diff --git a/README.md b/README.md
index 43f8849..e243007 100644
--- a/README.md
+++ b/README.md
@@ -20,3 +20,17 @@ requirements documents in `wiki/`.
 
 The repo is registered with the Custodian State Hub as `markitect-tool` under
 the `markitect` domain. See `docs/state-hub-integration.md`.
+
+## Development
+
+Run the tests:
+
+```bash
+python3 -m pytest
+```
+
+Try the parser CLI from a checkout:
+
+```bash
+PYTHONPATH=src python3 -m markitect_tool parse README.md --format tree
+```
diff --git a/docs/packaging-decision.md b/docs/packaging-decision.md
new file mode 100644
index 0000000..8bce226
--- /dev/null
+++ b/docs/packaging-decision.md
@@ -0,0 +1,36 @@
+# Packaging Decision
+
+Date: 2026-05-03
+
+## Decision
+
+`markitect-tool` starts as a Python 3.12+ package with:
+
+- Distribution name: `markitect-tool`
+- Import package: `markitect_tool`
+- CLI entry point: `mkt`
+- Build backend: `setuptools`
+- Test runner: `pytest`
+- Source layout: `src/markitect_tool`
+
+## Initial Dependencies
+
+Core dependencies:
+
+- `markdown-it-py`
+- `PyYAML`
+- `click>=8.0`
+
+Optional extras:
+
+- `query`: `jsonpath-ng`
+- `tables`: `tabulate`
+- `llm`: `llm-connect`
+- `dev`: `pytest`
+
+## Rationale
+
+This follows the WP-0002 dependency classification and keeps the first
+implementation focused on deterministic markdown parsing and CLI access. The
+package name avoids legacy `markitect.*` imports while the `mkt` entry point
+matches the PRD.
diff --git a/docs/state-hub-integration.md b/docs/state-hub-integration.md
index 3009493..c6bc8ce 100644
--- a/docs/state-hub-integration.md
+++ b/docs/state-hub-integration.md
@@ -32,8 +32,10 @@ workplans/
 
 ## Follow-Up
 
-Once implementation dependencies exist, add an SBOM source and update State Hub
-with the SBOM ingestion result. This seed repo currently has no package manifest.
+SBOM source: `sbom-tools.yaml`.
+
+Initial SBOM ingest succeeded on 2026-05-03 with seven declared entries for the
+core and optional dependencies.
 
 ## Registered Extension Points
 
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..52ef696
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,40 @@
+[build-system]
+requires = ["setuptools>=69"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "markitect-tool"
+version = "0.1.0"
+description = "Markdown-native toolkit and CLI for structured knowledge artifacts"
+readme = "README.md"
+requires-python = ">=3.12"
+license = { text = "MIT" }
+dependencies = [
+    "click>=8.0",
+    "markdown-it-py",
+    "PyYAML",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest>=8",
+]
+query = [
+    "jsonpath-ng>=1.5",
+]
+tables = [
+    "tabulate>=0.9",
+]
+llm = [
+    "llm-connect @ file:///home/worsch/llm-connect",
+]
+
+[project.scripts]
+mkt = "markitect_tool.cli:main"
+
+[tool.setuptools.packages.find]
+where = ["src"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+pythonpath = ["src"]
diff --git a/sbom-tools.yaml b/sbom-tools.yaml
new file mode 100644
index 0000000..a39110e
--- /dev/null
+++ b/sbom-tools.yaml
@@ -0,0 +1,29 @@
+tools:
+  - name: click
+    ecosystem: python
+    is_direct: true
+    is_dev: false
+  - name: markdown-it-py
+    ecosystem: python
+    is_direct: true
+    is_dev: false
+  - name: PyYAML
+    ecosystem: python
+    is_direct: true
+    is_dev: false
+  - name: pytest
+    ecosystem: python
+    is_direct: true
+    is_dev: true
+  - name: jsonpath-ng
+    ecosystem: python
+    is_direct: true
+    is_dev: false
+  - name: tabulate
+    ecosystem: python
+    is_direct: true
+    is_dev: false
+  - name: llm-connect
+    ecosystem: python
+    is_direct: true
+    is_dev: false
diff --git a/src/markitect_tool/__init__.py b/src/markitect_tool/__init__.py
new file mode 100644
index 0000000..3b18cf9
--- /dev/null
+++ b/src/markitect_tool/__init__.py
@@ -0,0 +1,21 @@
+"""Structured markdown primitives for markitect-tool."""
+
+from markitect_tool.core import (
+    ContentBlock,
+    Document,
+    Heading,
+    MarkdownParseError,
+    Section,
+    parse_markdown,
+    parse_markdown_file,
+)
+
+__all__ = [
+    "ContentBlock",
+    "Document",
+    "Heading",
+    "MarkdownParseError",
+    "Section",
+    "parse_markdown",
+    "parse_markdown_file",
+]
diff --git a/src/markitect_tool/__main__.py b/src/markitect_tool/__main__.py
new file mode 100644
index 0000000..d507947
--- /dev/null
+++ b/src/markitect_tool/__main__.py
@@ -0,0 +1,6 @@
+"""Run the `mkt` CLI with `python -m markitect_tool`."""
+
+from markitect_tool.cli import main
+
+
+main()
diff --git a/src/markitect_tool/cli/__init__.py b/src/markitect_tool/cli/__init__.py
new file mode 100644
index 0000000..80262a9
--- /dev/null
+++ b/src/markitect_tool/cli/__init__.py
@@ -0,0 +1,5 @@
+"""Command-line interface for markitect-tool."""
+
+from markitect_tool.cli.main import main
+
+__all__ = ["main"]
diff --git a/src/markitect_tool/cli/main.py b/src/markitect_tool/cli/main.py
new file mode 100644
index 0000000..3b52d7a
--- /dev/null
+++ b/src/markitect_tool/cli/main.py
@@ -0,0 +1,44 @@
+"""`mkt` command entry point."""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+import click
+import yaml
+
+from markitect_tool.core import parse_markdown_file
+
+
+@click.group()
+@click.version_option()
+def main() -> None:
+    """Markdown-native toolkit for structured knowledge artifacts."""
+
+
+@main.command()
+@click.argument("file", type=click.Path(exists=True, dir_okay=False, path_type=Path))
+@click.option(
+    "--format",
+    "output_format",
+    type=click.Choice(["json", "yaml", "tree"], case_sensitive=False),
+    default="json",
+    show_default=True,
+)
+def parse(file: Path, output_format: str) -> None:
+    """Parse a Markdown file into a structured representation."""
+
+    document = parse_markdown_file(file)
+    data = document.to_dict()
+    if output_format == "yaml":
+        click.echo(yaml.safe_dump(data, sort_keys=False))
+    elif output_format == "tree":
+        for heading in document.headings:
+            click.echo(f"{'#' * heading.level} {heading.text}")
+    else:
+        click.echo(json.dumps(data, indent=2, ensure_ascii=False))
+
+
+if __name__ == "__main__":
+    main()
diff --git a/src/markitect_tool/core/__init__.py b/src/markitect_tool/core/__init__.py
new file mode 100644
index 0000000..3ce841b
--- /dev/null
+++ b/src/markitect_tool/core/__init__.py
@@ -0,0 +1,14 @@
+"""Core markdown parsing and document model."""
+
+from markitect_tool.core.document import ContentBlock, Document, Heading, Section
+from markitect_tool.core.parser import MarkdownParseError, parse_markdown, parse_markdown_file
+
+__all__ = [
+    "ContentBlock",
+    "Document",
+    "Heading",
+    "MarkdownParseError",
+    "Section",
+    "parse_markdown",
+    "parse_markdown_file",
+]
diff --git a/src/markitect_tool/core/document.py b/src/markitect_tool/core/document.py
new file mode 100644
index 0000000..e749e56
--- /dev/null
+++ b/src/markitect_tool/core/document.py
@@ -0,0 +1,72 @@
+"""Structured document model for parsed Markdown."""
+
+from __future__ import annotations
+
+from dataclasses import asdict, dataclass, field
+from typing import Any
+
+
+@dataclass(frozen=True)
+class Heading:
+    """A Markdown heading with source location."""
+
+    level: int
+    text: str
+    line: int
+
+    def to_dict(self) -> dict[str, Any]:
+        return asdict(self)
+
+
+@dataclass(frozen=True)
+class ContentBlock:
+    """A top-level Markdown content block."""
+
+    type: str
+    text: str
+    line_start: int | None = None
+    line_end: int | None = None
+    heading_level: int | None = None
+
+    def to_dict(self) -> dict[str, Any]:
+        data = asdict(self)
+        return {key: value for key, value in data.items() if value is not None}
+
+
+@dataclass(frozen=True)
+class Section:
+    """A heading-led section."""
+
+    heading: Heading
+    blocks: list[ContentBlock] = field(default_factory=list)
+
+    def to_dict(self) -> dict[str, Any]:
+        return {
+            "heading": self.heading.to_dict(),
+            "blocks": [block.to_dict() for block in self.blocks],
+        }
+
+
+@dataclass(frozen=True)
+class Document:
+    """Structured representation of a Markdown document."""
+
+    source_path: str | None
+    frontmatter: dict[str, Any]
+    body: str
+    blocks: list[ContentBlock]
+    headings: list[Heading]
+    sections: list[Section]
+    tokens: list[dict[str, Any]]
+
+    def to_dict(self) -> dict[str, Any]:
+        data = {
+            "source_path": self.source_path,
+            "frontmatter": self.frontmatter,
+            "body": self.body,
+            "blocks": [block.to_dict() for block in self.blocks],
+            "headings": [heading.to_dict() for heading in self.headings],
+            "sections": [section.to_dict() for section in self.sections],
+            "tokens": self.tokens,
+        }
+        return {key: value for key, value in data.items() if value is not None}
diff --git a/src/markitect_tool/core/parser.py b/src/markitect_tool/core/parser.py
new file mode 100644
index 0000000..3ae44a3
--- /dev/null
+++ b/src/markitect_tool/core/parser.py
@@ -0,0 +1,182 @@
+"""Markdown parsing into a stable structured representation."""
+
+from __future__ import annotations
+
+from pathlib import Path
+from typing import Any
+
+import yaml
+from markdown_it import MarkdownIt
+from markdown_it.token import Token
+
+from markitect_tool.core.document import ContentBlock, Document, Heading, Section
+
+
+class MarkdownParseError(ValueError):
+    """Raised when Markdown metadata cannot be parsed safely."""
+
+
+def parse_markdown_file(path: str | Path) -> Document:
+    """Parse a Markdown file into a structured document."""
+
+    file_path = Path(path)
+    text = file_path.read_text(encoding="utf-8")
+    return parse_markdown(text, source_path=str(file_path))
+
+
+def parse_markdown(markdown: str, source_path: str | None = None) -> Document:
+    """Parse Markdown text into frontmatter, blocks, headings, sections, and tokens."""
+
+    frontmatter, body, body_line_offset = _split_frontmatter(markdown)
+    tokens = _parse_tokens(body)
+    blocks, headings = _blocks_and_headings(tokens, body_line_offset)
+    sections = _sections_from_blocks(blocks, headings)
+    return Document(
+        source_path=source_path,
+        frontmatter=frontmatter,
+        body=body,
+        blocks=blocks,
+        headings=headings,
+        sections=sections,
+        tokens=tokens,
+    )
+
+
+def _split_frontmatter(markdown: str) -> tuple[dict[str, Any], str, int]:
+    if not markdown.startswith("---\n"):
+        return {}, markdown, 0
+
+    end = markdown.find("\n---", 4)
+    if end == -1:
+        return {}, markdown, 0
+
+    closing_end = markdown.find("\n", end + 4)
+    if closing_end == -1:
+        closing_end = len(markdown)
+    else:
+        closing_end += 1
+
+    raw_frontmatter = markdown[4:end]
+    body = markdown[closing_end:]
+    try:
+        data = yaml.safe_load(raw_frontmatter) if raw_frontmatter.strip() else {}
+    except yaml.YAMLError as exc:
+        raise MarkdownParseError(f"Invalid YAML frontmatter: {exc}") from exc
+    if data is None:
+        data = {}
+    if not isinstance(data, dict):
+        raise MarkdownParseError("Frontmatter must be a mapping")
+    body_line_offset = markdown[:closing_end].count("\n")
+    return data, body, body_line_offset
+
+
+def _parse_tokens(markdown: str) -> list[dict[str, Any]]:
+    parser = MarkdownIt("commonmark", {"tables": True}).enable("table")
+    return [_token_to_dict(token) for token in parser.parse(markdown)]
+
+
+def _token_to_dict(token: Token) -> dict[str, Any]:
+    data = {
+        "type": token.type,
+        "tag": token.tag,
+        "attrs": token.attrs,
+        "map": token.map,
+        "nesting": token.nesting,
+        "level": token.level,
+        "children": [_token_to_dict(child) for child in token.children]
+        if token.children
+        else None,
+        "content": token.content,
+        "markup": token.markup,
+        "info": token.info,
+        "meta": token.meta,
+        "block": token.block,
+        "hidden": token.hidden,
+    }
+    return {key: value for key, value in data.items() if value is not None}
+
+
+def _blocks_and_headings(
+    tokens: list[dict[str, Any]], line_offset: int
+) -> tuple[list[ContentBlock], list[Heading]]:
+    blocks: list[ContentBlock] = []
+    headings: list[Heading] = []
+
+    for index, token in enumerate(tokens):
+        token_type = token["type"]
+        if token_type == "heading_open":
+            inline = _next_inline(tokens, index)
+            line_start, line_end = _line_range(token, line_offset)
+            level = int(token.get("tag", "h1").lstrip("h") or "1")
+            text = inline.get("content", "") if inline else ""
+            heading = Heading(level=level, text=text, line=line_start or 1)
+            headings.append(heading)
+            blocks.append(
+                ContentBlock(
+                    type="heading",
+                    text=text,
+                    line_start=line_start,
+                    line_end=line_end,
+                    heading_level=level,
+                )
+            )
+        elif token_type in {"paragraph_open", "bullet_list_open", "ordered_list_open", "blockquote_open", "fence", "code_block", "table_open"}:
+            line_start, line_end = _line_range(token, line_offset)
+            text = token.get("content", "")
+            if not text and token_type.endswith("_open"):
+                inline = _next_inline(tokens, index)
+                text = inline.get("content", "") if inline else ""
+            blocks.append(
+                ContentBlock(
+                    type=_block_type(token_type),
+                    text=text,
+                    line_start=line_start,
+                    line_end=line_end,
+                )
+            )
+
+    return blocks, headings
+
+
+def _next_inline(tokens: list[dict[str, Any]], index: int) -> dict[str, Any] | None:
+    if index + 1 < len(tokens) and tokens[index + 1]["type"] == "inline":
+        return tokens[index + 1]
+    return None
+
+
+def _line_range(token: dict[str, Any], line_offset: int) -> tuple[int | None, int | None]:
+    line_map = token.get("map")
+    if not line_map:
+        return None, None
+    return line_map[0] + line_offset + 1, line_map[1] + line_offset
+
+
+def _block_type(token_type: str) -> str:
+    return {
+        "paragraph_open": "paragraph",
+        "bullet_list_open": "bullet_list",
+        "ordered_list_open": "ordered_list",
+        "blockquote_open": "blockquote",
+        "fence": "code",
+        "code_block": "code",
+        "table_open": "table",
+    }.get(token_type, token_type)
+
+
+def _sections_from_blocks(
+    blocks: list[ContentBlock], headings: list[Heading]
+) -> list[Section]:
+    sections: list[Section] = []
+    current: Section | None = None
+    heading_index = 0
+
+    for block in blocks:
+        if block.type == "heading":
+            heading = headings[heading_index]
+            heading_index += 1
+            current = Section(heading=heading, blocks=[])
+            sections.append(current)
+        elif current is not None:
+            current.blocks.append(block)
+
+    return sections
diff --git a/tests/test_parse_contract.py b/tests/test_parse_contract.py
new file mode 100644
index 0000000..5a20ae8
--- /dev/null
+++ b/tests/test_parse_contract.py
@@ -0,0 +1,89 @@
+from pathlib import Path
+
+import pytest
+from click.testing import CliRunner
+
+from markitect_tool import MarkdownParseError, parse_markdown, parse_markdown_file
+from markitect_tool.cli import main
+
+
+def test_parse_markdown_preserves_headings_and_paragraphs():
+    document = parse_markdown("# Heading\n\nThis is a paragraph.")
+
+    assert document.frontmatter == {}
+    assert document.headings[0].level == 1
+    assert document.headings[0].text == "Heading"
+    assert [block.type for block in document.blocks] == ["heading", "paragraph"]
+    assert document.sections[0].heading.text == "Heading"
+    assert document.sections[0].blocks[0].text == "This is a paragraph."
+    assert document.tokens[0]["type"] == "heading_open"
+
+
+def test_parse_markdown_extracts_yaml_frontmatter():
+    markdown = """---
+title: YAML Frontmatter Test Document
+tags:
+  - yaml
+  - frontmatter
+published: true
+nested:
+  priority: high
+---
+
+# YAML Frontmatter Test Document
+
+Body text.
+"""
+
+    document = parse_markdown(markdown)
+
+    assert document.frontmatter["title"] == "YAML Frontmatter Test Document"
+    assert document.frontmatter["tags"] == ["yaml", "frontmatter"]
+    assert document.frontmatter["published"] is True
+    assert document.frontmatter["nested"]["priority"] == "high"
+    assert document.headings[0].line == 11
+    assert document.body.lstrip().startswith("# YAML Frontmatter Test Document")
+
+
+def test_parse_markdown_without_frontmatter_is_graceful():
+    document = parse_markdown("# Document Without Frontmatter\n\nText.")
+
+    assert document.frontmatter == {}
+    assert document.headings[0].text == "Document Without Frontmatter"
+
+
+def test_parse_markdown_rejects_non_mapping_frontmatter():
+    with pytest.raises(MarkdownParseError, match="Frontmatter must be a mapping"):
+        parse_markdown("---\n- nope\n---\n\n# Bad")
+
+
+def test_parse_markdown_file_records_source_path(tmp_path: Path):
+    source = tmp_path / "doc.md"
+    source.write_text("# Test Document\n\nBody", encoding="utf-8")
+
+    document = parse_markdown_file(source)
+
+    assert document.source_path == str(source)
+    assert document.headings[0].text == "Test Document"
+
+
+def test_mkt_parse_outputs_json(tmp_path: Path):
+    source = tmp_path / "doc.md"
+    source.write_text("# Test Document\n\nBody", encoding="utf-8")
+
+    result = CliRunner().invoke(main, ["parse", str(source)])
+
+    assert result.exit_code == 0
+    assert '"headings"' in result.output
+    assert "Test Document" in result.output
+
+
+def test_mkt_parse_outputs_tree(tmp_path: Path):
+    source = tmp_path / "doc.md"
+    source.write_text("# One\n\n## Two\n", encoding="utf-8")
+
+    result = CliRunner().invoke(main, ["parse", str(source), "--format", "tree"])
+
+    assert result.exit_code == 0
+    assert "# One" in result.output
+    assert "## Two" in result.output
diff --git a/workplans/MKTT-WP-0001-repo-foundation.md b/workplans/MKTT-WP-0001-repo-foundation.md
index d64ac07..ea26aa8 100644
--- a/workplans/MKTT-WP-0001-repo-foundation.md
+++ b/workplans/MKTT-WP-0001-repo-foundation.md
@@ -58,7 +58,7 @@ migration assessment, and implementation.
 
 ```task
 id: MKTT-WP-0001-T004
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "c15f8492-93d0-43aa-ba12-0d4aaff97c03"
 ```
@@ -67,11 +67,13 @@ Choose package/module names, Python version target, dependency manager, and
 test runner. Keep the decision lightweight and aligned with the future `mkt`
 CLI entry point.
 
+Output: `docs/packaging-decision.md`.
+
 ## P1.5 - Add SBOM source once manifests exist
 
 ```task
 id: MKTT-WP-0001-T005
-status: blocked
+status: done
 priority: medium
 state_hub_task_id: "e77a5e46-aaa2-4717-922f-a871fa2fd1cc"
 ```
@@ -79,4 +81,4 @@ state_hub_task_id: "e77a5e46-aaa2-4717-922f-a871fa2fd1cc"
 After packaging files are introduced, generate or identify the SBOM source and
 update State Hub registration metadata.
 
-Blocked because the repository has no implementation package manifest yet.
+Output: `sbom-tools.yaml`; initial State Hub ingest succeeded on 2026-05-03.
diff --git a/workplans/MKTT-WP-0003-core-toolkit-implementation.md b/workplans/MKTT-WP-0003-core-toolkit-implementation.md
index c771be6..da3a0f6 100644
--- a/workplans/MKTT-WP-0003-core-toolkit-implementation.md
+++ b/workplans/MKTT-WP-0003-core-toolkit-implementation.md
@@ -22,7 +22,7 @@ contract and the `mkt` CLI.
 
 ```task
 id: MKTT-WP-0003-T001
-status: todo
+status: done
 priority: high
 state_hub_task_id: "9d9501fe-6809-4b4f-bda6-ec5e5952ddc7"
 ```
@@ -30,11 +30,13 @@ state_hub_task_id: "9d9501fe-6809-4b4f-bda6-ec5e5952ddc7"
 Create project metadata, package layout, test structure, and a minimal CLI
 entry point that can be installed or run locally.
 
+Output: `pyproject.toml`, `src/markitect_tool/`, `tests/`.
+
 ## P3.2 - Implement structured markdown parse contract
 
 ```task
 id: MKTT-WP-0003-T002
-status: todo
+status: done
 priority: high
 state_hub_task_id: "7dead033-e249-46b0-9eb3-908ae231a987"
 ```
@@ -43,6 +45,9 @@ Implement FR-001 and FR-002: parse markdown files, preserve headings,
 frontmatter, sections, and content blocks, and expose structured output via
 API and CLI.
 
+Initial implementation complete for Markdown files, YAML frontmatter, headings,
+sections, content blocks, parser tokens, API access, and `mkt parse`.
+
 ## P3.3 - Implement schema load and validation
 
 ```task
@@ -108,10 +113,12 @@ Implement FR-070 and FR-071 after the parse/schema contracts are stable.
 
 ```task
 id: MKTT-WP-0003-T008
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "94067c7e-e68b-45be-a1d6-90547eb15422"
 ```
 
 Resolve `TD-MKTT-001` by adding the implementation scaffold: package metadata,
 module layout, test runner, and `mkt` CLI entry point.
+
+Resolved by the initial package scaffold.