chemenu/instructions/dev/stack-dev/SKILL.md

---
name: stack-dev
description: Switch a session into tool-development mode - extending tools/wikitool, the compiler, the type schema, or the instruction/skill layer itself, instead of operating on wiki content. Use when the user asks to add a wikitool command, change a type-spec, fix or extend the compiler, or otherwise work on the stack rather than ingest/query/manage/lint the wiki.
---

# Stack Development Mode

**Purpose:** Recognize a session that is about the tool stack itself - `tools/wikitool`, the
type schema, the instruction/skill layer - rather than wiki content, and switch the rules that
apply accordingly.

**Trigger:** The user asks to add or change a `wikitool` command, extend the compiler, change a
type-spec, or work on `instructions/`/`types/`/`tools/` as code rather than as a place to run
`wiki-ingest`/`wiki-query`/`wiki-manage`/`wiki-lint`/`wiki-status` against.

**This directory is dev-only.** `instructions/dev/` is excluded wholesale by
`tools/wikitool dist export` - nothing here ever reaches a distributed instance, and there is
no restore path. If you are in a distributed instance, this skill should not be present at all;
stack development happens in the origin repo instead (see AGENTS.md's routing line).

## What changes in this mode

- **Source-binding does not apply to code.** AGENTS.md invariant 3 ("never file an unsourced
  answer into the wiki") governs `kb/` content, not the code you write to extend the stack.
  Ordinary software-engineering judgment applies to `tools/chemenu/*.py`, `types/*`,
  `instructions/*` - it does not need a `raw/` source or a citation.
- **Test and review conventions from `instructions/dev/` apply instead**, once written down
  there (step 2 below lists what currently exists). Until a given convention has its own
  instruction file, follow the existing test files' own patterns
  (`tools/chemenu/tests/`) rather than inventing a new one silently.
- **Everything outside this directory still applies.** The tool error contract, the gates, and
  "never hand-edit generated files" (AGENTS.md invariants 1, 5-8) are about how the tool
  behaves at runtime, not about developing it, but they still bind normal session conduct
  (e.g. still use `tools/wikitool publish`, still respect the gates, when the session also
  touches wiki content).

## Steps

1. **Confirm the mode.** If the task is ambiguous between "extend the tool" and "operate the
   wiki", ask rather than guess - the two have different rules for the same directories.
2. **Consult `instructions/dev/` for the concrete procedure.** Currently:
   [commonplace-kb.md](../commonplace-kb.md) - vendored knowledge base on agent context
   engineering, memory and deploy-time learning; consult before a design decision in those
   areas.
   [issue-tracking.md](../issue-tracking.md) - open work lives in Gitea issues, one per work
   package, labelled `area/`, `kind/`, `prio/` and `size/`. There is no `TODO.md`. **The body
   of the issue you are working on is this session's plan file:** keep it current as the state
   moves, so an interrupted session leaves a body the next one can resume from, *and* rewrite it
   to its final state before closing. Both halves bind; the second is what
   [`stack-close`](../stack-close/SKILL.md) carries out once this skill's own work is published -
   see step 5 below. Read it before filing something for later, before editing or closing an
   issue, or before deciding what to pick up next.
   [testing-conventions.md](../testing-conventions.md) - the suite runs against a deliberately
   empty machine; what the autouse fixture already neutralizes, and what a test still has to
   establish itself. Read it before adding or changing a test.
   [version-parts.md](../version-parts.md) - which part a change bumps: the drop-in test, the
   catalogue of breaks that cross the compatibility boundary with `kb/` untouched, and what to
   put in front of the user before a breaking bump. Read it before step 4.
   [corpus-policy.md](../corpus-policy.md) - what "curated enough" means for the shared
   demo/testbed `kb/`, the measurable floors that define it, and what a reactive fix may and may
   not do to corpus content. Read it before judging whether the corpus can exercise a change, or
   before any fix that would touch `kb/` content.
   More instructions are added here incrementally as stack-development needs come up - this
   list grows without needing this skill file to change shape.
3. **Settle the design before building - and break there for the model switch.** These are two
   different kinds of work, and the split is not stylistic: design, the version part and any
   boundary judgment have **no** mechanical guard, while the code and tests that follow are mostly
   covered - `pytest`, `docs verify`, `instructions verify` and CI catch a mistake **in what they
   cover**.

   So when the design is settled - the issue body says what will be built, the open questions are
   answered - stop and say so, in one sentence that names what the mechanical stretch does **not**
   cover:

   > Der Plan steht, ab hier ist die Arbeit größtenteils mechanisch und durch Tests/CI abgedeckt -
   > mit Ausnahme der Changelog-Prosa (Schritt 4), einer berührten `docs/`-Seite, neuer
   > Menschendoku oder des Prosa-Anteils einer Instruction. Wenn du auf Opus bist, ist jetzt der
   > Moment für `/model sonnet` bei Effort `high`.

   **You cannot make this switch yourself** - the session's model is the user's `/model`, not a
   setting an agent applies. Offer it once and keep working either way; a session that argues
   about its own model has already cost more than the difference. If the design turns out not to
   be settled after all - a boundary crossing surfaces, an assumption breaks - that is a reason to
   offer the switch back up, not to decide it alone.

   **"Covered by tests" means covered by the tests that exist, not by the tests that should
   exist.** Whether the right test was written is itself a judgment call with no mechanical
   guard: two data-destroying bugs in `upstream merge` (Gitea #30) shipped past a green
   `pytest`/`docs verify`/`instructions verify`/CI because no test exercised the case, not
   because a weaker model wrote worse code for the case that *was* tested. This is not a third
   break - it is a caveat on this one: the middle phase stays the cheaper phase to run on, but its
   test suite is only as complete as the judgment that wrote it, and that judgment is unchecked
   the same way the design phase is.

   Effort is the cheaper lever than the model, and `high` is the floor for anything touching more
   than one file or a contract. Full table and reasoning:
   [claude-code-model-selection.md](../../claude-code-model-selection.md).

4. **Raise the version, if the change ships.** A change under `tools/`, `types/`,
   `instructions/`, `AGENTS.md` or a `CONTRACT.md` reaches every future instance, so it needs a
   version and a changelog entry:

   ```bash
   tools/wikitool version bump --patch --title "<what changed>"
   ```

   Never edit `VERSION` or the entry's heading by hand - `bump` writes both, and `docs verify`
   fails a tree where they disagree. Pick the part by whether the new version is a **drop-in
   replacement** for the old one - not by whether content has to be migrated:

   | Change | Part |
   |--------|------|
   | Fix, no interface change | `--patch` |
   | New capability, still drop-in in both directions | `--minor` |
   | **Not a drop-in replacement** - any hand-work by the user or a migration script, or a downgrade that no longer works | `--major` |

   Content migration is one way to land in the last row, not the definition of it: a rename of
   the update path, the artefact, an import name, a flag or an envvar breaks a swap with `kb/`
   entirely untouched. The full test, the catalogue of such breaks, and what to put in front of
   the user first are in [version-parts.md](../version-parts.md) - **read it before choosing
   `--major`.**

   A `--major` bump therefore needs two things recorded. `--breaking "<what stops working>"`
   is required on every boundary-crossing bump; on top of it, a migration document for the new
   version - written per [migrate-corpus.md](../../migrate-corpus.md) - or
   `--no-migration "<reason>"` when no content actually has to change. `bump` refuses without
   either, and so does `docs verify`: an instance learning that it must migrate, with nothing
   telling it how, is a dead end.

   Then write the entry's body - `bump` deliberately leaves it empty, the same way `new` leaves
   the prose.

   Prose-only changes (`README.md`, `INSTALL.md`, `EVALS.md`) and the workflows under `.gitea/`
   do not need a bump - CI's version gate is scoped to what changes behaviour.

5. **Verify, then publish.** `tools/wikitool docs verify`, `tools/wikitool instructions verify`,
   and the relevant `pytest` run in `tools/` - the same checks any stack change must pass, run
   explicitly rather than assumed. CI (`.gitea/workflows/ci.yml`) runs these plus a full
   `setup-instance.md` replay against a fresh `dist export`; a push to `main` that moves `VERSION`
   additionally triggers a tagged release. **CI does the tagging** - a session never creates a
   tag, which is what keeps AGENTS.md invariant 5 intact.

   Publish with `tools/wikitool publish`. When the changeset touches `tools/`, `types/`,
   `instructions/`, `AGENTS.md` or a `<stage>/CONTRACT.md`, `publish` itself prints a one-line
   reminder that the phase past this point is not covered by any of the checks above - that line
   is the cue that this skill's own job just ended.

   **This skill stops here.** The closing phase - rewriting the issue body to its final state,
   checking for `docs/` staleness, and naming which model ran which phase of the session - lives
   in [`stack-close`](../stack-close/SKILL.md), not in a further step of this one. Invoke it now;
   do not fold its work into this session under this skill's rules, and do not treat "the change
   is published" as this work package being done.

## Decision points

- **Touches both stack code and wiki content in one session?** Apply this skill's rules to the
  code changes and the normal content skills' rules to the content changes - they are not
  mutually exclusive within a session, only per change.
- **The change turns out not to be a drop-in replacement?** Do not bump across the boundary on
  your own initiative. Every existing instance pays for a breaking change once, by hand, so the
  user decides whether it is worth that: show them what breaks, what an instance has to do about
  it, and the alternatives (avoid the break with a shim, defer and batch it with the next one,
  or split it behind a deprecation window), then recommend one and wait for a go-ahead.
  [version-parts.md](../version-parts.md) step 4 has the full shape. A surfacing boundary crossing
  is also a reason to offer the model switch back up (step 3): the judgment it needs has no
  mechanical guard, and `docs verify` only checks that a crossing documents itself, never that the
  part was chosen correctly.

## Scope

Not for wiki content work - use `wiki-ingest`/`wiki-query`/`wiki-manage`/`wiki-lint`/
`wiki-status` for that. Not for setting up a new instance (`instructions/setup-instance.md`) or
a fresh clone of this repo (`instructions/bootstrap.md`). Not for closing a work package after
its publish has landed - that is [`stack-close`](../stack-close/SKILL.md).