Commit Graph

36 Commits

Author SHA1 Message Date
Tianyi Cui
4c8c1da8b3 feat: generate module dependency graph with freshness gate
Add scripts/gen-module-graph.ts, which derives the inter-package
dependency graph from each package's @deepseek-ai/dsh-* peerDependencies
and renders docs/module-graph.md (a GitHub-native Mermaid graph plus a
dependency table). Output is deterministic so a regenerate-and-diff
check is stable.

Wire a freshness gate the same way doc-sync is wired (ADR 0007: hooks
and CI run the same package.json scripts): verify-module-graph runs in
pre-push (lefthook) and as a CI step. It fails if the committed file
drifts from what the generator would produce.
2026-06-16 21:00:24 +08:00
Tianyi Cui
49e74ed8d0 docs: add ADR 0016 for the pnpm migration
Records the why behind the Yarn 4 → pnpm move (PR #39): ecosystem
alignment, strict-linker phantom-dependency safety, build-script
allowlisting, and the package-manager-independent constraints script.
Captures migration-time install benchmarks and notes the gate suite
passes unchanged on pnpm.
2026-06-16 15:55:21 +08:00
07akioni
dabc2ff411 feat: migrate to pnpm 2026-06-16 14:55:37 +08:00
Tianyi Cui
247c408e75 Merge pull request #21 from deepseek-ai/fix/agent-loop-step-start-order
fix(agent-loop): append step/start before emitting agent/step-start
2026-06-15 22:08:52 +08:00
Tianyi Cui
a1eea4d36e docs: note multi-language Code Mode backends in RFC 012
Clarify that the CodeRuntime seam can host backends differing by
language/runtime, not just trust level — e.g. an AssemblyScript/WASM
backend (naturally sandboxed) and a Python backend over CPython or a
more controllable/embeddable interpreter. Note the execution contract
is language-agnostic while SDK codegen/prompt presentation is per-
language, and add these backends to the deferred follow-up list.
2026-06-15 08:37:45 +08:00
Tianyi Cui
1b7c376aec docs: address second-round PR review on RFC 012 (alternatives, framing)
- Add an Alternatives section comparing Code Mode against the narrower
  result-elision/summarization route over native tool-calling (solves
  context-bloat but not composition/round-trips) and against parallel native
  dispatch (a core-loop change that still lacks composition); states why
  Code Mode is chosen and why the new code-execution surface is the price.
- Fix the Problem-section framing: it said the model "can run independent
  calls concurrently," which contradicted the serialize-by-default decision.
  Reworded to "express fan-out, initially serialized until concurrency-safety
  metadata exists" — early win is composition + fewer round-trips, not parallelism.
2026-06-15 01:46:26 +08:00
Tianyi Cui
6d9934103d docs: address PR review on RFC 012 (concurrency, vm guard, prompt budget)
- Concurrency: change from "may serialize" to mandatory serialize-by-default
  via a per-run dispatch queue in the SDK bindings, with a non-overlap test as
  a hard acceptance criterion (the binding shape otherwise makes Promise.all
  dispatch concurrently before the tool contract has concurrency-safety metadata).
- node:vm guard: make it enforceable, not a README warning — CodeRuntime exposes
  safe:boolean, the VM stub throws unless constructed { unsafe:true }, and
  code-mode refuses to register run_code over an unsafe runtime unless separately
  acknowledged (allowUnsafeRuntime); refusal path is tested.
- Prompt budget: drop the "zero prompt tokens" claim (the SDK .d.ts is injected
  into the system prompt, so types do consume context) and add the explicit
  budget/caching tradeoff — Code Mode's saving is on output/round-trips, not the
  input-side tool description.
2026-06-15 01:39:21 +08:00
Tianyi Cui
1cc6e1caf7 docs: add RFC 012 (optional Code Mode for all tools)
Proposes an optional Code Mode where the model writes a TypeScript program
against a generated SDK wrapping every registered tool, instead of emitting
one native tool-call per step. Implemented Cordis-style as a capability-seam
trio (code-runtime interface / code-runtime-vm node:vm reference stub /
code-mode consumer plugin) with zero core-package changes; the hardened
execution substrate is deferred to a follow-up RFC.
2026-06-15 01:20:09 +08:00
Tianyi Cui
9d5b3ab832 fix(agent-loop): append step/start before emitting agent/step-start (P1-6)
Every loop boundary appends the session event before emitting the Cordis
event (ADR 0003's append-before-emit rule) — except step/start, which was
inverted. A listener on agent/step-start that inspected session.events could
not see the step it was just told had started.

- Swap the two lines so session.append('step/start') precedes the emit.
- Fix the two stale pseudo-code copies (the runLoop JSDoc STEP-loop block and
  docs/architecture.md) so neither shows step-start emitted before the append.
- Regression test: a step-start listener observes the matching step/start
  event already at the tail of session.events. Verified the test fails on the
  pre-fix (emit-first) order.
2026-06-14 23:18:41 +08:00
Tianyi Cui
de73afbe39 docs: resolve self-consistency follow-ups on RFCs 009-010
- 009: the crash-tail "overwrite" contradicted the append-only contract.
  Name it explicitly as a one-time truncation-repair (ftruncate+fsync to
  the last complete turn/end byte offset) that removes only the
  never-committed crash tail; committed events are never rewritten.
  Qualify the append/impl/ADR wording to match.
- 010: remove the remaining concrete-loop references — the session/new
  and session/load table rows now point at the dsh-agent create/resume
  factory, and the Risks disposal line uses the interface-level settle
  signal (agent/status) instead of LoopAgent-only agent.done.
2026-06-14 21:57:59 +08:00
Tianyi Cui
64ce7caedc docs: address review on RFCs 009-011
Resolve the inline review feedback on PR #18 (all verified against the
codebase, the published @agentclientprotocol/sdk@0.25.1 tarball, and
Cordis fiber semantics):

- 009: dsh-session owns SessionMeta (persistence re-exports) to avoid a
  package cycle; split mutable summary into a sidecar so the event log
  stays append-only and list/load can return it; pick one load-repair
  rule (resume from the last complete turn/end, overwrite the orphan).
- 010: SDK has a zod peer dep + runtime zod/v4 import (drop "zero runtime
  deps"); session/new needs a create seam taking {sessionId, meta};
  propose an abstract create/resume factory on dsh-agent so the bridge
  depends on the interface not the loop, and observe agent/status for
  quiescence since agent.done is LoopAgent-only; add the explicit
  TurnEndReason -> ACP StopReason wire mapping + test; reject non-empty
  additionalDirectories for the MVP; remove the EOF blank line.
- 011: ctx.extend() does not create a disposable fiber — use a real
  per-session disposer scope.
2026-06-14 21:43:16 +08:00
Tianyi Cui
a44f7f3486 docs: add RFCs 009-011 (session persistence + ACP support)
Three proposal documents, numbered in dependency order:

- RFC 009: an abstract, append-only, event-based SessionPersistence
  service over the existing SessionEvent log (no parallel persisted
  type), a JSONL impl, a SessionMeta header seam, and an async
  AgentLoop.resume path. Design informed by Codex/Claude Code/
  opencode/pi. Core design point; unblocks resume + ACP session/load.
- RFC 010: ACP (Agent Client Protocol) support as a dsh-acp
  client-driver plugin on @agentclientprotocol/sdk, mapping ACP onto
  the agent/* events and the tools/execute permission seam. Builds on
  009 for session/load; single active session.
- RFC 011: multiplex concurrent ACP sessions over one connection
  (bridge-layer change; downstream of 010).
2026-06-14 21:14:51 +08:00
Tianyi Cui
7586caf2dd docs: clarify Node CI matrix 2026-06-14 11:28:00 +08:00
Tianyi Cui
f2524e9c45 docs: sync dev guide with stacked gates 2026-06-14 10:52:46 +08:00
Tianyi Cui
c3a3b6ae41 docs: clarify CI and hook gates 2026-06-14 10:50:10 +08:00
Tianyi Cui
91d7515fd8 docs: add development setup guide 2026-06-14 10:50:10 +08:00
Tianyi Cui
58627f075d Merge branch 'feat/rfc006-doc-sync' into feat/rfc005-error-taxonomy 2026-06-14 10:44:29 +08:00
Tianyi Cui
fa7d1df6f2 build: run doc-sync gates in the local pre-push hook too
The doc-sync gates were CI-only, so the AGENTS.md doc-sync promise could be
missed locally until after push. Add a shared `doc-sync` package.json script
(doc-typecheck + verify-event-taxonomy) wired into the lefthook pre-push job,
and point the CI step at the same script — one source of truth per ADR 0007.
Addresses PR review finding.
2026-06-14 10:40:20 +08:00
Tianyi Cui
825b57aff9 feat(llm): structured error taxonomy with a shared HarnessError base (RFC 005 pt 2)
Introduce HarnessError in dsh-llm (the leaf package): a stable machine-routable
code distinct from the message, cause chaining, name from the subclass, plus
isHarnessError. LlmError, ToolArgsError, and InvariantError now extend it.

Tool failures carry the structure end-to-end: ToolExecutionResult gains
error: { name, code } (populated from a thrown HarnessError), and the loop
forwards it onto the tool/result session event (which gained the same optional
field) for retry/sandbox plugins and replay. The loop's toError wraps non-Error
throws in a HarnessError(code: UNKNOWN, cause) instead of a bare Error.

Landed last and in isolation so it's a pure upgrade over the plain Error+code
the earlier PRs used — independently revertible. Graduates RFC 005 pt 2 ->
ADR 0015; RFC 005 now fully implemented.
2026-06-14 01:07:28 +08:00
Tianyi Cui
6a528be569 build: doc-sync gates — typecheck doc code blocks + verify event taxonomy (RFC 006 pts 1-2)
Two tsx CI gates make doc/code drift fail fast:
- doc-typecheck extracts every fenced ts block from README/docs/package READMEs,
  compiles them with tsc --noEmit against a temp project (vendor->lib, harness->src
  paths from tsconfig.typecheck.json), and fails on errors. Deliberate sketches opt
  out with ```ts ignore-check; the opt-out ratio is reported and capped.
- verify-event-taxonomy asserts the docs/architecture.md taxonomy table names
  exactly the events declared in the interface Events blocks. This surfaced three
  events the table had been missing (tools/change, llm/adapter-change,
  system-prompt/change), now added.

Doc snippets made compilable with stub imports/declares (1 genuine sketch ignored).
Wired into CI after typecheck. API reports (RFC 006 pt 3) deferred. Graduates RFC
006 pts 1-2 -> ADR 0014.
2026-06-14 00:47:38 +08:00
Tianyi Cui
2f6d3b8539 test: property-based tests for protocol-shaped code (RFC 001)
Adds fast-check + one tests/properties.spec.ts per protocol-shaped package
(llm/BlockAssembler, session, tools/schema DSL, agent-loop scheduling). The
tools suite includes the RFC 001<->005 composition property (generated args
satisfying a spec pass validateArgs), closing the validator/InferArgs drift
risk from ADR 0011. Loop properties are deterministic (settle on agent/status,
no sleeps).

The BlockAssembler suite found a real bug on first run: a duplicate block-end
at the same index overwrote an already-flushed block, so the streamed prefix
disagreed with final blocks(). Fixed (first close wins, matching the existing
straggler rule) + regression test. Graduates RFC 001 -> ADR 0013.
2026-06-14 00:06:25 +08:00
Tianyi Cui
89e63f1436 fix(invariants): address Codex review of dev invariants (PR 2)
- HMR state soundness: inject sessions, rebuild per-session trace by replaying
  each existing session's log at (re-)apply, so a reload mid-turn no longer
  falsely rejects the next event
- tighten nesting: turn/end rejects an open step; step/start rejects an open
  step; chunk/message/tool events must name the open turn+step; pendingCalls
  clears at step/end so a cross-step tool/result can't satisfy a stale call
- drop the default export (it stripped the inject metadata when loaded by
  name; functional plugins expose named exports only — matches tool-bash)
- document deepFreeze's top-down precondition; sync RFC 005/008 bodies to the
  as-implemented decision
2026-06-13 23:50:43 +08:00
Tianyi Cui
11a29fdefe feat(invariants): dev-mode event-contract assertions + session-log freeze (RFC 005 pt 3, RFC 008)
New @deepseek-ai/dsh-invariants plugin (pure listeners, off in prod) asserts
the event taxonomy at runtime — seq monotonicity, turn/step nesting, a
tool/result needs a prior tool/call (NOT the converse), legal agent/status
transitions — and deep-freezes logged event data so mutating history throws.
Seeded sessions are checked + frozen on session/created.

The real RFC 008 fix is always-on: deriveMessages now structured-clones the
content it emits, so the loop's sanctioned request/adapter mutation can no
longer reach back and rewrite the append-only log. The pervasive
DeepReadonly<T> type flip is rejected (compile-only, high-noise, castable) —
recorded in ADR 0012, which folds in RFC 008. Wired into both demos.
2026-06-13 23:25:12 +08:00
Tianyi Cui
11f85b4f88 fix(tools): address Codex review of arg validation (PR 1)
- enum membership now checked uniformly for all SchemaTypes, mirroring the
  converter which emits `enum` regardless of type (was string-only)
- checkValue switch ends in assertNever per the closed-union convention
- sync the adding-a-tool cookbook to the validate-for-you behavior
- soften ADR 0011's property-test claim (RFC 001 not yet landed)
2026-06-13 23:11:48 +08:00
Tianyi Cui
36a30180b8 feat(tools): validate model-generated tool args at the boundary (RFC 005 pt 1)
defineTool now runs validateArgs against the SchemaSpec before execute, so a
malformed model call returns a self-correctable isError result listing the
violations instead of reaching the typed body untyped-in-practice. The
validator mirrors schemaSpecToJsonSchema semantics exactly (required from
required:true only, extra keys allowed, default not applied, object/array
without properties/items only type-checks, enum membership).

tool-bash's hand-rolled type/required checks (carrying the TODO(RFC 005)
stopgap note) are slimmed to just the value constraints the DSL can't express
(non-empty strings, positive timeout). Graduates RFC 005 pt 1 to ADR 0011.
2026-06-13 23:00:42 +08:00
Tianyi Cui
39b3db4b9c docs: accuracy sweep, architecture restructure, two ADRs, review skill
- AGENTS.md Commands: fix typecheck/build descriptions; add lint, lint:fix,
  test:coverage, knip, publint, hygiene (were undocumented).
- Drop the bare `yarn demo` for explicit `demo:echo` + `demo:coding`; update
  README, examples READMEs (and document coding-agent in examples/README).
- New cookbook guide: adding-a-vendored-package.md (the missing "add" half of
  vendor/README's update-only procedure).
- architecture.md: add a table-of-contents and extract the Extension cookbook
  to docs/cookbook/extension-cookbook.md (link-preserving); drop the completed
  "restructure this document" TODO.
- ADR 0009 (capability seams) + 0010 (twin LLM adapters), and a "when to write
  an ADR" standard in adr/README.
- Add a committed dsh-code-review skill under .agents/skills, exposed to Claude
  Code via a tracked .claude/skills symlink (gitignore carve-out).
2026-06-13 22:05:34 +08:00
Tianyi Cui
066f94c7e0 docs: unwrap hard-wrapped Markdown to one line per paragraph
Hard line breaks mid-paragraph make docs harder to edit and diff — a
one-word change reflows and re-diffs the whole paragraph. Reflow all
tracked non-vendor Markdown (plus vendor/AGENTS.md) so each prose
paragraph is a single line; soft-wrapping is the editor's job. Fenced
code, tables, and list structure are preserved (wrapped list items fold
to one line per bullet). Documents the convention in AGENTS.md.
2026-06-13 20:27:04 +08:00
Tianyi Cui
e98c1c5d42 Add examples/coding-agent and the docs cookbook
The first real agent wiring: DeepSeek V4 + the bash tool suite + stdio
chat + JSONL persistence, runnable via yarn demo:coding (reads the
gitignored repo-root .env through process.loadEnvFile).

- examples/coding-agent: cordis.yml wiring both real plugin families
  (llm-deepseek with !!js env secrets; bash-local + tool-bash), a
  bash-only coding system prompt, a max-steps-guard plugin (bounds
  runaway turns via the agent/turn-continuation waterfall — abort()
  from step-end is a no-op by then), and a stdio UI with dimmed
  reasoning and exit-on-idle for piped stdin.
- e2e (yarn test:e2e, key-gated): full-loop.e2e.ts runs a real model
  against the real bash tool; coding-task.e2e.ts is the swebench-style
  smoke — the model fixes a buggy add.js in a temp dir and the test
  re-runs node add.test.js itself rather than trusting the agent.
- docs/cookbook: adding-a-package (the verified checklist),
  adding-a-tool (execute() contract, background pattern, seams),
  adding-an-llm-adapter (protocol obligations, mock-server testing,
  e2e policy). AGENTS.md layout/commands/secrets sections updated;
  architecture.md points at both examples and the cookbook.
- vitest.e2e.config.ts: serialize test files + retry twice — parallel
  e2e files trip the shared internal key's concurrency quota.
- fix: the !js YAML tag spelling in docs/JSDoc is actually !!js
  (js-yaml resolves custom tags under tag:yaml.org,2002:js).
2026-06-13 18:30:50 +08:00
Tianyi Cui
ab19fed77c Add two DeepSeek LLM adapters: dsh-llm-deepseek and dsh-llm-pi-ai
The first real LlmAdapter implementations, shipped as a deliberate pair:
same models and wire protocol, completely different internals, so the
StreamChunk protocol is verified across independent implementations.

- dsh-llm-deepseek: hand-rolled fetch + SSE parser + chunk-translation
  state machine against the official chat-completions format (thinking
  mode via top-level thinking/reasoning_effort; the empty-string
  reasoning_content first chunk; usage attached to the finish chunk or
  trailing; reasoning_content passback on tool-call turns; disjoint
  cache-token accounting).
- dsh-llm-pi-ai: the same endpoint through @earendil-works/pi-ai,
  mapping its event vocabulary (parsed tool arguments, in-stream error
  events, folded reasoning tokens) onto the same chunks.

The agent loop now honors the in-band error path: an adapter that ends
its stream with finish {kind:error|aborted} (the only option for
adapters that can't throw mid-stream, like pi-ai) is translated into a
step error, so the turn ends error/aborted with a logged error event
instead of a normal completed assistant message. This makes the
StreamChunk error contract real for both adapters; docs/architecture.md
and the StreamChunk doc are updated accordingly.

New yarn test:e2e (vitest.e2e.config.ts, *.e2e.ts) runs key-gated
real-API matrices for both adapters across V4 Flash/Pro and all
thinking/effort levels; it self-skips without DEEPSEEK_API_KEY. Unit
suites run against local node:http mock SSE servers at 100% per-file
coverage.
2026-06-13 18:30:03 +08:00
Tianyi Cui
8b5a3ef730 Add bash execution: dsh-bash seam, dsh-bash-local impl, dsh-tool-bash tools
Three packages following the new capability-seam pattern (interface /
implementation / consumer, now documented in docs/architecture.md):

- dsh-bash: abstract BashExecutor service (ctx.bash) + vocabulary types.
- dsh-bash-local: local subprocesses — bash -c per call in a detached
  process group, SIGTERM→SIGKILL group kills, tail-keep truncation with
  full-stream spill files, model-friendly env, background task registry.
- dsh-tool-bash: the bash / bash_output / bash_kill tool schemas with
  runtime arg validation and background completion notices via
  agent.inject(). Non-zero exits are reported, not errored.

Design surveyed against the bash tools of Claude Code, OpenCode, Codex,
and pi (notes in the package READMEs). Permissions/sandbox stay TODO on
the tools/execute waterfall seam; stateful-shell alternatives recorded
in run.ts.
2026-06-13 18:28:10 +08:00
Tianyi Cui
630bbddf9a Replace dumble with tsdown for JS bundling
dumble (0.2.x, ~530 dl/wk, single-maintainer) was a bus-factor risk as
the load-bearing bundler. tsdown (rolldown-based, ~2.5M dl/wk, actively
maintained) replaces it while output stays list-identical, verified by
snapshot diff: 17 JS bundles, externals preserved, schemastery dual
.mjs/.cjs and logger-console node+browser entries intact.

Root tsdown.config.ts uses workspace globs ['vendor/*', 'packages/*']
(explicit, so examples/* stays excluded); two per-package overrides in
vendor/ cover the special shapes and are logged in vendor/README.md as
ours (not upstream sync surface). scripts/build.ts (dumble
orchestration) is deleted; yarn build = tsc -b && tsdown. tsc -b keeps
owning declarations (dts: false, clean: false).

Rationale recorded in ADR 0008 (also covers the direct-esbuild and
pkgroll alternatives).

Gates: lint, typecheck, 134 tests, hygiene (knip/publint/constraints),
demo smoke all green.
2026-06-11 22:34:43 +08:00
Tianyi Cui
4dafad4db6 Add RFCs for the remaining quality-proposal ideas
Eight proposals grouped by category, each with problem statement,
concrete plan, and risks: property-based testing over the
protocol-shaped core (chunk streams, event logs, schema DSL);
mutation testing as the counterweight to the 100%-coverage gate;
deterministic tests + a universal replay-invariant fixture + nightly
race stress; architectural conformance (dependency-cruiser rules and
the LlmAdapter conformance kit); runtime arg validation at the model
boundary with a structured error taxonomy and dev-mode invariants;
doc-sync enforcement (typechecked doc snippets, API reports);
supply-chain checks and nightly vendor-drift verification against the
manifest; and deep-readonly public surfaces (logged-vs-in-flight
mutability boundary). AGENTS.md points at docs/adr and docs/rfc.
2026-06-11 15:27:07 +08:00
Tianyi Cui
9b8fccc6f9 Backfill architecture decision records
Seven ADRs capturing the why behind decisions already made: vendoring
Cordis as source with a guarded manifest; the microkernel event
taxonomy with one swappable concrete loop; event-sourced sessions
with derived history and the append-before-emit ordering contract;
the provider-neutral content-block vocabulary (and why not
OpenAI/Anthropic shapes); the custom tool-schema DSL over schemastery;
tool schemas living in the prompt assembly; and mechanical quality
gates over prose guidelines (the agents-write-the-code rationale).
2026-06-11 15:24:14 +08:00
Tianyi Cui
2b447625fa Sync docs with the defineTool DSL and actual demo code
The architecture cookbook's tool-plugin example now uses defineTool
with typed args (the raw-JSON-Schema + `args: any` example contradicted
the type-safety policy it sits next to); a note explains raw schemas
remain the MCP interop path. The echo-agent README's mock-llm row now
matches the code (registerAdapter(['mock-echo'])) and the echo-tool
row mentions the typed registration.
2026-06-11 13:48:22 +08:00
Tianyi Cui
217b8ec0e2 Fix architecture-review findings in the loop and service packages
High (loop pipeline): agent/step-result now runs before the
assistant/message append so the session log records what tool dispatch
actually uses; abort is honored between tool calls, not just
mid-stream; steering drains at step start, pending steering overrides
a negative turn-continuation decision (/goal pattern), and leftover
steering is re-enqueued as queued messages so it is never stranded;
exceptions from turn-continuation listeners and session/flush are
contained to the turn (error event + agent/error) instead of killing
the driver loop.

Medium: disposal emits agent/status('disposed') and mid-turn disposal
records reason 'disposed'; duplicate LLM adapter registration throws
(all-or-nothing); SessionEvent is a real discriminated union (casts
removed); model-less agents fail with a clear actionable error unless
agent/request supplies a model.

Low: agent/queued and agent/steering carry the resolved MessageSource;
streamBlocks() yields strictly in stream order and flushes delta-only
blocks (matches generate()); BlockAssembler freezes blocks on
block-end and ignores stragglers from malformed streams; turn
numbering is a counter seeded from the log (fork-safe); LoopAgent's
stop disposer is infallible (a throwing status listener cannot skip
registry cleanup); AgentLoop.create uses a generator effect so stop
and unregister are independent disposables; SessionStore wires
onAppend inside its effect.

21 regression tests added (review-fixes.spec.ts), organized by
finding. Docs updated: loop pseudocode (status emissions, ordering,
error containment, steering guarantees) and waterfall composition
caveat in docs/architecture.md; AGENTS.md notes that excessive tests
are welcome.
2026-06-11 12:19:16 +08:00
Tianyi Cui
cacfae3cae Document the architecture and rewrite AGENTS.md
docs/architecture.md: layering, service map, event taxonomy, the
session/turn/step lifecycle, Cordis waterfall semantics, an extension
cookbook, the plugin sanity checklist mapping every MVP feature to its
extension mechanism, and the deferred-work TODO list (sub-agents,
persistence backends, compaction, DeepSeek V4 adapter, parallel tool
execution, streaming-protocol review).

AGENTS.md: repo layout, commands, conventions (dsh-* naming, ESM,
effect-based registrations, declaration merging, waterfall semantics),
and the vendoring policy pointer.
2026-06-11 10:55:05 +08:00