chemenu/tools/README.md

# tools/

Developer documentation for `wikitool` - how the CLI is built, how to change it,
and how to run its tests.

**This is not the command reference.** That is [CONTRACT.md](CONTRACT.md), which
`wikitool docs verify` checks against the registered commands. Copying its
generated command records here would create a second copy that drifts, so this
file deliberately has none - and `docs verify` now enforces that.

| Document | Audience |
|---|---|
| `README.md` (this file) | Humans working *on* wikitool |
| [`CONTRACT.md`](CONTRACT.md) | Agents working *with* wikitool - commands, error contracts, maintenance schedule |
| [`../AGENTS.md`](../AGENTS.md) | The invariants that say when using a command is mandatory |
| [`../CHANGES.md`](../CHANGES.md) | What changed in the stack, and when |

## Setup

```bash
tools/preflight.sh      # from the repo root
```

```powershell
pwsh -NoProfile -ExecutionPolicy Bypass -File tools/preflight.ps1   # PowerShell 7 on Windows
```

The preflight is the one way a checkout gets its environment: it checks the
tools listed in `prerequisites.txt`, records their absolute paths in
`../.wikitool-tools.json`, creates `.venv` and installs `requirements.txt` into
it with `-m pip`. It is POSIX sh because it has to run before Python is known
to exist; exit 42 means the user has to act, and its output says how. The
procedure an agent follows around it is `instructions/preflight.md`.

Each release also attaches `preflight.sh` and `preflight.ps1` as assets, for the first install
before any tree exists. `release.yml` writes the download address of that same release into two
placeholder lines of the copy (`RELEASE_ARCHIVE_URL`/`RELEASE_CHECKSUM_URL` in the shell script,
`$ReleaseArchiveUrl`/`$ReleaseChecksumUrl` in the PowerShell one; the tree copy leaves them
empty). With no `prerequisites.txt` beside it, the script is in *asset mode*: it downloads the
tarball and its `.sha256`, refuses on a mismatch, reads the folder limit out of the archive,
unpacks into `<script folder>/chemenu` (`--into <path>` to choose, an existing target is refused),
and runs the tree copy of itself, passing `--set` and its exit code through. `--archive <tarball>`
takes a local tarball instead of a download (its `.sha256` has to lie next to it); that is also
how the tests drive it.

`tools/wikitool` refuses to start (exit 42) until the preflight has written a
*complete* `.wikitool-tools.json` and the venv exists. Past that, every `git`
and `rg` the package starts goes through `chemenu/toolpaths.py`, which reads
the recorded path - or, with no file at all (the test suite, a bare
`python -m chemenu.cli`), falls back to the bare name. A file that is present
but names a path that has gone raises `ToolPathError`, which the CLI turns
into an `ERROR` line pointing at the preflight rather than a traceback.

The package runs natively on Windows as well, which CI never does. So the rules that keep
it portable are held by reading the source, in the origin repository's `tests/test_portability.py`: a path that
becomes a string goes through `.as_posix()`, a text file is opened with `encoding=` and
written with `newline="\n"`, a `subprocess` call with `text=True` names `encoding="utf-8"`,
and only `filelock.py` imports `fcntl` or `msvcrt`. An `rg` path comes back with `\` on
Windows even with `--path-separator /`, so `search/ripgrep.py` converts it where it parses
the JSON. `.gitattributes` keeps every text file LF in a checkout, `raw/` and `incoming/`
excepted.

`jsonschema` and `PyYAML` are hard dependencies, not optional extras: schema
validation is the tool's whole safety net, so `cli.py` fails loudly with the
fix rather than degrading silently.

## Layout

```
tools/
  wikitool                 entry point (POSIX sh): stops with exit 42 until the preflight has passed
  wikitool.ps1             the same entry point for PowerShell 7, which resolves `tools/wikitool` to this file first
  run_wikitool.py          what the launcher runs with the venv's Python - puts chemenu on sys.path without PYTHONPATH, sets stdout/stderr to UTF-8
  preflight.sh             checks prerequisites.txt, records .wikitool-tools.json, creates .venv (POSIX sh); as the release asset, downloads the stack and unpacks it into its own (empty) folder first
  preflight.ps1            the same for PowerShell 7; also checks the execution policy and the Mark of the Web
  prerequisites.txt        what the machine needs, one `|`-separated line per tool - read by the preflight and `doctor`
  trace-hook               what the harness hooks call: trace_ingest.py under the venv's Python
  trace-hook.ps1           the same for PowerShell, which resolves `./tools/trace-hook` to this file first - without it Windows asks which app opens the sh script
  bugreport                entry point for the bug-report collector (POSIX sh): finds a Python 3.8+ on PATH itself, skipping the Microsoft Store aliases, and runs bugreport.py - no preflight needed
  bugreport.ps1            the same for PowerShell, which resolves `tools/bugreport` to this file first; keeps to what Windows PowerShell 5.1 understands
  bugreport.py             the bug-report collector itself - see below
  chemenu/
    cli.py                 Typer app: registers every command, runs the budget gate, renders `-h`/`--help` from cli_contract
    cli_contract.py         one data record per command (name, synopsis, properties, exit status) - the source `-h`, the index and CONTRACT.md's generated region render from
    config.py              repo layout: root resolution and every path under it
    api.py                 the in-process entry point - point Chemenu at a corpus and read it
    errors.py              ChemenuError / ValidationError / BackendError
    toolpaths.py           where git and rg are started from: .wikitool-tools.json, bare name only without the file
    filelock.py            an exclusive lock on an open file, flock on POSIX and msvcrt on Windows - the only module that imports either
    prerequisites.py       prerequisites.txt read from Python, plus the platform and long-path questions `doctor` asks
    install_doc.py         INSTALL.md held to the instructions: its prerequisites lists generated from prerequisites.txt, its setup questions matched to setup-instance.md's markers
    corpus_cache.py        one parsed corpus per commit, never cached while the tree is dirty
    kb_scan.py             page iteration/loading over kb/
    blocks.py              generated regions in a page body, found by marker rather than by heading
    links.py               labelled edges in `related:` - the graph's semantics as data, not prose
    kb_collections.py      collection discovery (a directory with COLLECTION.md), and what one declares about itself
    conventions.py         kb/CONVENTIONS.md: what this instance decided about authoring, as opposed to what the stack enforces
    ownership.py           the stack-vs-instance boundary under a content stage - one predicate, so no caller keeps a list of its own
    type_resolver.py       type-spec loading and schema resolution
    catalog.py             how the corpus groups into collections and areas, and the shard threshold - with no CLI attached
    lint_core.py           the lint checks and the report, with no CLI attached
    types_core.py          type-spec listing/description, with no CLI attached
    review.py              the weekly review's five checks - the read-time join of kb/gtd/ against the tracker, with no CLI attached
    markdown_code.py       masks code spans/fences so a page may show wiki notation, not only use it
    version.py             the stack version: VERSION, the release stamp, the compatibility rule
    kb_state.py            the KB version (.wikitool-kb.json) and the migration chain
    corpus_diff.py         invariant comparison of kb/ between two revisions
    web_capture.py         `raw fetch`'s core: fetch a page, decide its charset, derive Markdown-like text from the HTML - standard library only, deterministic
    repo_capture.py        `raw capture`/`raw status`'s core: resolve a ref rule, fetch it into a bare cache, select files by glob as blobs, the `_capture.json` manifest - git with the host's credentials, never a prompt
    search/                pluggable search backends, plus service.py - the search core
    tasks/                 the task-tracker provider layer: protocol.py (TaskReader/TaskWriter), config.py (.wikitool-tasks.json), one module per adapter - no instruction ever learns which provider it is
    commands/              one module per command or command group: the terminal adapters
    tests/                 pytest suite - origin repository only, `dist export` leaves it out
```

**A script beside the package.** `bugreport.py` is not part of `chemenu` and imports nothing
from it: it is the bug-report collector ([../instructions/bug-report.md](../instructions/bug-report.md)),
and the case it exists for is a checkout where `wikitool` does not start. It therefore uses the
standard library only, keeps to Python 3.8 syntax so that an old interpreter can still run it, and
exits 0 or 1 - never 42, since it opens no gate. It has a second mode: `--pseudonymise` replaces the
identities it can read from the machine (stage 1), and `--bundle`/`--candidates` applies names a
model found in the result (stage 2), both word by word so that length, separators and depth
survive. The mapping, the review list and the candidate file stay beside the bundle directory.
`dist export` ships it with the rest of `tools/`;
its tests (`tests/test_bugreport.py`, in the origin repository) run it on a bare interpreter (`-I -S`) to keep that promise.

It is started through `tools/bugreport` (`bugreport.ps1` under PowerShell), which assumes no more
than the collector does: no preflight, no `.wikitool-tools.json`, no venv. It looks for the
interpreter the way the preflight does - `python3`, `python` on `PATH`; on Windows `python`,
`py -3`, `python3` - then tries the venv's, probes each for 3.8 or newer, and never starts one under
`WindowsApps`, where `python3` in Git Bash is the Microsoft Store's alias. Finding none, it exits 1
and says why.

**Two consumers, one core.** The CLI is not the only caller any more. The cores
(`search/service.py`, `lint_core.py`, `types_core.py`, `catalog.py`) hold what
decides an answer and import no `typer` and no `rich`; the modules under `commands/` turn
those values into terminal output and those exceptions into exit codes.
`api.Corpus` is the in-process entry point over the same functions - it takes a
corpus root, returns exactly the structures the `--json` forms print, and
raises instead of exiting. A second consumer is therefore a second adapter
rather than a second implementation, and the write commands are unreachable
from `api` because nothing under `commands/` is imported there.

**Which corpus.** The root resolves by precedence: an explicit argument, then
`$CHEMENU_ROOT`, then a walk up from the package's own location. The walk-up is
the default, so the CLI is unaffected by any of this. Nothing under the root is
bound at import time - `KB_DIR` and friends follow whatever `ROOT` currently is.

## Adding a command

1. Write the module under `chemenu/commands/`. A group is a `typer.Typer()`
   app; a single command is a plain function.
2. Register it in `cli.py` (`app.add_typer(...)` or `app.command(...)`).
3. Attach a `@cli_contract.record(cli_contract.CommandRecord(...))` decorator to
   the command function, in its own module, and add its path to the matching
   group in `cli_contract.GROUPS`. That one record is the source `wikitool
   <cmd> -h`, the index (`wikitool -h`, and the top of
   [CONTRACT.md](CONTRACT.md)), and CONTRACT.md's generated `#### <path>`
   section all render from - see `cli_contract.py`'s own module docstring for
   the record's shape, and the `CommandRecord` docstring for how its prose is
   written (NOTES as present-tense bullets, one `Failure` per cause with its
   reaction, copyable EXAMPLES, NEVER, SEE ALSO, and no "why" - that goes into
   a comment next to the code). `docs verify` fails in both directions - a command with
   no record and a `GROUPS` entry naming no real command are equally reported -
   and also checks that every non-hidden flag appears in the record's SYNOPSIS.
   Then regenerate the copy: `wikitool docs contract --apply`. Write the
   record's prose without citing an issue number: `docs verify` also refuses
   one in a command's rendered `--help` text (a docstring above its `\f`
   marker, or an option's `help=`) and in any `.md`/`.template` `dist export`
   ships, because the tracker exists only in this repo
   (`instructions/dev/issue-tracking.md` § Citing an issue in the repo).
4. Add tests. Pure logic belongs in a function separate from the Typer callback
   (see `mass_update_gate_message`, `derive_run_key`, `run_export`), so a test
   does not need a CLI runner - and a Typer callback called directly from a test
   receives `OptionInfo` objects, not values, for any argument the test omits.
5. Raise the version: `wikitool version bump --minor --title "..."` for a new
   command (`--patch` for a fix, `--major` when the new version is **not a
   drop-in replacement** - a renamed flag or artefact, a stricter check that
   newly fails on **shipped content an instance already had** (a `kb/` page,
   an `instructions/*.md` file), anything needing hand-work after the copy).
   A new command that is merely pickier about its *own* fresh input - a flag
   it did not previously accept, a write it now refuses without more from the
   caller - is the ordinary MINOR case: nothing an instance already has stops
   validating, there is simply more to say when the command is next invoked.
   Content migration is one way to land in the MAJOR row, not the definition
   of it: a `--major` may well ship `--no-migration`, and one that does
   migrate also needs a document under `instructions/migrations/`. The full
   test is `instructions/dev/version-parts.md` - read it before choosing
   `--major`.
   A new command reaches every future instance, and CI's version gate refuses a
   stack change that moved no version.

Every command is counted against the iteration budget unless its `cli_contract`
record's `budget:` property says `exempt` (or, for `version regrade`'s own
shape, `exempt_without_args`) - `run_budget.is_exempt` reads it from there,
not from a list of its own. Only read-only retrieval earns it.

## Design notes

**Deterministic by default.** Anything an LLM would otherwise re-derive -
frontmatter, index statistics, cross-reference bookkeeping, log formatting,
version arithmetic - is computed here so it comes out the same every time.

**Gates are code, not prompts.** The Mass-Update Gate (`git_publish.py`) and the
Iteration Budget Gate (`run_budget.py`) refuse in-process, because a
prompt-level limit is one an agent can talk itself past. Exemption lists are
constants, never flags.

**Clearance is an exit code, not an instruction.** `EXIT_NEEDS_CLEARANCE`
(42, in `commands/_util.py`) is a third outcome beside success and validation
error, meaning "a human has to see this output first". The command's own
message carries the reason, the evidence and the exact `--confirm <token>`
re-run line; the instruction layer deliberately holds none of it, because a
procedure written down in advance is one an agent can complete alone. Whether
a human *actually* saw it is not enforced here - that question is answered in
the eval layer (`evals/trajectory.py`, `clearance-ended-the-turn`).

**Nothing locates a region by its prose.** `xref` owns the links region and `cite` the footnotes
region, and each is delimited by a `<!-- wikitool:<name> -->` marker pair (`blocks.py`). The
heading inside is rendered from `kb/CONVENTIONS.md` and is replaced along with the rest of the
region on every write - so no heading text exists in Python, and changing the declaration cannot
split a page.

Both halves of that mattered. Matching on the heading made the KB language a compiler constant;
*guessing* where the region ended - at the next heading, and before that at the end of the file -
silently deleted content sitting after it on eight pages. `migrate verify` compares marker-pair
counts for the same reason it compares wikilink counts: a dropped marker is invisible otherwise.

**A relationship label is data, not prose.** `related:` carries `- <label>: <target>`
(`links.py`), the label drawn from `instructions/link-taxonomy.md` and authorised per
destination by the *source* collection's `outbound:` block. The body bullet is a rendering of
that, which is what removed the need to parse a German phrase back into a relationship - and why
the vocabulary can be checked at all, after drifting to 152 distinct labels while it could not
be. Both readers accept a bare title as an unlabelled edge: that is the shape a page is in
between the machinery landing and the migration reaching it, and `lint` is what reports it.

**An edge is authored in one direction.** `xref add` writes one, on the asserting page. The
inbound view is rendered from the graph rather than stored, so navigation does not depend on
anyone writing a mirror - and per-collection authorisation stays coherent, which it cannot be if
the tool writes edges into a collection whose rules the author never read.

**Generated output is never committed.** `reports/`, `.agents/skills/` and
`.claude/skills/` are build output; `docs verify` carries canaries in both
directions so an ignore rule can neither swallow tracked content nor stop
ignoring generated copies.

<!-- dist:strip-start -->
## Tests

The suite exists in the origin repository only: `dist export` leaves out `chemenu/tests/`,
`pytest.ini` and `.coveragerc`, because the suite tests that repository's own type-specs and
conventions, not an instance's.

```bash
cd tools && .venv/bin/python -m pytest -q
```

`pytest.ini` sets the import path. Tests use `tmp_path` fixtures and monkeypatch
`config` paths rather than touching the real `kb/`.

Coverage is optional locally and measured on every CI run:

```bash
.venv/bin/pip install pytest-cov   # one time, CI-only dependency
.venv/bin/python -m pytest -q --cov
```

`pytest-cov` is deliberately not in `requirements.txt`: that file is what an *instance*
needs at runtime and ships with `dist export`, and an instance does not measure this
suite. Configuration is `.coveragerc` (coverage.py does not read `pytest.ini`), which
measures `chemenu/` without `chemenu/tests/` and sets no threshold - see EVALS.md
for the measured number and how to read it.

**Two exceptions, and they bite.** `test_types_cmd.py` and `test_index_build.py` resolve the real
`types/` through the shared `resolver`, because what they assert *is* that behaviour comes from the
type-specs rather than from a hardcoded map. Editing a type-spec can therefore fail tests that look
unrelated to it - translating the wiki broke six that way. Anything those tests pin must be
structural: `dir:` values and layout order are asserted exactly, display titles are read from the
spec at assert time, never written out. The same rule applies to the template fence - anchor on a
section name from `sections`, not on a literal.

Assert on prose in a type-spec or a contract only when the prose is the subject of the test.
Otherwise it is a tripwire that fires on an edit nobody connected to the test.
<!-- dist:strip-end -->