fix(mcp): correct the parked reason — the tokens work, the delivery does not

The previous note blamed infra#224 for cad and gitea-mcp being unreachable.
Both claims were wrong. infra#224 is closed, and closed deliberately: rather
than widening koala-homelab's grants, a second scoped token was provisioned at
~/.op-agent-write.env for AgentSecrets. Sourcing it makes `op vault list`
return AgentSecrets, and an MCP initialize against both endpoints returns 200 —
serverInfo gitea-mcp 0.1.0 and cad aed2aaf. Nothing about the services or the
proxying is blocked.

What is actually blocked is delivery into the session environment. By design no
single identity on koala reads both vaults, and the session env comes from one
`op run --env-file ~/.op-env` under the HomeLab-only token. A mixed-vault file
does not degrade gracefully: tested on a two-line copy, `op run` aborts on the
unresolvable reference and BRAIN_MCP_TOKEN goes unresolved with it — so
appending to ~/.op-env would take out the MCP servers that currently work.

Refs #32, #33
Bump-Type: patch

.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "skills",
   "description": "Mathias's engineering skills library, plus the hooks and MCP servers that make it enforceable: TDD, clean code, debugging, specs, discovery, CI, and secret hygiene.",
-  "version": "0.10.2",
+  "version": "0.13.1",
   "author": {
     "name": "Mathias",
     "url": "https://git.d-ma.be/mathias"

.mcp.json

@@ -12,5 +12,22 @@
       "type": "http",
       "url": "https://koala.tail30472e.ts.net:8444/mcp"
     }
+  },
+  "_parked": {
+    "_reason": "cad and gitea-mcp are proxied, reachable and AUTHENTICATING: tailscale serve 8445 -> 127.0.0.1:31877 and 8446 -> 127.0.0.1:30340; an MCP initialize with the correct bearer returns 200 from both (serverInfo gitea-mcp 0.1.0, cad aed2aaf). They stay parked only because nothing puts those two tokens into the session environment. Both live in the 1Password AgentSecrets vault, and by deliberate design (infra#224, closed) no single identity on koala reads both vaults: koala-homelab is HomeLab-only and resolves ~/.op-env, koala-agentsecrets-write is AgentSecrets-only and lives in ~/.op-agent-write.env. Adding an AgentSecrets reference to ~/.op-env does NOT degrade gracefully -- `op run` fails wholesale and every other token, BRAIN_MCP_TOKEN included, goes unresolved with it. Enabling needs a read-scoped AgentSecrets identity in the session-env path; see mathias/skills#32, #33.",
+    "cad": {
+      "type": "http",
+      "url": "https://koala.tail30472e.ts.net:8445/mcp",
+      "headers": {
+        "Authorization": "Bearer ${CAD_MCP_TOKEN}"
+      }
+    },
+    "gitea": {
+      "type": "http",
+      "url": "https://koala.tail30472e.ts.net:8446/mcp",
+      "headers": {
+        "Authorization": "Bearer ${GITEA_MCP_STATIC_TOKEN}"
+      }
+    }
   }
-}
+}

skills/clean-code/SKILL.md

@@ -281,5 +281,6 @@ During refactoring:
 
 - `references/clean-code.md` — detailed naming rules, object calisthenics
 - `references/code-smells.md` — comprehensive smell catalog with examples
+- `references/python-adaptation.md` — Python conventions: error chaining, dataclasses, the truthiness trap
 - Load `solid` skill for SOLID principles with Go examples
 - Load `refactoring` skill for systematic refactoring techniques

skills/clean-code/references/python-adaptation.md

@@ -0,0 +1,104 @@
+# Clean Code: Python Adaptation
+
+The principles in `SKILL.md` are language-agnostic. This file covers the places where
+Python's idioms differ from the Go examples, and where following the Go shape produces
+bad Python.
+
+The canonical stack (ruff, mypy --strict, pytest, uv, pydantic-settings, src-layout)
+lives in `~/dev/.context/AGENT.md` and is not restated here — one source of truth, and
+it is not this file.
+
+## Reveal intent with types, not comments
+
+`mypy --strict` is the Python analogue of Go's compiler, and it is non-negotiable for
+the same reason: a type is a claim the machine checks, and a comment is a claim nobody
+checks. Two consequences for clean code specifically:
+
+- **`Any` is a hole in the argument.** Each one says "the reader is on their own here".
+  If a value is genuinely polymorphic, say so precisely — `Protocol`, a union, a
+  `TypeVar` — rather than surrendering.
+- **A `# type: ignore` needs the error code and a reason**: `# type: ignore[arg-type]  #
+  boto3 stubs lag the API`. A bare ignore is an unexplained exception to a rule the rest
+  of the file follows.
+
+## Errors: chain them, never swallow them
+
+Go's `fmt.Errorf("operation: %w", err)` is `raise` with `from`:
+
+```python
+# Bad — the original cause is gone, and so is the stack that produced it
+try:
+    row = fetch(invoice_id)
+except KeyError:
+    raise InvoiceNotFound(invoice_id)
+
+# Good — the chain survives; the traceback shows both
+try:
+    row = fetch(invoice_id)
+except KeyError as e:
+    raise InvoiceNotFound(invoice_id) from e
+```
+
+Two rules with no exceptions:
+
+- **Never bare `except:`.** It catches `KeyboardInterrupt` and `SystemExit` too, so it
+  turns Ctrl-C into a swallowed error. `except Exception` if you truly mean everything.
+- **Never a silent `pass`.** An exception handler that does nothing is a decision to
+  ignore a failure; if that is genuinely right, the handler needs a comment saying why,
+  and usually a log line. Most of the time it is a bug being stored for later.
+
+## Data classes over dicts
+
+A `dict[str, Any]` passed between functions is Go's `map[string]interface{}` — every
+reader has to reconstruct the shape from the code that writes it.
+
+```python
+# Bad: shape known only by reading every producer
+def total(invoice: dict[str, Any]) -> int: ...
+
+# Good: shape declared once, checked everywhere
+@dataclass(frozen=True, slots=True)
+class Invoice:
+    id: InvoiceId
+    lines: tuple[Line, ...]
+    currency: str  # ISO 4217
+
+def total(invoice: Invoice) -> Money: ...
+```
+
+`frozen=True` where the value is conceptually immutable — it makes accidental mutation
+an error rather than a surprise at a distance. Use `pydantic` models at the *boundary*
+(env config, HTTP payloads) where validation is the point, and dataclasses inside,
+where validation has already happened.
+
+## Two Python-specific traps that read as clean code
+
+**Mutable default arguments** are evaluated once, at definition:
+
+```python
+def add_line(line: Line, lines: list[Line] = []) -> list[Line]:  # shared across calls
+```
+
+Use `None` and build inside. Ruff catches this (`B006`); the point of naming it here is
+that the broken version looks tidier than the correct one.
+
+**Truthiness is not presence.** `if not amount:` is true for `0`, `0.0`, `""`, `[]` and
+`None` alike. For anything where zero is a legitimate value — money, counts, offsets —
+write `if amount is None:`. This is the single most common way a Python function
+silently mishandles a valid input.
+
+## Structure
+
+- `src/` layout, `pyproject.toml` only. A flat layout lets tests import the working
+  directory instead of the installed package, so the suite passes on a package that
+  cannot actually be installed.
+- Module names are the unit of cohesion, as Go packages are. `utils.py` is the Python
+  spelling of a god package: it has no reason to change because it has no subject.
+- Prefer functions to classes with one method. A class whose only job is to hold
+  constructor arguments and expose `run()` is a closure with ceremony.
+
+## See also
+
+- `references/clean-code.md` — the language-agnostic practices
+- `references/code-smells.md` — the smell catalogue, all of which apply here
+- `tdd/references/python.md` — the test-side conventions

skills/code-review/SKILL.md

@@ -279,6 +279,8 @@ treats `pass` as success, `fail` as failure, `skip` as neither.
 
 ## References
 
+- `references/python-adaptation.md` — the Python anti-pattern table, and what ruff/mypy
+  should have caught before review
 - `clean-code/references/code-smells.md` — comprehensive smell catalog
 - Load `refactoring` skill when recommending fixes
 - Load `test-design` skill for reviewing test quality

skills/code-review/references/python-adaptation.md

@@ -0,0 +1,60 @@
+# Code Review: Python Anti-Patterns
+
+`SKILL.md` carries the Go anti-pattern table. This is the Python one. The review
+process, severity classification and output format above it are language-neutral and
+apply unchanged.
+
+Canonical stack in `~/dev/.context/AGENT.md`. Two gates decide most of this file:
+`ruff` and `mypy --strict`. **If a finding is something ruff or mypy already catches,
+the review comment is not "fix this line" — it is "why is the gate not running?"**
+
+## The table
+
+| Anti-pattern | What to look for | Why it matters |
+|---|---|---|
+| Bare `except:` | `except:` with no exception class | Swallows `KeyboardInterrupt` and `SystemExit`; Ctrl-C stops working |
+| Silent `pass` | `except X: pass` with no comment | A decision to ignore a failure, recorded nowhere |
+| Lost cause | `raise Y(...)` inside `except X as e` with no `from e` | Traceback loses the original failure — the Python analogue of a naked `fmt.Errorf` |
+| Mutable default | `def f(x, acc=[])` or `={}` | Evaluated once at definition; state leaks between calls |
+| Truthiness for presence | `if not amount:` where `0` is valid | Silently mishandles zero, empty string, empty list |
+| `Any` as an escape | `Any` in a signature that could be `Protocol`/union/`TypeVar` | Removes exactly the checking `--strict` was adopted for |
+| Unexplained ignore | bare `# type: ignore` | No error code, no reason; permanent by default |
+| `assert` in production code | `assert user.is_admin` outside tests | `python -O` strips asserts — the check vanishes in a tuned deployment |
+| Import-time side effects | connections, env reads, or I/O at module scope | Cannot be injected, cannot be tested, ordering-dependent |
+| Sync I/O in `async def` | `requests.get`, `time.sleep`, blocking file reads | Blocks the whole event loop; looks concurrent, is not |
+| Un-awaited coroutine | a call to an `async def` with no `await` | Silently does nothing; "coroutine was never awaited" is a warning, not an error |
+| `float` for money | `float` amounts, `round()` on currency | `0.1 + 0.2 != 0.3`; use `Decimal` or int minor units |
+| Broad `Exception` re-raise | `except Exception` around a whole function body | Turns a specific failure into an unclassifiable one |
+| Mutating a shared default/global | module-level `list`/`dict` mutated by functions | The Python spelling of shared mutable state |
+| `dict[str, Any]` as a domain type | dicts passed between layers | Shape known only by reading every producer; use a dataclass |
+| Star imports | `from x import *` | Breaks `--strict`, hides shadowing, defeats grep |
+| `os.path` string surgery | manual path joining, `+ "/"` | `pathlib` exists and is correct on every platform |
+| `subprocess(..., shell=True)` with interpolation | f-strings into a shell command | Injection; pass a list, no shell |
+
+## What to check that a linter cannot
+
+- **Does the test suite assert the failure mode, or only the happy path?** `pytest.raises`
+  with no `match=` accepts any message, including one from an unrelated bug.
+- **Are fixtures doing real work?** A `conftest.py` fixture with a `session` scope and
+  mutable state couples every test that touches it; failures then depend on ordering.
+- **Is the mock mocking a boundary or a collaborator you own?** The latter tests the mock.
+- **Does the type say what the code means?** `-> dict` and `-> tuple[int, int]` both pass
+  `--strict` and both tell the reader nothing. A named type is a review comment worth
+  making.
+- **Would `--strict` actually run on this file?** Check for a per-module override in
+  `pyproject.toml` silently exempting it. An exemption nobody revisits is a hole with a
+  changelog entry.
+
+## Severity in this context
+
+- **Blocking:** anything in the table above under security or correctness — `shell=True`
+  interpolation, `assert` as an authorization check, `float` money, sync I/O in async.
+- **Should fix:** typing escapes (`Any`, unexplained ignores), mutable defaults,
+  truthiness-for-presence.
+- **Consider:** structural comments — dataclass instead of dict, narrower Protocol.
+
+## See also
+
+- `clean-code/references/python-adaptation.md` — the style-level conventions
+- `solid/references/python-adaptation.md` — Protocol over ABC, DIP in Python
+- `tdd/references/python.md` — the test-side conventions this review checks against

skills/feature-spec/SKILL.md

@@ -32,6 +32,90 @@ A feature spec is the implementation-level contract for one feature or component
 2. **An "Out of scope" section is mandatory.** If you do not draw the boundary, the implementer (you, future-you, or another agent) will guess wrong.
 3. **Every technical decision in "Technical approach" must have a rationale.** A decision is any choice where a reasonable alternative existed and was not taken. "Use Postgres" is not a decision; "use Postgres because the rest of the stack uses it and we need transactions across user + invoice" is.
 
+## EARS-lite acceptance criteria
+
+Measurable criteria answer "is it done?". They do not always answer "what should it do
+when X happens?" — and behavioural requirements written as prose are where ambiguity
+survives review. For any criterion that is conditional or event-driven, use EARS-lite
+instead of prose:
+
+```
+WHEN <trigger> THE SYSTEM SHALL <observable response>
+WHILE <state> THE SYSTEM SHALL <observable response>
+IF <unwanted condition> THEN THE SYSTEM SHALL <observable response>
+```
+
+There is a fourth, unconditional form. Use it for invariants — the properties that must
+hold with no trigger at all, which are usually the ones that matter most:
+
+```
+THE SYSTEM SHALL <observable response>
+```
+
+Worked, deliberately from a domain unlike whatever you are specifying:
+
+```
+THE SYSTEM SHALL reject a firmware image whose signature does not verify
+WHEN a sensor reports a temperature above the shutdown limit
+  THE SYSTEM SHALL open the contactor within 200ms
+WHILE the contactor is open
+  THE SYSTEM SHALL refuse every start command
+IF a sensor reading is missing or stale by more than one interval
+  THEN THE SYSTEM SHALL treat it as above the limit
+```
+
+The example is off-domain on purpose. An on-domain example gets copied: a spec written
+against an invoice-flavoured example inherited a requirement about extraction confidence
+that its feature request never mentioned, and the author only noticed on review. Read
+the shapes, not the content.
+
+Each conditional line names a trigger and one observable response, which usually maps
+onto a single test. The `WHILE` and unconditional forms are universally quantified —
+"every start command", "a firmware image" — so they map onto a property or a set of
+cases, not one assertion. That is still worth writing: it closes the requirements half
+of the audit trail, which is otherwise issue-body prose.
+
+**This is an option, not a replacement.** Threshold criteria ("p99 < 200ms under 100
+RPS") stay as they are — EARS phrasing adds nothing to a number. Use it for conditional
+behaviour, error handling, and state-dependent rules.
+
+## Context snapshot
+
+The executor of this spec will not see the conversation that produced it, and often
+cannot see the architecture document either — a different agent, a fresh session, a
+different machine. A spec that says "see the architecture doc" hands them a lookup they
+may not be able to perform.
+
+So inline the specific facts this spec depends on, not the whole document:
+
+```markdown
+## Context snapshot
+Taken from <source> @ <commit-or-date>. Re-check before implementing if stale.
+
+- The mailbox poller writes rows to `invoices` with `state = 'received'`.
+- The payment-file writer reads `invoices` and emits one file per batch.
+- Money is int64 minor units plus an ISO-4217 code; float is banned repo-wide.
+```
+
+Three rules keep this from becoming a second source of truth, which is the real
+objection to inlining and a good one:
+
+1. **Snapshot what the implementer cannot look up and cannot proceed without.** That is
+   wider than "facts this spec's decisions rest on" — a table name may underpin no
+   decision here and still be the thing that blocks writing the migration. It is still
+   narrower than the whole document: if a fact changes nothing and blocks nothing, leave
+   it out, and say what you left out so the omission reads as deliberate.
+2. **Always cite source and version.** A snapshot without provenance cannot be
+   revalidated, and an unrevalidatable copy is exactly the drift everyone fears.
+3. **If you could not read the source either, say so in those words.** Writing a spec
+   against a document you cannot open is common and is not a reason to skip the section
+   — it is a reason to mark the whole block `UNVERIFIED — reconstructed, not read`, and
+   to make confirming it the implementer's first task, before the first failing test.
+   An unmarked guess is the only genuinely dangerous version.
+4. **The snapshot is evidence, not authority.** Open the section with one line to that
+   effect — "where this disagrees with the source, the source wins and this spec is
+   stale" — rather than annotating each fact.
+
 ## Spec Template
 
 ```markdown
@@ -42,12 +126,21 @@ A feature spec is the implementation-level contract for one feature or component
 What problem does this feature solve? For whom? Why now?
 (2-4 sentences. If you cannot answer "why now," ask before writing the rest.)
 
+## Context snapshot
+[Facts the implementer cannot look up, with source and version. See "Context snapshot" above.]
+
 ## Success Criteria
 
 - [ ] Criterion 1 — measurable and verifiable
 - [ ] Criterion 2 — measurable and verifiable
 - [ ] Criterion 3 — measurable and verifiable
 
+### Behavioural criteria (EARS-lite)
+
+[Conditional and event-driven behaviour, one trigger and one observable response per
+line. Not checkboxes — these are properties, and several need more than one test each.
+Omit the subsection entirely if the feature has no conditional behaviour.]
+
 ## Constraints
 
 Non-negotiable requirements the solution must satisfy.

skills/solid/SKILL.md

@@ -258,5 +258,6 @@ Domain types know nothing about HTTP, SQL, or external APIs.
 
 - `references/solid-principles.md` — canonical SOLID reference with TypeScript examples
 - `references/go-adaptation.md` — this workspace's Go-specific rewrite of each principle
+- `references/python-adaptation.md` — the Python rewrite: Protocol over ABC, and what does not carry over from Go
 - Load `clean-code` skill for naming and structure
 - Load `code-review` skill for detecting violations during review

skills/solid/references/python-adaptation.md

@@ -0,0 +1,104 @@
+# SOLID Principles: Python Adaptation
+
+`references/go-adaptation.md` rewrites each principle for Go. This file does the same
+for Python, and marks the places where the Go rewrite's advice does *not* carry over.
+
+The canonical Python stack lives in `~/dev/.context/AGENT.md`; it is not restated here.
+
+## The one idea that changes everything: `Protocol`
+
+Go's interfaces are structural — a type satisfies one by having the methods, with no
+declaration. Python has the same thing since 3.8, and it is the right default:
+
+```python
+from typing import Protocol
+
+class InvoiceStore(Protocol):
+    def get(self, invoice_id: InvoiceId) -> Invoice: ...
+    def save(self, invoice: Invoice) -> None: ...
+```
+
+- **Define the Protocol where it is *consumed*, not where it is implemented.** This is
+  Go's "accept interfaces, return structs" and it is what makes DIP real: the high-level
+  module owns the abstraction, and the adapter depends on it rather than the reverse.
+- **Prefer `Protocol` to `ABC`.** An ABC forces implementers to inherit, which couples
+  them to your package and makes a third-party class impossible to adapt without a
+  wrapper. Use an ABC only when you genuinely need shared implementation, not just a
+  contract.
+- Add `@runtime_checkable` only if you actually call `isinstance` — and if you are
+  calling `isinstance` against a Protocol, check whether the real problem is a missing
+  polymorphic method (an LSP smell).
+
+## S — Single Responsibility
+
+Same as Go: the unit is the module, not just the class. `utils.py` is the Python god
+package — it cannot have one reason to change because it has no subject.
+
+Python-specific tell: a class whose `__init__` stores arguments and whose only other
+method is `run()` or `execute()`. That is a function with ceremony. Write the function.
+
+## O — Open/Closed
+
+Extension in Python usually means **passing behaviour in**, not subclassing:
+
+```python
+# Closed for modification: adding a rule does not touch this function
+def apply_rules(invoice: Invoice, rules: Sequence[Rule]) -> Invoice: ...
+```
+
+`functools.singledispatch` is the idiomatic open extension point when dispatch is on
+type and the set of types grows outside your module. Beware the alternative that looks
+Pythonic and is not: monkey-patching is modification pretending to be extension, and it
+is invisible at the call site.
+
+## L — Liskov
+
+The Python-specific violation is **signature widening/narrowing that the type checker
+would catch if you let it**. Under `mypy --strict`, an override that narrows a parameter
+type or widens a return type is an error — which means most LSP violations in Python are
+type errors you chose not to see. This is the strongest argument for `--strict` in a
+design document rather than a style one.
+
+Raising a *new* exception type in an override is the violation `mypy` will not catch:
+callers wrote `except StoreError`, and your subclass raises `TimeoutError`. Exceptions
+are part of the contract; Python just will not check them for you.
+
+## I — Interface Segregation
+
+Protocols make this cheap: define the narrow one you need at the call site.
+
+```python
+class InvoiceReader(Protocol):
+    def get(self, invoice_id: InvoiceId) -> Invoice: ...
+```
+
+A function that only reads should accept `InvoiceReader`, not the full `InvoiceStore`.
+The test double then implements one method instead of eight, which is the practical
+payoff and the reason this principle survives contact with real code.
+
+## D — Dependency Inversion
+
+Constructor injection, exactly as in Go. Two Python-specific hazards:
+
+- **Import-time side effects are hidden dependencies.** A module that opens a database
+  connection or reads an env var at import has a dependency nothing can inject and no
+  test can replace. Configuration belongs in `pydantic-settings` objects passed in.
+- **Default arguments are compile-time bindings.** `def send(client: Client = Client())`
+  constructs the default once, at definition, and welds it to every caller. Default to
+  `None` and construct inside, or require it.
+
+## What does not carry over from the Go rewrite
+
+- **"Return structs, accept interfaces"** — the returning half is about Go's zero values
+  and nil interfaces. In Python, returning a Protocol type is fine and often better.
+- **Small interfaces because of embedding** — Python has no embedding; composition is
+  explicit delegation, which is more verbose but reads honestly.
+- **Package-level responsibility as the unit of deployment** — Python packaging is much
+  looser. The module boundary is still the right unit for *reasoning*, but do not expect
+  it to be enforced.
+
+## See also
+
+- `references/solid-principles.md` — the canonical, language-neutral reference
+- `references/go-adaptation.md` — the Go rewrite; contrast is instructive
+- `clean-code/references/python-adaptation.md` — style-level Python conventions

skills/spec-driven-dev/SKILL.md

@@ -200,6 +200,56 @@ Dev:     [full command]
 [Anything unresolved that needs input before implementation begins]
 ```
 
+## EARS-lite acceptance criteria
+
+Measurable criteria answer "is it done?". They do not always answer "what should it do
+when X happens?" — and behavioural requirements written as prose are where ambiguity
+survives review. For any criterion that is conditional or event-driven, use EARS-lite
+instead of prose:
+
+```
+WHEN <trigger> THE SYSTEM SHALL <observable response>
+WHILE <state> THE SYSTEM SHALL <observable response>
+IF <unwanted condition> THEN THE SYSTEM SHALL <observable response>
+```
+
+There is a fourth, unconditional form. Use it for invariants — the properties that must
+hold with no trigger at all, which are usually the ones that matter most:
+
+```
+THE SYSTEM SHALL <observable response>
+```
+
+Worked, deliberately from a domain unlike whatever you are specifying:
+
+```
+THE SYSTEM SHALL reject a firmware image whose signature does not verify
+WHEN a sensor reports a temperature above the shutdown limit
+  THE SYSTEM SHALL open the contactor within 200ms
+WHILE the contactor is open
+  THE SYSTEM SHALL refuse every start command
+IF a sensor reading is missing or stale by more than one interval
+  THEN THE SYSTEM SHALL treat it as above the limit
+```
+
+The example is off-domain on purpose. An on-domain example gets copied: a spec written
+against an invoice-flavoured example inherited a requirement about extraction confidence
+that its feature request never mentioned, and the author only noticed on review. Read
+the shapes, not the content.
+
+Each conditional line names a trigger and one observable response, which usually maps
+onto a single test. The `WHILE` and unconditional forms are universally quantified —
+"every start command", "a firmware image" — so they map onto a property or a set of
+cases, not one assertion. That is still worth writing: it closes the requirements half
+of the audit trail, which is otherwise issue-body prose.
+
+**This is an option, not a replacement.** Threshold criteria ("p99 < 200ms under 100
+RPS") stay as they are — EARS phrasing adds nothing to a number. Use it for conditional
+behaviour, error handling, and state-dependent rules.
+
+For the executor-facing handoff, `feature-spec` also carries a **Context snapshot**
+section — inline the architecture facts the implementer cannot look up.
+
 ## Reframing Vague Requirements
 
 When you receive a vague requirement, translate it into specific success criteria before writing any spec content:

skills/superpowers-brainstorming/spec-document-reviewer-prompt.md

@@ -7,7 +7,7 @@ Use this template when dispatching a spec document reviewer subagent.
 **Dispatch after:** Spec document is written to docs/superpowers/specs/
 
 ```
-Task tool (general-purpose):
+Agent tool (`subagent_type: "general-purpose"`):
   description: "Review spec document"
   prompt: |
     You are a spec document reviewer. Verify this spec is complete and ready for planning.

skills/superpowers-dispatching-parallel-agents/SKILL.md

@@ -68,13 +68,30 @@ Each agent gets:
 
 ### 3. Dispatch in Parallel
 
-```typescript
-// In Claude Code / AI environment
-Task("Fix agent-tool-abort.test.ts failures")
-Task("Fix batch-completion-behavior.test.ts failures")
-Task("Fix tool-approval-race-conditions.test.ts failures")
-// All three run concurrently
+Issue every dispatch in **one** message — several `Agent` tool uses in a single
+assistant turn run concurrently; one per turn runs them in series.
+
 ```
+Agent(description: "fix abort tests",   subagent_type: "general-purpose", prompt: ...)
+Agent(description: "fix batch tests",   subagent_type: "general-purpose", prompt: ...)
+Agent(description: "fix approval tests", subagent_type: "general-purpose", prompt: ...)
+```
+
+Options that matter for this pattern:
+
+- `run_in_background: true` (the default) returns immediately and notifies on
+  completion. Set it to `false` only when your very next action depends on the result.
+- `isolation: "worktree"` gives an agent its own git worktree. Use it whenever two
+  agents might touch the same files — parallel writers to one tree is the failure this
+  skill's independence rule exists to avoid, and a worktree makes it structural rather
+  than a matter of discipline.
+- `model` overrides the model per agent; cheap mechanical fan-out does not need the
+  same model as the reasoning that planned it.
+
+For a fan-out with real structure — phases, a verify pass per finding, fan-in — the
+`Workflow` tool expresses it directly with `agent()`, `parallel()` and `pipeline()`.
+It spawns many agents and costs accordingly, so it runs **only on explicit opt-in from
+the operator**; do not reach for it just because a task looks parallel.
 
 ### 4. Review and Integrate
 

skills/superpowers-executing-plans/SKILL.md

@@ -14,14 +14,16 @@ Load plan, review critically, execute all tasks, report when complete.
 
 **Announce at start:** "I'm using the executing-plans skill to implement this plan."
 
-**Note:** Tell your human partner that Superpowers works much better with access to subagents. The quality of its work will be significantly higher if run on a platform with subagent support (such as Claude Code or Codex). If subagents are available, use superpowers:subagent-driven-development instead of this skill.
+**Note:** This skill is the fallback for harnesses with no subagents. Claude Code has
+them — the `Agent` tool — so on this fleet prefer `superpowers-subagent-driven-development`
+and use this skill only where `Agent` is genuinely unavailable (Crush, Pi, OpenCode).
 
 ## The Process
 
 ### Step 1: Load and Review Plan
 1. Read plan file
 2. Review critically - identify any questions or concerns about the plan
-3. If concerns: Raise them with your human partner before starting
+3. If concerns: Raise them with the operator before starting
 4. If no concerns: Create TodoWrite and proceed
 
 ### Step 2: Execute Tasks

skills/superpowers-receiving-code-review/SKILL.md

@@ -54,7 +54,7 @@ WHY: Items may be related. Partial understanding = wrong implementation.
 
 **Example:**
 ```
-your human partner: "Fix 1-6"
+the operator: "Fix 1-6"
 You understand 1,2,3,6. Unclear on 4,5.
 
 ❌ WRONG: Implement 1,2,3,6 now, ask about 4,5 later
@@ -63,7 +63,7 @@ You understand 1,2,3,6. Unclear on 4,5.
 
 ## Source-Specific Handling
 
-### From your human partner
+### From the operator
 - **Trusted** - implement after understanding
 - **Still ask** if scope unclear
 - **No performative agreement**
@@ -84,11 +84,11 @@ IF suggestion seems wrong:
 IF can't easily verify:
   Say so: "I can't verify this without [X]. Should I [investigate/ask/proceed]?"
 
-IF conflicts with your human partner's prior decisions:
-  Stop and discuss with your human partner first
+IF conflicts with the operator's prior decisions:
+  Stop and discuss with the operator first
 ```
 
-**your human partner's rule:** "External feedback - be skeptical, but check carefully"
+**the operator's rule:** "External feedback - be skeptical, but check carefully"
 
 ## YAGNI Check for "Professional" Features
 
@@ -100,7 +100,7 @@ IF reviewer suggests "implementing properly":
   IF used: Then implement properly
 ```
 
-**your human partner's rule:** "You and reviewer both report to me. If we don't need this feature, don't add it."
+**the operator's rule:** "You and reviewer both report to me. If we don't need this feature, don't add it."
 
 ## Implementation Order
 
@@ -123,13 +123,13 @@ Push back when:
 - Violates YAGNI (unused feature)
 - Technically incorrect for this stack
 - Legacy/compatibility reasons exist
-- Conflicts with your human partner's architectural decisions
+- Conflicts with the operator's architectural decisions
 
 **How to push back:**
 - Use technical reasoning, not defensiveness
 - Ask specific questions
 - Reference working tests/code
-- Involve your human partner if architectural
+- Involve the operator if architectural
 
 **Signal if uncomfortable pushing back out loud:** "Strange things are afoot at the Circle K"
 
@@ -200,7 +200,7 @@ Reviewer: "Implement proper metrics tracking with database, date filters, CSV ex
 
 **Unclear Item (Good):**
 ```
-your human partner: "Fix items 1-6"
+the operator: "Fix items 1-6"
 You understand 1,2,3,6. Unclear on 4,5.
 ✅ "Understand 1,2,3,6. Need clarification on 4 and 5 before implementing."
 ```

skills/superpowers-requesting-code-review/SKILL.md

@@ -36,7 +36,9 @@ HEAD_SHA=$(git rev-parse HEAD)
 
 **2. Dispatch code reviewer subagent:**
 
-Use Task tool with `general-purpose` type, fill template at `code-reviewer.md`
+Use the `Agent` tool with `subagent_type: "general-purpose"`, filling the template at
+`code-reviewer.md`. A reviewer needs no write access and benefits from none — if the
+harness offers a read-only agent type, prefer it.
 
 **Placeholders:**
 - `{DESCRIPTION}` - Brief summary of what you built

skills/superpowers-requesting-code-review/code-reviewer.md

@@ -5,7 +5,7 @@ Use this template when dispatching a code reviewer subagent.
 **Purpose:** Review completed work against requirements and code quality standards before it cascades into more work.
 
 ```
-Task tool (general-purpose):
+Agent tool (`subagent_type: "general-purpose"`):
   description: "Review code changes"
   prompt: |
     You are a Senior Code Reviewer with expertise in software architecture,

skills/superpowers-subagent-driven-development/SKILL.md

@@ -14,7 +14,7 @@ Execute plan by dispatching fresh subagent per task, with two-stage review after
 
 **Core principle:** Fresh subagent per task + two-stage review (spec then quality) = high quality, fast iteration
 
-**Continuous execution:** Do not pause to check in with your human partner between tasks. Execute all tasks from the plan without stopping. The only reasons to stop are: BLOCKED status you cannot resolve, ambiguity that genuinely prevents progress, or all tasks complete. "Should I continue?" prompts and progress summaries waste their time — they asked you to execute the plan, so execute it.
+**Continuous execution:** Do not pause to check in with the operator between tasks. Execute all tasks from the plan without stopping. The only reasons to stop are: BLOCKED status you cannot resolve, ambiguity that genuinely prevents progress, or all tasks complete. "Should I continue?" prompts and progress summaries waste their time — they asked you to execute the plan, so execute it.
 
 ## When to Use
 

skills/superpowers-subagent-driven-development/code-quality-reviewer-prompt.md

@@ -7,7 +7,7 @@ Use this template when dispatching a code quality reviewer subagent.
 **Only dispatch after spec compliance review passes.**
 
 ```
-Task tool (general-purpose):
+Agent tool (`subagent_type: "general-purpose"`):
   Use template at requesting-code-review/code-reviewer.md
 
   DESCRIPTION: [task summary, from implementer's report]

skills/superpowers-subagent-driven-development/implementer-prompt.md

@@ -3,7 +3,7 @@
 Use this template when dispatching an implementer subagent.
 
 ```
-Task tool (general-purpose):
+Agent tool (`subagent_type: "general-purpose"`):
   description: "Implement Task N: [task name]"
   prompt: |
     You are implementing Task N: [task name]

skills/superpowers-subagent-driven-development/spec-reviewer-prompt.md

@@ -5,7 +5,7 @@ Use this template when dispatching a spec compliance reviewer subagent.
 **Purpose:** Verify implementer built what was requested (nothing more, nothing less)
 
 ```
-Task tool (general-purpose):
+Agent tool (`subagent_type: "general-purpose"`):
   description: "Review spec compliance for Task N"
   prompt: |
     You are reviewing whether an implementation matches its specification.

skills/superpowers-using-superpowers/references/gemini-tools.md

@@ -24,11 +24,11 @@ When a skill says to dispatch a named agent type, use `@generalist` with the ful
 
 | Skill instruction | Gemini CLI equivalent |
 |-------------------|----------------------|
-| `Task tool (superpowers:implementer)` | `@generalist` with the filled `implementer-prompt.md` template |
-| `Task tool (superpowers:spec-reviewer)` | `@generalist` with the filled `spec-reviewer-prompt.md` template |
-| `Task tool (superpowers:code-reviewer)` | `@code-reviewer` (bundled agent) or `@generalist` with the filled review prompt |
-| `Task tool (superpowers:code-quality-reviewer)` | `@generalist` with the filled `code-quality-reviewer-prompt.md` template |
-| `Task tool (general-purpose)` with inline prompt | `@generalist` with your inline prompt |
+| `Agent tool (superpowers:implementer)` | `@generalist` with the filled `implementer-prompt.md` template |
+| `Agent tool (superpowers:spec-reviewer)` | `@generalist` with the filled `spec-reviewer-prompt.md` template |
+| `Agent tool (superpowers:code-reviewer)` | `@code-reviewer` (bundled agent) or `@generalist` with the filled review prompt |
+| `Agent tool (superpowers:code-quality-reviewer)` | `@generalist` with the filled `code-quality-reviewer-prompt.md` template |
+| `Agent tool (general-purpose)` with inline prompt | `@generalist` with your inline prompt |
 
 ### Prompt filling
 

skills/superpowers-verification-before-completion/SKILL.md

@@ -111,7 +111,7 @@ Skip any step = lying, not verifying
 ## Why This Matters
 
 From 24 failure memories:
-- your human partner said "I don't believe you" - trust broken
+- the operator said "I don't believe you" - trust broken
 - Undefined functions shipped - would crash
 - Missing requirements shipped - incomplete features
 - Time wasted on false completion → redirect → rework

skills/superpowers-writing-plans/plan-document-reviewer-prompt.md

@@ -7,7 +7,7 @@ Use this template when dispatching a plan document reviewer subagent.
 **Dispatch after:** The complete plan is written.
 
 ```
-Task tool (general-purpose):
+Agent tool (`subagent_type: "general-purpose"`):
   description: "Review plan document"
   prompt: |
     You are a plan document reviewer. Verify this plan is complete and ready for implementation.

skills/superpowers-writing-skills/SKILL.md

@@ -246,7 +246,7 @@ Always use subagents (50-100x context savings). REQUIRED: Use [other-skill-name]
 **Compress examples:**
 ```markdown
 # ❌ BAD: Verbose example (42 words)
-your human partner: "How did we handle authentication errors in React Router before?"
+the operator: "How did we handle authentication errors in React Router before?"
 You: I'll search past conversations for React Router authentication patterns.
 [Dispatch subagent with search query: "React Router authentication error handling 401"]
 
@@ -318,7 +318,7 @@ digraph when_flowchart {
 
 See @graphviz-conventions.dot for graphviz style rules.
 
-**Visualizing for your human partner:** Use `render-graphs.js` in this directory to render a skill's flowcharts to SVG:
+**Visualizing for the operator:** Use `render-graphs.js` in this directory to render a skill's flowcharts to SVG:
 ```bash
 ./render-graphs.js ../some-skill           # Each diagram separately
 ./render-graphs.js ../some-skill --combine # All diagrams in one SVG

skills/tdd/SKILL.md

@@ -100,13 +100,21 @@ go test -run TestRetryOperation_RetriesThreeTimes ./...
 ```
 
 Confirm:
-- Test fails (not compilation errors)
-- Failure message is expected
-- Fails because feature is missing (not typos)
+- Test fails, and fails because the feature is missing
+- The failure message is the one you expected
+- It is not failing on a typo in the test itself
 
 **Test passes?** You're testing existing behavior. Fix test.
 
-**Compilation errors?** Fix errors, re-run until it fails correctly.
+**Failing because the thing does not exist yet?** That is a legitimate red — a Go
+compile error for an undefined function, a Python `ImportError` for a module you have
+not written, a TypeScript "cannot find module". Read the message, confirm it names the
+unit you are about to build, and proceed to GREEN. **Do not write a stub to make the
+runner happier.** A stub is production code written before a failing test, which is the
+Iron Law with extra steps.
+
+**Failing on a typo or a broken import elsewhere?** Different thing. Fix it and re-run
+until the failure is the one above.
 
 ### GREEN - Minimal Code
 
@@ -166,6 +174,23 @@ Keep tests green. Don't add behavior.
 
 Next failing test for next behavior.
 
+## Other languages
+
+The discipline above is language-neutral; the examples below it are Go, because Go is
+this fleet's default stack and one good example beats five mediocre ones.
+
+For anything else, the per-language conventions live in reference files — load the one
+you need rather than translating Go idioms by eye. Translation is where the mistakes
+happen: the Go table-driven exemplar below branches on a `wantErr` column inside the
+loop, which is idiomatic Go and an anti-pattern in pytest, where it produces a
+conditional assertion and folds two behaviours into one test.
+
+- `references/python.md` — pytest, `@pytest.mark.parametrize`, `mypy --strict` in the
+  RED gate, `pytest.raises(..., match=)`, fixtures vs helpers
+- `references/typescript.md` — vitest/jest, `it.each`, `expect(...).rejects`
+- `references/rust.md` — `#[cfg(test)]` modules, table-driven via arrays, `#[should_panic]`
+- `references/java.md` — JUnit 5, `@ParameterizedTest`, `assertThrows`
+
 ## Go-Specific TDD Notes
 
 ### Table-Driven Tests (Preferred Pattern)
@@ -329,8 +354,14 @@ Before marking work complete:
 - [ ] Watched each test fail before implementing
 - [ ] Each test failed for expected reason (feature missing, not typo)
 - [ ] Wrote minimal code to pass each test
-- [ ] All tests pass: `go test ./...`
-- [ ] Race detector clean: `go test -race ./...`
+- [ ] All tests pass
+- [ ] The language's static gate is clean — `go vet`, `mypy --strict`, `tsc --noEmit`,
+      `cargo clippy`. A red type-check is a red build; it does not wait for GREEN.
+- [ ] The language's concurrency gate is clean **where one exists and applies** —
+      `go test -race`, `cargo test` under Miri for unsafe code. There is no equivalent
+      for a pure Python function, and a checklist box that can never be ticked teaches
+      people to skip checklists. Tick it or strike it deliberately; do not leave it
+      hanging.
 - [ ] Tests use real code (mocks only if crossing a system boundary)
 - [ ] Edge cases and errors covered
 

skills/tdd/references/java.md

@@ -0,0 +1,78 @@
+# TDD in Java
+
+The Iron Law and Red-Green-Refactor in `SKILL.md` apply unchanged. This file replaces
+the Go-Specific TDD Notes for Java. JUnit 5 (Jupiter) throughout.
+
+## The first red is a compile error, and that is correct
+
+`cannot find symbol: method splitVat` is a legitimate red. Do not stub the method with
+`throw new UnsupportedOperationException()` to make the module compile — that is
+production code before a failing test.
+
+## Table-driven: `@ParameterizedTest`
+
+```java
+@ParameterizedTest(name = "{0}")
+@MethodSource("vatCases")
+void roundsHalfToEven(String name, long amountMinor, BigDecimal rate, long net, long vat) {
+    assertEquals(new Split(net, vat), VatSplitter.split(amountMinor, rate));
+}
+
+static Stream<Arguments> vatCases() {
+    return Stream.of(
+        Arguments.of("tie rounds down to even", 14L,    new BigDecimal("0.12"), 12L,    2L),
+        Arguments.of("tie rounds up to even",   42L,    new BigDecimal("0.12"), 38L,    4L),
+        Arguments.of("exact division",          12500L, new BigDecimal("0.25"), 10000L, 2500L)
+    );
+}
+```
+
+`name = "{0}"` puts the case label in the report — the `t.Run` analogue. `@CsvSource` is
+terser for primitives; `@MethodSource` is the one to use as soon as a case carries a
+`BigDecimal` or a domain object.
+
+## Error cases get their own test
+
+```java
+@Test
+void rejectsNegativeAmount() {
+    var e = assertThrows(IllegalArgumentException.class,
+                         () -> VatSplitter.split(-1, new BigDecimal("0.25")));
+    assertTrue(e.getMessage().contains("non-negative"));
+}
+```
+
+Assert on the message, not only the type — `IllegalArgumentException` is thrown by half
+the JDK, and a test that accepts any of them will keep passing for the wrong reason.
+
+## Money is `BigDecimal` or `long` minor units, never `double`
+
+`0.1 + 0.2 != 0.3` is not a rounding curiosity in a payments system, it is a defect.
+Where a rounding mode matters, state it: `setScale(0, RoundingMode.HALF_EVEN)`. Banker's
+rounding is the default expectation in Swedish accounting and is *not* Java's default.
+
+## Assertions
+
+Prefer AssertJ (`assertThat(x).isEqualTo(y)`) where the project already has it: the
+failure messages name the actual value. Where it does not, plain JUnit assertions are
+fine — do not add a dependency for aesthetics.
+
+`assertAll` is the closest analogue to Go's soft `assert`: it reports every failure in
+the group instead of stopping at the first.
+
+## Mocks
+
+Mockito is standard, and easy to overuse. Per `SKILL.md`, mock only across a system
+boundary. A mocked class you own tests the mock; a `@SpringBootTest` that mocks the
+repository tests neither the wiring nor the query.
+
+## Gates
+
+```bash
+./gradlew test            # the failing test
+./gradlew check           # static gate: compiler warnings, spotless, errorprone
+```
+
+Java has no `-race`. For concurrent code the honest substitutes are a stress test with
+`CountDownLatch` to force the interleaving, and jcstress for lock-free work. A pure
+function should strike that checklist box deliberately.

skills/tdd/references/python.md

@@ -0,0 +1,109 @@
+# TDD in Python
+
+The Iron Law, Red-Green-Refactor and the rationalization table in `SKILL.md` apply
+unchanged. This file replaces the Go-Specific TDD Notes for Python work.
+
+Canonical stack (`~/dev/.context/AGENT.md`): pytest + pytest-cov, `mypy --strict`, ruff,
+uv, src-layout. Not restated here — that table has one home.
+
+## The first red is an ImportError, and that is correct
+
+For a function that does not exist yet, the first run fails at collection:
+
+```
+E   ModuleNotFoundError: No module named 'invoicing.vat'
+```
+
+That is a legitimate red. Read it, confirm it names the module you are about to write,
+and go to GREEN. **Do not create a stub raising `NotImplementedError` to make pytest
+collect.** A stub is production code written before a failing test.
+
+## Table-driven: `parametrize`, one behaviour per function
+
+```python
+@pytest.mark.parametrize(
+    ("amount_minor", "rate", "expected"),
+    [
+        pytest.param(14, Decimal("0.12"), (12, 2), id="tie-rounds-down-to-even"),
+        pytest.param(42, Decimal("0.12"), (38, 4), id="tie-rounds-up-to-even"),
+        pytest.param(12500, Decimal("0.25"), (10000, 2500), id="exact-division"),
+        pytest.param(0, Decimal("0.25"), (0, 0), id="zero-is-not-an-error"),
+    ],
+)
+def test_split_vat_rounds_half_to_even(
+    amount_minor: int, rate: Decimal, expected: tuple[int, int]
+) -> None:
+    assert split_vat(amount_minor, rate) == expected
+```
+
+`id=` is the analogue of Go's `t.Run` name: it is what appears in the failure output and
+what you pass to `pytest -k`.
+
+**Do not port Go's `wantErr` column.** The Go exemplar branches inside the loop —
+`if tt.wantErr { assert.Error } else { assert.NoError }`. Translated literally that
+gives a conditional assertion and folds two behaviours into one test, which `SKILL.md`'s
+own quality table forbids ("One thing. 'and' in name? Split it."). Error cases get
+their own function:
+
+```python
+def test_split_vat_rejects_negative_amount() -> None:
+    with pytest.raises(ValueError, match="amount_minor must be non-negative"):
+        split_vat(-1, Decimal("0.25"))
+```
+
+`match=` pins the message, not just the type. Go's `assert.Error` does not, and the
+stricter version is available here for free — use it.
+
+## `mypy --strict` is part of RED, not a chore after GREEN
+
+A red type-check is a red build.
+
+```bash
+uv run pytest tests/test_vat.py -x -q       # the failing test
+uv run mypy --strict src tests              # same gate, same phase
+```
+
+Under `--strict` every test function needs `-> None`, or it is an untyped def and the
+type-checker rejects the file — including the file that holds your failing test.
+
+## Layout and imports
+
+- `src/` layout, tests in a sibling `tests/`. This is the *opposite* of Go's
+  same-directory convention, and it buys black-box testing structurally: `from
+  invoicing.vat import split_vat` can only resolve against the installed package, so
+  the preference Go has to state explicitly is enforced here by the import system.
+- No `__init__.py` in `tests/` unless you need shared test packages; pytest's rootdir
+  handling copes, and an accidental package shadows names.
+- `conftest.py` holds fixtures shared across a directory. A fixture in a single test
+  file that only one test uses should be a plain function call instead — fixtures are
+  indirection, and indirection is only worth it at reuse.
+
+## No `require` vs `assert`
+
+Every pytest `assert` is fatal to its test; there is no continue-on-failure form. Where
+Go would use `assert` to collect several soft failures, either split the test or use
+`pytest.approx`/a single structural comparison:
+
+```python
+assert result == Invoice(id=InvoiceId("42"), net=10000, vat=2500)   # one assertion, whole shape
+```
+
+Comparing whole values beats three field assertions: the failure output shows the entire
+diff rather than the first field that differed.
+
+## Fixtures vs helpers
+
+- **Helper function** — when the setup is cheap and local. It reads top-to-bottom.
+- **Fixture** — when the setup is shared, or needs teardown, or needs a scope
+  (`session`, `module`) because it is expensive.
+- Set `__tracebackhide__ = True` in an assertion helper so failures point at the caller,
+  the way `t.Helper()` does in Go.
+
+## Coverage is not the concurrency gate
+
+`SKILL.md`'s checklist asks for the language's concurrency gate. Python has no `-race`
+equivalent, and pretending `pytest --cov` fills that slot is dishonest — coverage says
+which lines ran, not whether two threads can interleave badly. For a pure function,
+strike the box deliberately. For genuinely concurrent code (`asyncio`, threads), the
+substitute is a test that runs the interleaving you fear, plus `pytest-timeout` so a
+deadlock fails rather than hangs.

skills/tdd/references/rust.md

@@ -0,0 +1,86 @@
+# TDD in Rust
+
+The Iron Law and Red-Green-Refactor in `SKILL.md` apply unchanged. This file replaces
+the Go-Specific TDD Notes for Rust.
+
+## The first red is a compile error, and that is correct
+
+```
+error[E0425]: cannot find function `split_vat` in this scope
+```
+
+Legitimate — the compiler is the test runner's first phase. Read it, confirm it names
+the item you are about to write, and go to GREEN. Do not write a `todo!()` stub first;
+that is production code before a failing test. (`todo!()` is fine *during* GREEN as a
+branch you have not reached yet.)
+
+## Where tests live
+
+- **Unit tests** in the same file, in `mod tests` behind `#[cfg(test)]`. They can reach
+  private items — the white-box option Go spells `package foo`.
+- **Integration tests** in `tests/`, which link the crate as an external consumer and see
+  only the public API. This is the black-box default `SKILL.md` prefers; use it unless
+  the behaviour under test is genuinely private.
+
+```rust
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn tie_rounds_down_to_even() {
+        assert_eq!(split_vat(14, dec!(0.12)).unwrap(), (12, 2));
+    }
+}
+```
+
+## Table-driven: an array of cases
+
+```rust
+#[test]
+fn rounds_half_to_even() {
+    let cases = [
+        ("tie rounds down", 14u64, dec!(0.12), (12, 2)),
+        ("tie rounds up", 42, dec!(0.12), (38, 4)),
+        ("exact division", 12500, dec!(0.25), (10000, 2500)),
+    ];
+    for (name, amount, rate, want) in cases {
+        assert_eq!(split_vat(amount, rate).unwrap(), want, "case: {name}");
+    }
+}
+```
+
+The `"case: {name}"` message is the `t.Run` analogue — without it a failure names a line
+number and leaves you counting rows. If you want each case to be its own reported test,
+use `rstest`'s `#[case]`; that is a dependency, so justify it before adding it.
+
+## Error cases
+
+`Result` makes the Go `wantErr` column unnecessary — assert on the variant:
+
+```rust
+#[test]
+fn rejects_negative_amount() {
+    let err = split_vat_signed(-1, dec!(0.25)).unwrap_err();
+    assert!(matches!(err, VatError::NegativeAmount));
+}
+```
+
+`#[should_panic(expected = "...")]` is for genuine panics only — invariant violations,
+not expected error paths. A function whose contract includes "rejects negative input"
+should return `Err`, not panic, and a test that accepts a panic hides that design choice.
+
+## Gates
+
+```bash
+cargo test                    # the failing test
+cargo clippy -- -D warnings   # static gate, same phase as RED
+cargo fmt --check
+```
+
+`cargo test` compiles in debug, so integer overflow panics rather than wrapping — a
+release build will not. Where overflow matters, test the checked path explicitly
+(`checked_mul`), or you are testing debug-only behaviour.
+
+For unsafe code, `cargo +nightly miri test` is the nearest thing to Go's `-race`.
+Safe-only crates have no equivalent and should strike that checklist box deliberately.

skills/tdd/references/typescript.md

@@ -0,0 +1,85 @@
+# TDD in TypeScript
+
+The Iron Law and Red-Green-Refactor in `SKILL.md` apply unchanged. This file replaces
+the Go-Specific TDD Notes for TypeScript.
+
+Vitest is the default; Jest differs only in imports and a few matcher names, both noted
+where it matters.
+
+## The first red is a resolution error, and that is correct
+
+```
+Error: Failed to resolve import "./vat" from "src/vat.test.ts"
+```
+
+Legitimate. Do not create an empty module or a stub throwing `new Error("not
+implemented")` to get past collection — that is production code before a failing test.
+
+## Table-driven: `it.each`
+
+```ts
+describe('splitVat', () => {
+  it.each([
+    { amountMinor: 14,    rate: 0.12, expected: [12, 2],        name: 'tie rounds down to even' },
+    { amountMinor: 42,    rate: 0.12, expected: [38, 4],        name: 'tie rounds up to even' },
+    { amountMinor: 12500, rate: 0.25, expected: [10000, 2500],  name: 'exact division' },
+  ])('$name', ({ amountMinor, rate, expected }) => {
+    expect(splitVat(amountMinor, rate)).toEqual(expected)
+  })
+})
+```
+
+`$name` interpolates into the test title, which is the `t.Run` analogue. Prefer the
+object form over the array form — a positional tuple with five entries is unreadable at
+the point of failure.
+
+**Do not port Go's `wantErr` column.** Error cases get their own test:
+
+```ts
+it('rejects a negative amount', () => {
+  expect(() => splitVat(-1, 0.25)).toThrow(/must be non-negative/)
+})
+
+it('rejects a negative amount (async)', async () => {
+  await expect(splitVat(-1, 0.25)).rejects.toThrow(/must be non-negative/)
+})
+```
+
+The `await` on the async form is load-bearing. Without it the assertion returns a
+promise nobody checks, the test passes, and it will keep passing after you break the
+code. This is the single most common false-green in a TypeScript suite.
+
+## `tsc --noEmit` is part of RED
+
+A red type-check is a red build:
+
+```bash
+npx vitest run src/vat.test.ts     # the failing test
+npx tsc --noEmit                   # same gate, same phase
+```
+
+Vitest transpiles without type-checking, so a suite can be green while the code does not
+compile. `tsc --noEmit` is not optional here — it is the half of the gate the runner
+does not perform.
+
+## Equality matchers are not interchangeable
+
+- `toBe` — `Object.is`. For primitives and identity.
+- `toEqual` — structural, and **ignores `undefined` properties**: `{a: 1, b: undefined}`
+  equals `{a: 1}`. That is a real hole when the bug you are hunting is a missing field.
+- `toStrictEqual` — structural, respects `undefined`, and checks class identity. Default
+  to this one; reach for `toEqual` deliberately.
+
+## Mocks
+
+`vi.mock` (Jest: `jest.mock`) is hoisted above imports, so a factory referencing an
+outer variable throws at runtime. Use `vi.hoisted` when the mock needs shared state.
+Per `SKILL.md`, mock only across a system boundary — a mocked module you own is a test
+of your mock.
+
+## Async and fake timers
+
+- `vi.useFakeTimers()` needs a matching `vi.useRealTimers()` in teardown, or the next
+  file inherits frozen time and fails somewhere unrelated.
+- Prefer condition polling (`await vi.waitFor(...)`) over a fixed `setTimeout` — an
+  arbitrary wait is a flake with a schedule.