diff --git a/.gitea/workflows/ci.yml b/.gitea/workflows/ci.yml
new file mode 100644
index 0000000..edd6079
--- /dev/null
+++ b/.gitea/workflows/ci.yml
@@ -0,0 +1,70 @@
+# Continuous integration for the NATO alphabet project.
+#
+# Purpose:  run the pytest suite on Python 3.13 so a change is known to work
+#           before it is merged (BC-001 objective O3, success criterion 2).
+# Triggers: a push to main or to a milestone branch, and every pull request
+#           that touches source, tests, project configuration or this file.
+# Inputs:   none.
+# Secrets:  none. The job reads the repository only.
+# Changes:  nothing outside the repository.
+# Decision: MIL-001 task "Add the CI workflow".
+# Host:     Gitea Actions (act_runner); the same file runs on GitHub Actions.
+#           The runner must offer the label ubuntu-latest.
+
+name: CI
+
+on:
+  push:
+    branches: [main, "mil-*"]
+    paths:
+      - "src/**"
+      - "tests/**"
+      - "pyproject.toml"
+      - ".gitea/workflows/ci.yml"
+  pull_request:
+    paths:
+      - "src/**"
+      - "tests/**"
+      - "pyproject.toml"
+      - ".gitea/workflows/ci.yml"
+
+# A newer run of the same branch makes the older one pointless.
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  PYTHON_VERSION: "3.13"
+
+jobs:
+  test:
+    name: Test on Python 3.13
+    permissions:
+      contents: read
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - name: Check out the repository
+        uses: actions/checkout@v4.2.2
+
+      - name: Set up Python
+        uses: actions/setup-python@v5.6.0
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+
+      - name: Create the virtual environment and upgrade pip
+        run: |
+          python -m venv .venv
+          .venv/bin/python -m pip install --upgrade pip
+
+      - name: Install the project with its development tools
+        run: .venv/bin/python -m pip install -e ".[dev]"
+
+      - name: Check the code style
+        run: .venv/bin/python -m ruff check .
+
+      - name: Check the types
+        run: .venv/bin/python -m mypy
+
+      - name: Run the tests
+        run: .venv/bin/python -m pytest
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ec4969e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,33 @@
+# Byte-compiled and cache files
+__pycache__/
+*.py[cod]
+.pytest_cache/
+.mypy_cache/
+.ruff_cache/
+.import_linter_cache/
+
+# Virtual environments
+.venv/
+venv/
+env/
+
+# Packaging, build and Doxygen output
+build/
+dist/
+*.egg-info/
+.eggs/
+
+# Coverage
+.coverage
+htmlcov/
+
+# Secrets and local configuration (personal tokens, never committed)
+.env
+.env.*
+!.env.example
+
+# Editors and operating system
+.idea/
+.vscode/
+.DS_Store
+Thumbs.db
diff --git a/.yamllint.yml b/.yamllint.yml
new file mode 100644
index 0000000..314e874
--- /dev/null
+++ b/.yamllint.yml
@@ -0,0 +1,8 @@
+# yamllint configuration for the repository's YAML files (tool: yamllint).
+extends: default
+rules:
+  line-length:
+    max: 100
+  truthy:
+    check-keys: false
+  document-start: disable
diff --git a/Doxyfile b/Doxyfile
new file mode 100644
index 0000000..4248036
--- /dev/null
+++ b/Doxyfile
@@ -0,0 +1,374 @@
+# Doxyfile 1.15.0
+
+#---------------------------------------------------------------------------
+# Project related configuration options
+#---------------------------------------------------------------------------
+DOXYFILE_ENCODING      = UTF-8
+PROJECT_NAME           = "NATO alphabet"
+PROJECT_NUMBER         =
+PROJECT_BRIEF          = "Spell a word with the NATO phonetic alphabet (100 Days of Code, day 26)"
+PROJECT_LOGO           =
+PROJECT_ICON           =
+OUTPUT_DIRECTORY       = build
+CREATE_SUBDIRS         = NO
+CREATE_SUBDIRS_LEVEL   = 8
+ALLOW_UNICODE_NAMES    = NO
+OUTPUT_LANGUAGE        = English
+BRIEF_MEMBER_DESC      = YES
+REPEAT_BRIEF           = YES
+ABBREVIATE_BRIEF       = "The $name class" \
+                         "The $name widget" \
+                         "The $name file" \
+                         is \
+                         provides \
+                         specifies \
+                         contains \
+                         represents \
+                         a \
+                         an \
+                         the
+ALWAYS_DETAILED_SEC    = NO
+INLINE_INHERITED_MEMB  = NO
+FULL_PATH_NAMES        = YES
+STRIP_FROM_PATH        =
+STRIP_FROM_INC_PATH    =
+SHORT_NAMES            = NO
+JAVADOC_AUTOBRIEF      = NO
+JAVADOC_BANNER         = NO
+QT_AUTOBRIEF           = NO
+MULTILINE_CPP_IS_BRIEF = NO
+PYTHON_DOCSTRING       = YES
+INHERIT_DOCS           = YES
+SEPARATE_MEMBER_PAGES  = NO
+TAB_SIZE               = 4
+ALIASES                =
+OPTIMIZE_OUTPUT_FOR_C  = NO
+OPTIMIZE_OUTPUT_JAVA   = YES
+OPTIMIZE_FOR_FORTRAN   = NO
+OPTIMIZE_OUTPUT_VHDL   = NO
+OPTIMIZE_OUTPUT_SLICE  = NO
+EXTENSION_MAPPING      =
+MARKDOWN_SUPPORT       = YES
+MARKDOWN_STRICT        = YES
+TOC_INCLUDE_HEADINGS   = 6
+MARKDOWN_ID_STYLE      = DOXYGEN
+AUTOLINK_SUPPORT       = YES
+AUTOLINK_IGNORE_WORDS  =
+BUILTIN_STL_SUPPORT    = NO
+CPP_CLI_SUPPORT        = NO
+SIP_SUPPORT            = NO
+IDL_PROPERTY_SUPPORT   = YES
+DISTRIBUTE_GROUP_DOC   = NO
+GROUP_NESTED_COMPOUNDS = NO
+SUBGROUPING            = YES
+INLINE_GROUPED_CLASSES = NO
+INLINE_SIMPLE_STRUCTS  = NO
+TYPEDEF_HIDES_STRUCT   = NO
+LOOKUP_CACHE_SIZE      = 0
+NUM_PROC_THREADS       = 1
+TIMESTAMP              = NO
+#---------------------------------------------------------------------------
+# Build related configuration options
+#---------------------------------------------------------------------------
+EXTRACT_ALL            = NO
+EXTRACT_PRIVATE        = NO
+EXTRACT_PRIV_VIRTUAL   = NO
+EXTRACT_PACKAGE        = NO
+EXTRACT_STATIC         = NO
+EXTRACT_LOCAL_CLASSES  = YES
+EXTRACT_LOCAL_METHODS  = NO
+EXTRACT_ANON_NSPACES   = NO
+RESOLVE_UNNAMED_PARAMS = YES
+HIDE_UNDOC_MEMBERS     = NO
+HIDE_UNDOC_CLASSES     = NO
+HIDE_UNDOC_NAMESPACES  = YES
+HIDE_FRIEND_COMPOUNDS  = NO
+HIDE_IN_BODY_DOCS      = NO
+INTERNAL_DOCS          = NO
+CASE_SENSE_NAMES       = SYSTEM
+HIDE_SCOPE_NAMES       = NO
+HIDE_COMPOUND_REFERENCE= NO
+SHOW_HEADERFILE        = YES
+SHOW_INCLUDE_FILES     = YES
+SHOW_GROUPED_MEMB_INC  = NO
+FORCE_LOCAL_INCLUDES   = NO
+INLINE_INFO            = YES
+SORT_MEMBER_DOCS       = YES
+SORT_BRIEF_DOCS        = NO
+SORT_MEMBERS_CTORS_1ST = NO
+SORT_GROUP_NAMES       = NO
+SORT_BY_SCOPE_NAME     = NO
+STRICT_PROTO_MATCHING  = NO
+GENERATE_TODOLIST      = YES
+GENERATE_TESTLIST      = YES
+GENERATE_BUGLIST       = YES
+GENERATE_DEPRECATEDLIST= YES
+ENABLED_SECTIONS       =
+MAX_INITIALIZER_LINES  = 30
+SHOW_USED_FILES        = YES
+SHOW_FILES             = YES
+SHOW_NAMESPACES        = YES
+FILE_VERSION_FILTER    =
+LAYOUT_FILE            =
+CITE_BIB_FILES         =
+EXTERNAL_TOOL_PATH     =
+#---------------------------------------------------------------------------
+# Configuration options related to warning and progress messages
+#---------------------------------------------------------------------------
+QUIET                  = YES
+WARNINGS               = YES
+WARN_IF_UNDOCUMENTED   = YES
+WARN_IF_DOC_ERROR      = YES
+WARN_IF_INCOMPLETE_DOC = YES
+WARN_NO_PARAMDOC       = NO
+WARN_IF_UNDOC_ENUM_VAL = NO
+WARN_LAYOUT_FILE       = YES
+WARN_AS_ERROR          = FAIL_ON_WARNINGS
+WARN_FORMAT            = "$file:$line: $text"
+WARN_LINE_FORMAT       = "at line $line of file $file"
+WARN_LOGFILE           =
+#---------------------------------------------------------------------------
+# Configuration options related to the input files
+#---------------------------------------------------------------------------
+INPUT                  = src README.md
+INPUT_ENCODING         = UTF-8
+INPUT_FILE_ENCODING    =
+FILE_PATTERNS          = *.py *.md
+RECURSIVE              = YES
+EXCLUDE                =
+EXCLUDE_SYMLINKS       = NO
+EXCLUDE_PATTERNS       =
+EXCLUDE_SYMBOLS        =
+EXAMPLE_PATH           =
+EXAMPLE_PATTERNS       = *
+EXAMPLE_RECURSIVE      = NO
+IMAGE_PATH             =
+INPUT_FILTER           =
+FILTER_PATTERNS        =
+FILTER_SOURCE_FILES    = NO
+FILTER_SOURCE_PATTERNS =
+USE_MDFILE_AS_MAINPAGE = README.md
+IMPLICIT_DIR_DOCS      = YES
+FORTRAN_COMMENT_AFTER  = 72
+#---------------------------------------------------------------------------
+# Configuration options related to source browsing
+#---------------------------------------------------------------------------
+SOURCE_BROWSER         = NO
+INLINE_SOURCES         = NO
+STRIP_CODE_COMMENTS    = YES
+REFERENCED_BY_RELATION = NO
+REFERENCES_RELATION    = NO
+REFERENCES_LINK_SOURCE = YES
+SOURCE_TOOLTIPS        = YES
+USE_HTAGS              = NO
+VERBATIM_HEADERS       = YES
+CLANG_ASSISTED_PARSING = NO
+CLANG_ADD_INC_PATHS    = YES
+CLANG_OPTIONS          =
+CLANG_DATABASE_PATH    =
+#---------------------------------------------------------------------------
+# Configuration options related to the alphabetical class index
+#---------------------------------------------------------------------------
+ALPHABETICAL_INDEX     = YES
+IGNORE_PREFIX          =
+#---------------------------------------------------------------------------
+# Configuration options related to the HTML output
+#---------------------------------------------------------------------------
+GENERATE_HTML          = YES
+HTML_OUTPUT            = html
+HTML_FILE_EXTENSION    = .html
+HTML_HEADER            =
+HTML_FOOTER            =
+HTML_STYLESHEET        =
+HTML_EXTRA_STYLESHEET  =
+HTML_EXTRA_FILES       =
+HTML_COLORSTYLE        = AUTO_LIGHT
+HTML_COLORSTYLE_HUE    = 220
+HTML_COLORSTYLE_SAT    = 100
+HTML_COLORSTYLE_GAMMA  = 80
+HTML_DYNAMIC_MENUS     = YES
+HTML_DYNAMIC_SECTIONS  = NO
+HTML_CODE_FOLDING      = YES
+HTML_COPY_CLIPBOARD    = YES
+HTML_PROJECT_COOKIE    =
+HTML_INDEX_NUM_ENTRIES = 100
+GENERATE_DOCSET        = NO
+DOCSET_FEEDNAME        = "Doxygen generated docs"
+DOCSET_FEEDURL         =
+DOCSET_BUNDLE_ID       = org.doxygen.Project
+DOCSET_PUBLISHER_ID    = org.doxygen.Publisher
+DOCSET_PUBLISHER_NAME  = Publisher
+GENERATE_HTMLHELP      = NO
+CHM_FILE               =
+HHC_LOCATION           =
+GENERATE_CHI           = NO
+CHM_INDEX_ENCODING     =
+BINARY_TOC             = NO
+TOC_EXPAND             = NO
+SITEMAP_URL            =
+GENERATE_QHP           = NO
+QCH_FILE               =
+QHP_NAMESPACE          = org.doxygen.Project
+QHP_VIRTUAL_FOLDER     = doc
+QHP_CUST_FILTER_NAME   =
+QHP_CUST_FILTER_ATTRS  =
+QHP_SECT_FILTER_ATTRS  =
+QHG_LOCATION           =
+GENERATE_ECLIPSEHELP   = NO
+ECLIPSE_DOC_ID         = org.doxygen.Project
+DISABLE_INDEX          = NO
+GENERATE_TREEVIEW      = YES
+PAGE_OUTLINE_PANEL     = YES
+FULL_SIDEBAR           = NO
+ENUM_VALUES_PER_LINE   = 4
+SHOW_ENUM_VALUES       = NO
+TREEVIEW_WIDTH         = 250
+EXT_LINKS_IN_WINDOW    = NO
+OBFUSCATE_EMAILS       = YES
+HTML_FORMULA_FORMAT    = png
+FORMULA_FONTSIZE       = 10
+FORMULA_MACROFILE      =
+USE_MATHJAX            = NO
+MATHJAX_VERSION        = MathJax_2
+MATHJAX_FORMAT         = HTML-CSS
+MATHJAX_RELPATH        =
+MATHJAX_EXTENSIONS     =
+MATHJAX_CODEFILE       =
+SEARCHENGINE           = YES
+SERVER_BASED_SEARCH    = NO
+EXTERNAL_SEARCH        = NO
+SEARCHENGINE_URL       =
+SEARCHDATA_FILE        = searchdata.xml
+EXTERNAL_SEARCH_ID     =
+EXTRA_SEARCH_MAPPINGS  =
+#---------------------------------------------------------------------------
+# Configuration options related to the LaTeX output
+#---------------------------------------------------------------------------
+GENERATE_LATEX         = NO
+LATEX_OUTPUT           = latex
+LATEX_CMD_NAME         =
+MAKEINDEX_CMD_NAME     = makeindex
+LATEX_MAKEINDEX_CMD    = makeindex
+COMPACT_LATEX          = NO
+PAPER_TYPE             = a4
+EXTRA_PACKAGES         =
+LATEX_HEADER           =
+LATEX_FOOTER           =
+LATEX_EXTRA_STYLESHEET =
+LATEX_EXTRA_FILES      =
+PDF_HYPERLINKS         = YES
+USE_PDFLATEX           = YES
+LATEX_BATCHMODE        = NO
+LATEX_HIDE_INDICES     = NO
+LATEX_BIB_STYLE        = plainnat
+LATEX_EMOJI_DIRECTORY  =
+#---------------------------------------------------------------------------
+# Configuration options related to the RTF output
+#---------------------------------------------------------------------------
+GENERATE_RTF           = NO
+RTF_OUTPUT             = rtf
+COMPACT_RTF            = NO
+RTF_HYPERLINKS         = NO
+RTF_STYLESHEET_FILE    =
+RTF_EXTENSIONS_FILE    =
+RTF_EXTRA_FILES        =
+#---------------------------------------------------------------------------
+# Configuration options related to the man page output
+#---------------------------------------------------------------------------
+GENERATE_MAN           = NO
+MAN_OUTPUT             = man
+MAN_EXTENSION          = .3
+MAN_SUBDIR             =
+MAN_LINKS              = NO
+#---------------------------------------------------------------------------
+# Configuration options related to the XML output
+#---------------------------------------------------------------------------
+GENERATE_XML           = NO
+XML_OUTPUT             = xml
+XML_PROGRAMLISTING     = YES
+XML_NS_MEMB_FILE_SCOPE = NO
+#---------------------------------------------------------------------------
+# Configuration options related to the DOCBOOK output
+#---------------------------------------------------------------------------
+GENERATE_DOCBOOK       = NO
+DOCBOOK_OUTPUT         = docbook
+#---------------------------------------------------------------------------
+# Configuration options for the AutoGen Definitions output
+#---------------------------------------------------------------------------
+GENERATE_AUTOGEN_DEF   = NO
+#---------------------------------------------------------------------------
+# Configuration options related to Sqlite3 output
+#---------------------------------------------------------------------------
+GENERATE_SQLITE3       = NO
+SQLITE3_OUTPUT         = sqlite3
+SQLITE3_RECREATE_DB    = YES
+#---------------------------------------------------------------------------
+# Configuration options related to the Perl module output
+#---------------------------------------------------------------------------
+GENERATE_PERLMOD       = NO
+PERLMOD_LATEX          = NO
+PERLMOD_PRETTY         = YES
+PERLMOD_MAKEVAR_PREFIX =
+#---------------------------------------------------------------------------
+# Configuration options related to the preprocessor
+#---------------------------------------------------------------------------
+ENABLE_PREPROCESSING   = YES
+MACRO_EXPANSION        = NO
+EXPAND_ONLY_PREDEF     = NO
+SEARCH_INCLUDES        = YES
+INCLUDE_PATH           =
+INCLUDE_FILE_PATTERNS  =
+PREDEFINED             =
+EXPAND_AS_DEFINED      =
+SKIP_FUNCTION_MACROS   = YES
+#---------------------------------------------------------------------------
+# Configuration options related to external references
+#---------------------------------------------------------------------------
+TAGFILES               =
+GENERATE_TAGFILE       =
+ALLEXTERNALS           = NO
+EXTERNAL_GROUPS        = YES
+EXTERNAL_PAGES         = YES
+#---------------------------------------------------------------------------
+# Configuration options related to diagram generator tools
+#---------------------------------------------------------------------------
+HIDE_UNDOC_RELATIONS   = YES
+HAVE_DOT               = NO
+DOT_NUM_THREADS        = 0
+DOT_COMMON_ATTR        = "fontname=Helvetica,fontsize=10"
+DOT_EDGE_ATTR          = "labelfontname=Helvetica,labelfontsize=10"
+DOT_NODE_ATTR          = "shape=box,height=0.2,width=0.4"
+DOT_FONTPATH           =
+CLASS_GRAPH            = YES
+COLLABORATION_GRAPH    = YES
+GROUP_GRAPHS           = YES
+UML_LOOK               = NO
+UML_LIMIT_NUM_FIELDS   = 10
+UML_MAX_EDGE_LABELS    = 10
+DOT_UML_DETAILS        = NO
+DOT_WRAP_THRESHOLD     = 17
+TEMPLATE_RELATIONS     = NO
+INCLUDE_GRAPH          = YES
+INCLUDED_BY_GRAPH      = YES
+CALL_GRAPH             = NO
+CALLER_GRAPH           = NO
+GRAPHICAL_HIERARCHY    = YES
+DIRECTORY_GRAPH        = YES
+DIR_GRAPH_MAX_DEPTH    = 1
+DOT_IMAGE_FORMAT       = png
+INTERACTIVE_SVG        = NO
+DOT_PATH               =
+DOTFILE_DIRS           =
+DIA_PATH               =
+DIAFILE_DIRS           =
+PLANTUML_JAR_PATH      =
+PLANTUML_CFG_FILE      =
+PLANTUML_INCLUDE_PATH  =
+PLANTUMLFILE_DIRS      =
+DOT_GRAPH_MAX_NODES    = 50
+MAX_DOT_GRAPH_DEPTH    = 0
+DOT_MULTI_TARGETS      = NO
+GENERATE_LEGEND        = YES
+DOT_CLEANUP            = YES
+MSCGEN_TOOL            =
+MSCFILE_DIRS           =
diff --git a/docs/adr/adr-0001-read-nato-data-with-csv-module.md b/docs/adr/adr-0001-read-nato-data-with-csv-module.md
new file mode 100644
index 0000000..cef74f6
--- /dev/null
+++ b/docs/adr/adr-0001-read-nato-data-with-csv-module.md
@@ -0,0 +1,53 @@
+# ADR-0001 Read the NATO data with the standard library csv module
+
+## Metadata
+| Key | Value |
+| --- | --- |
+| ID | ADR-0001 |
+| CrossReference | [BC-001], [SA-001] |
+
+## Version History
+| Date | Status | Author | Reviewer | Change | Commit |
+| --- | --- | --- | --- | --- | --- |
+| 2026-10-13 | Accepted | Jens Tirsvad Nielsen | AI as stand-in for S01 | Initial version, reviewed in RC-006 | pending |
+
+Allowed Status values: `Proposed`, `Accepted`, `Rejected`, `Deprecated`, `Superseded by ADR-NNNN`.
+
+---
+
+## Context
+
+The lecture reads the NATO alphabet file into a Pandas DataFrame and builds the dictionary with `iterrows`. The file has 26 rows and two columns. S01 follows the lecture, but S03 wants a repository with no runtime dependencies, and [BC-001] objective O5 and constraint "no runtime dependencies unless needed" say the same.
+
+Options evaluated:
+
+1. Pandas, as in the lecture: matches the course, but adds a large runtime dependency for a 26-row table.
+2. Polars: smaller than Pandas, still a runtime dependency that the task does not need.
+3. The standard library `csv` module: no dependency, and the dictionary comprehension that the assignment teaches works unchanged on the rows of `csv.DictReader`.
+
+## Decision
+
+Read the NATO alphabet with the standard library `csv` module (`csv.DictReader`) and build the letter-to-code-word dictionary with a dictionary comprehension. The project declares no runtime dependencies.
+
+## Consequences
+
+**Positive:**
+
+- No runtime dependency to install or keep secure; S03 sees an empty dependency list.
+- Faster start and a smaller environment for S02.
+- The comprehension taught in the lecture is still used.
+
+**Negative:**
+
+- The code differs from the lecture's Pandas code, so S02 comparing line by line sees a difference.
+- A later day that needs Pandas has to add it explicitly.
+
+## Affected Artifacts
+
+- [BC-001] — meets objective O5 and the constraint on runtime dependencies.
+- [SA-001] — resolves the conflict between S01 and S03 listed there.
+
+---
+
+[BC-001]: ../business-case.md
+[SA-001]: ../stakeholder-analysis.md
diff --git a/docs/adr/adr-0002-skip-analysis-artifacts.md b/docs/adr/adr-0002-skip-analysis-artifacts.md
new file mode 100644
index 0000000..9e25e66
--- /dev/null
+++ b/docs/adr/adr-0002-skip-analysis-artifacts.md
@@ -0,0 +1,50 @@
+# ADR-0002 Skip the optional analysis artifacts
+
+## Metadata
+| Key | Value |
+| --- | --- |
+| ID | ADR-0002 |
+| CrossReference | [BC-001] |
+
+## Version History
+| Date | Status | Author | Reviewer | Change | Commit |
+| --- | --- | --- | --- | --- | --- |
+| 2026-10-13 | Accepted | Jens Tirsvad Nielsen | AI as stand-in for S01 | Initial version, reviewed in RC-007 | pending |
+
+Allowed Status values: `Proposed`, `Accepted`, `Rejected`, `Deprecated`, `Superseded by ADR-NNNN`.
+
+---
+
+## Context
+
+The journey of the framework offers analysis documents beyond the baseline: KPI definitions, a Business Model Canvas, a BPMN process model and a riskiest-assumption test. The project is a single-evening course exercise with six measurable success criteria already in [BC-001], no commercial model, no business process and no costly belief to test.
+
+Options evaluated:
+
+1. Write all four documents: complete, but each needs a review and adds no decision that the Business Case does not already hold.
+2. Write only the KPI definitions: the success criteria would be restated in another file.
+3. Skip all four and record the reason here.
+
+## Decision
+
+Skip the KPI definitions, the Business Model Canvas, the BPMN process model and the riskiest-assumption test. The Business Case's Success Criteria table carries the measures, and the baseline documents (Business Case, Stakeholder Analysis, Project Plan, milestones) are not skipped.
+
+## Consequences
+
+**Positive:**
+
+- Less documentation to keep consistent for a small project.
+- The success criteria are stated once, in one place.
+
+**Negative:**
+
+- A reader who expects a KPI document finds the measures in the Business Case instead.
+- If the project grows (a package published, more users), the skipped documents must be written then.
+
+## Affected Artifacts
+
+- [BC-001] — its Success Criteria stay the only definition of the measures.
+
+---
+
+[BC-001]: ../business-case.md
diff --git a/docs/artifact-registry.md b/docs/artifact-registry.md
index 75393a8..b629482 100644
--- a/docs/artifact-registry.md
+++ b/docs/artifact-registry.md
@@ -1,59 +1,60 @@
-# Artifact Registry
-
-This project's artifact state. Types, short names and `CrossReference
-Candidates` come from the framework catalog
-(`framework/registry/artifact-catalog.md`); this file only records where
-each document lives in *this* project and the next version to use.
-
-Delete rows for types you don't use. Add a row the first time you create a
-document of a type. `Primary File` may contain a glob (e.g.
-`docs/uc-*/uc.md`); `framework/scripts/find-crossreferences.sh` reads it.
-
-| Short Name | Artifact Type | Primary File | Next Available Version |
-| --- | --- | --- | --- |
-| BC | Business Case | docs/business-case.md | 002 |
-| SA | Stakeholder Analysis | docs/stakeholder-analysis.md | 002 |
-| PP | Project Plan | docs/project-plan.md | 002 |
-| MIL | Milestone / Gateway | docs/milestones/*.md | 004 |
-| RC | SQA Review Record | docs/sqa/reviews/rc-*.md | 006 |
-| TM | Traceability Matrix | docs/sqa/traceability-matrix.md | 002 |
-
-## Languages
-
-Set the PO language when the project starts; `project-planning` asks for it
-if it is missing. An artifact of a type marked "Written in the PO language"
-exists once, in that language, under its normal name (`business-case.md`); the
-`artifact` skill ("One file per artifact") has the rule.
-
-| Setting | Value |
-| --- | --- |
-| PO language | en |
-| PO domain | it |
-| High-level register | IT Executive English |
-| Technical register | IT Professional English |
-
-Every artifact of a type marked "Yes" below states its language and domain in
-its `Language` and `Domain` Metadata rows; `new-artifact.sh` fills them from
-`PO language` and `PO domain`. `Language` is a BCP 47 code (`da`, `en`).
-`Domain` is a value from this list; add a row to introduce a domain, so a
-reviewer can see at once which professional vocabulary a document uses.
-
-| Domain | Meaning |
-| --- | --- |
-| it | Software and IT |
-| medical | Healthcare and medical devices |
-| construction | Construction and civil engineering |
-
-| Artifact types | Register | Written in the PO language |
-| --- | --- | --- |
-| BC, KPI, PP, MIL | IT Executive English | Yes |
-| SA, BMC, BPMN, UCD, US, UC, SSD, DM, RA, GOV, DICT | IT Professional English | Yes |
-| OC, SD, DCD, ERD, ADR, TM, RC, QC, source code | IT Professional English | No |
-
-## Notes
-
-- "Next Available Version" is the zero-padded (3-digit) version to use the
-  *next* time a new document of that type is created. Increment it only when
-  a brand-new document is created, not when an existing document's
-  `## Version History` gets a row.
-- `ADR` uses 4 digits (`0001`); `RC` is sequential across all artifact types.
+# Artifact Registry
+
+This project's artifact state. Types, short names and `CrossReference
+Candidates` come from the framework catalog
+(`framework/registry/artifact-catalog.md`); this file only records where
+each document lives in *this* project and the next version to use.
+
+Delete rows for types you don't use. Add a row the first time you create a
+document of a type. `Primary File` may contain a glob (e.g.
+`docs/uc-*/uc.md`); `framework/scripts/find-crossreferences.sh` reads it.
+
+| Short Name | Artifact Type | Primary File | Next Available Version |
+| --- | --- | --- | --- |
+| BC | Business Case | docs/business-case.md | 002 |
+| SA | Stakeholder Analysis | docs/stakeholder-analysis.md | 002 |
+| PP | Project Plan | docs/project-plan.md | 002 |
+| MIL | Milestone / Gateway | docs/milestones/*.md | 004 |
+| RC | SQA Review Record | docs/sqa/reviews/rc-*.md | 006 |
+| TM | Traceability Matrix | docs/sqa/traceability-matrix.md | 002 |
+| ADR | Architecture Decision Record | docs/adr/adr-NNNN-*.md | 0003 |
+
+## Languages
+
+Set the PO language when the project starts; `project-planning` asks for it
+if it is missing. An artifact of a type marked "Written in the PO language"
+exists once, in that language, under its normal name (`business-case.md`); the
+`artifact` skill ("One file per artifact") has the rule.
+
+| Setting | Value |
+| --- | --- |
+| PO language | en |
+| PO domain | it |
+| High-level register | IT Executive English |
+| Technical register | IT Professional English |
+
+Every artifact of a type marked "Yes" below states its language and domain in
+its `Language` and `Domain` Metadata rows; `new-artifact.sh` fills them from
+`PO language` and `PO domain`. `Language` is a BCP 47 code (`da`, `en`).
+`Domain` is a value from this list; add a row to introduce a domain, so a
+reviewer can see at once which professional vocabulary a document uses.
+
+| Domain | Meaning |
+| --- | --- |
+| it | Software and IT |
+| medical | Healthcare and medical devices |
+| construction | Construction and civil engineering |
+
+| Artifact types | Register | Written in the PO language |
+| --- | --- | --- |
+| BC, KPI, PP, MIL | IT Executive English | Yes |
+| SA, BMC, BPMN, UCD, US, UC, SSD, DM, RA, GOV, DICT | IT Professional English | Yes |
+| OC, SD, DCD, ERD, ADR, TM, RC, QC, source code | IT Professional English | No |
+
+## Notes
+
+- "Next Available Version" is the zero-padded (3-digit) version to use the
+  *next* time a new document of that type is created. Increment it only when
+  a brand-new document is created, not when an existing document's
+  `## Version History` gets a row.
+- `ADR` uses 4 digits (`0001`); `RC` is sequential across all artifact types.
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..7b58c7c
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,55 @@
+[build-system]
+requires = ["setuptools>=77"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "nato-alphabet"
+version = "0.1.0"
+description = "Console tool that spells a word with the NATO phonetic alphabet (100 Days of Code, day 26)."
+readme = "README.md"
+requires-python = ">=3.13"
+license = "AGPL-3.0-or-later"
+license-files = ["LICENSE"]
+authors = [{ name = "Jens Tirsvad Nielsen" }]
+keywords = ["nato", "phonetic-alphabet", "comprehensions", "100-days-of-code"]
+dependencies = []
+
+[project.optional-dependencies]
+dev = [
+    "pytest==9.1.1",
+    "ruff==0.17.0",
+    "mypy==2.4.0",
+    "import-linter==2.15",
+]
+
+[project.scripts]
+nato-alphabet = "nato_alphabet.main:main"
+
+[tool.setuptools.packages.find]
+where = ["src"]
+
+[tool.setuptools.package-data]
+nato_alphabet = ["data/*.csv"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+pythonpath = ["src"]
+
+[tool.ruff]
+line-length = 88
+src = ["src", "tests"]
+extend-exclude = ["framework", ".agents", ".claude"]
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "N", "UP", "B", "D"]
+
+[tool.ruff.lint.pydocstyle]
+convention = "pep257"
+
+[tool.ruff.lint.per-file-ignores]
+"tests/**" = ["D"]
+
+[tool.mypy]
+strict = true
+files = ["src", "tests"]
+mypy_path = "src"
diff --git a/src/nato_alphabet/__init__.py b/src/nato_alphabet/__init__.py
new file mode 100644
index 0000000..d823b9a
--- /dev/null
+++ b/src/nato_alphabet/__init__.py
@@ -0,0 +1 @@
+"""@brief Console tool that spells a word with the NATO phonetic alphabet."""
diff --git a/src/nato_alphabet/constants.py b/src/nato_alphabet/constants.py
new file mode 100644
index 0000000..296a858
--- /dev/null
+++ b/src/nato_alphabet/constants.py
@@ -0,0 +1,29 @@
+"""@brief Constants of the NATO alphabet tool.
+
+Every literal that the program, its messages or its data loading depend on is
+defined here once.
+"""
+
+## @brief Name of the package that holds the data file.
+DATA_PACKAGE: str = "nato_alphabet"
+
+## @brief Folder inside the package that holds the data file.
+DATA_DIRECTORY: str = "data"
+
+## @brief Name of the comma-separated values file with the NATO alphabet.
+DATA_FILE_NAME: str = "nato_phonetic_alphabet.csv"
+
+## @brief Header of the column with the letter in the data file.
+LETTER_COLUMN: str = "letter"
+
+## @brief Header of the column with the code word in the data file.
+CODE_COLUMN: str = "code"
+
+## @brief Text shown when the program asks for a word.
+PROMPT_TEXT: str = "Enter a word: "
+
+## @brief Text shown when the word holds a character that is not a letter.
+INVALID_INPUT_TEXT: str = "Sorry, only the letters A to Z are allowed. Try again."
+
+## @brief Text shown before the code words are printed.
+RESULT_TEXT: str = "Phonetic code words:"
diff --git a/src/nato_alphabet/data/nato_phonetic_alphabet.csv b/src/nato_alphabet/data/nato_phonetic_alphabet.csv
new file mode 100644
index 0000000..3d8e6d8
--- /dev/null
+++ b/src/nato_alphabet/data/nato_phonetic_alphabet.csv
@@ -0,0 +1,27 @@
+letter,code
+A,Alfa
+B,Bravo
+C,Charlie
+D,Delta
+E,Echo
+F,Foxtrot
+G,Golf
+H,Hotel
+I,India
+J,Juliet
+K,Kilo
+L,Lima
+M,Mike
+N,November
+O,Oscar
+P,Papa
+Q,Quebec
+R,Romeo
+S,Sierra
+T,Tango
+U,Uniform
+V,Victor
+W,Whiskey
+X,X-ray
+Y,Yankee
+Z,Zulu
\ No newline at end of file
diff --git a/tests/test_package.py b/tests/test_package.py
new file mode 100644
index 0000000..0ba0135
--- /dev/null
+++ b/tests/test_package.py
@@ -0,0 +1,29 @@
+"""Smoke tests of the package skeleton."""
+
+from importlib import resources
+
+from nato_alphabet import constants
+
+EXPECTED_ROW_COUNT = 26
+
+
+def test_data_file_exists_in_package() -> None:
+    data_file = (
+        resources.files(constants.DATA_PACKAGE)
+        / constants.DATA_DIRECTORY
+        / constants.DATA_FILE_NAME
+    )
+
+    assert data_file.is_file()
+
+
+def test_data_file_has_one_row_per_letter() -> None:
+    data_file = (
+        resources.files(constants.DATA_PACKAGE)
+        / constants.DATA_DIRECTORY
+        / constants.DATA_FILE_NAME
+    )
+
+    lines = data_file.read_text(encoding="utf-8").splitlines()
+
+    assert len(lines) - 1 == EXPECTED_ROW_COUNT