chrome TLS/h2 fingerprint, auto-installed) → **urllib fallback**.
Both paths: SSRF gate → request → CF challenge detection → decompress (gzip/deflate/brotli).
Proxy: reads `HTTP_PROXY` / `HTTPS_PROXY` / `ALL_PROXY` env vars; also accepts `proxies=` param.
Full web access priority for the LLM to use as a decision guide:
1. `fetch_url` — lightweight, TLS fingerprint, cookie jar, no JS rendering
2. `jina_read` — Jina proxy renders JS, returns clean markdown (200 req/day free)
3. `browser_navigate` + suite — full Playwright + playwright-stealth, handles Turnstile, login flows
4. `browser_connect_user_chrome` — CDP to user's existing Chrome (for already-logged-in sites)
---
## Skill Tiers
Four tiers, ascending priority (later overrides earlier):
| Tier | Directory | Who writes |
|------|-----------|------------|
| `builtin` | `skills/builtins/` (package) | Code; read-only |
| `system` | `_data_dir()/skills/` | Admin pre-install; shared |
| `user` | `_data_dir()/user-skills/` | WebUI install flow |
| `workspace` | `workspace/.hushclaw/skills/` | Per-project manual |
`user_skill_dir` is created on server startup (not lazily).
---
## Architecture
```
CLI / WebSocket
└─ Gateway # multi-agent routing, session affinity
└─ AgentPool # per-agent, per-session AgentLoop instances
└─ AgentLoop # ReAct event loop (loop.py)
├─ ContextEngine.assemble() # (stable_prefix, dynamic_suffix)
├─ ToolSurfaceSnapshot # session-frozen eager + discovery schemas
├─ ContextEngine.compact() # when history_budget exceeded
├─ LLMProvider.complete() # pluggable, single-method contract
├─ ToolRuntime.execute() # policy/audit → injection + dispatch
├─ MemoryStore.save_turn() # SQLite + Markdown persistence
├─ ContextEngine.after_turn() # regex fact extraction
└─ LearningController # trace capture → reflection → skill patch
```
Config loading (later overrides earlier):
`defaults.py` → `~/Library/Application Support/hushclaw/hushclaw.toml` → `.hushclaw.toml` → env vars (`HUSHCLAW_*`, `ANTHROPIC_API_KEY`)
---
## Open Debt
Fix these before adding features in the affected area.
| ID | Severity | Description | Location |
|----|----------|-------------|----------|
| DEBT-7 | Low | Numeric budget range checks (`compact_threshold`, `memory_min_score`) not validated | `config/schema.py` — deferred |
### Still Planned (not yet implemented)
- **Credential pool rotation** — multi-key per provider, `fill_first`/`round_robin`/`least_used`. Target: `providers/credential_pool.py`.
- **Context file injection scanning** — scan AGENTS.md/SOUL.md for prompt injection. Target: `context/scanner.py`.
- **Auxiliary task provider chains** — compression/embedding/vision each get independent provider config. Target: `config/schema.py` + `context/engine.py`.
---
## Extension Points
### Adding a provider
1. `hushclaw/providers/my_provider.py` subclassing `LLMProvider` from `providers/base.py`
2. Implement `complete(messages, model, system, tools, max_tokens, **kwargs) → LLMResponse`
3. Handle `system` as `str | tuple[str, str]` for cache-control
4. Register in `providers/registry.py:get_provider()`
5. Add to `PROVIDERS` in `hushclaw/web/app.js`
### Adding a built-in tool
1. `@tool`-decorated function in `tools/builtins/`
2. Only import `from hushclaw.tools.base import tool, ToolResult`
3. Mark `parallel_safe=True` if read-only
4. Add to `ToolsConfig.enabled` in `config/schema.py` for default-on
5. Import module in `ToolRegistry.load_builtins()`
6. Dangerous tools: accept `_confirm_fn=None`; call before mutating state
### Adding a skill package
Git repo with `SKILL.md` + optional `tools/*.py`. Same `@tool` injection contract as built-in tools. Front-matter: `name`, `description`, `tags`, `author`, `version`, `has_tools`.
### File output from tools
Tools that produce files: declare `_output_dir: Path | None = None`. Write to `_output_dir / filename`. Return `{"url": f"/files/{filename}", "path": str(path)}` in result JSON. The executor injects `config.server.upload_dir` automatically.
---
## Commands
```bash
pip install -e . # core only (zero mandatory deps)
pip install -e ".[server]" # + WebSocket server
pip install -e ".[browser]" # + Playwright + playwright-stealth
pip install -e ".[web]" # + curl-cffi + brotlicffi
pip install -e ".[all]" # everything
python -m pytest tests/ -v # full test suite
python -m pytest tests/test_X.py::Class::test -v # single test
hushclaw serve # HTTP + WebSocket on port 8765
hushclaw serve --host 0.0.0.0 # bind all interfaces
make lint # py_compile syntax check
make clean # remove __pycache__, build artifacts
```