rat-stack-mode

# Work in rat-stack mode [AGENTS.md](/AGENTS.md) is law. [VISION.md](/VISION.md) sets the intent, reliability goals, scope, package-removal test, and shrinking debt. Use this skill to choose playbooks under those rules. A capability is one named action with shared value definitions and a server-side implementation. A cartridge is a package for one job with its implementation and required infrastructure. ## Non-negotiables - Start a todo list with reading the principles index below. - Open every leaf that bears on a decision. Report which rules changed which choices. - Name the data shape, authoritative store, copies calculated from it, and writer before writing code. - Reuse stores when their facts and operation guarantees fit. Reporting does not justify gating unrelated execution. - Measure before setting a timeout, rate cap, batch size, or concurrency limit. Put the baseline first; requested values remain hypotheses. ## Principles index Leaves live in the repo; read them from a checkout. **Product and UX** - `skills/rat-stack-mode/principles/judge-through-the-person.md`: changing an interface or user-visible behavior. - `skills/rat-stack-mode/principles/keep-boundary-words-honest.md`: naming failures, outcomes, and public claims. **Architecture** - `skills/rat-stack-mode/principles/one-contract-many-projections.md`: adding actions for agents or browser clients. - `skills/rat-stack-mode/principles/keep-the-stack-floor.md`: choosing runtime patterns, infrastructure, and validation. - `skills/rat-stack-mode/principles/prove-move-delete.md`: replacing an internal API or implementation. - `skills/rat-stack-mode/principles/use-real-provider-guarantees.md`: choosing an adapter or testing its behavior. - `skills/rat-stack-mode/principles/gates-guard-invariants.md`: adding a gate or approval check. - `skills/rat-stack-mode/principles/keep-unknown-distinct.md`: handling crashes, refusal, or missing results. **Data and truth** - `skills/rat-stack-mode/principles/name-the-system-of-record.md`: adding stores, caches, aggregates, or nightly reports. - `skills/rat-stack-mode/principles/store-source-facts.md`: capturing observations or interpreting missing fields. - `skills/rat-stack-mode/principles/keep-execution-receipts.md`: recording runs or claiming an operation succeeded. - `skills/rat-stack-mode/principles/scope-private-data.md`: handling identities, credentials, logs, or analytics. - `skills/rat-stack-mode/principles/version-content-artifacts.md`: writing public content or quoting code. - `skills/rat-stack-mode/principles/no-dual-writes.md`: copying a fact across stores or maintaining a read model. - `skills/rat-stack-mode/principles/validate-before-durable-write.md`: recording rows, events, or snapshots. - `skills/rat-stack-mode/principles/bound-every-read.md`: listing, querying, exporting, or rebuilding data. - `skills/rat-stack-mode/principles/one-writer-per-partition.md`: updating shared mutable state. - `skills/rat-stack-mode/principles/make-operations-idempotent.md`: replaying commands or recovering after crashes. - `skills/rat-stack-mode/principles/subtract-before-you-add.md`: sequencing new work or removing unused interfaces. **Verification** - `skills/rat-stack-mode/principles/check-the-actual-artifact.md`: finishing work or reviewing another agent's result. - `skills/rat-stack-mode/principles/prove-the-recipient-path.md`: changing runtime wiring or deployed interfaces. - `skills/rat-stack-mode/principles/tests-detect-broken-behavior.md`: adding tests or judging their coverage. - `skills/rat-stack-mode/principles/find-the-cause-first.md`: fixing failures or slow runs. - `skills/rat-stack-mode/principles/rebuild-what-you-run.md`: running or debugging an artifact someone else built. - `skills/rat-stack-mode/principles/measure-real-limits.md`: setting budgets or diagnosing contention. **Agents** - `skills/rat-stack-mode/principles/look-it-up-first.md`: entering unfamiliar code or deciding whether to ask. - `skills/rat-stack-mode/principles/ask-one-material-question.md`: reaching a decision that needs owner sign-off. - `skills/rat-stack-mode/principles/separate-writers-verify-readers.md`: dividing work or accepting delegated results. - `skills/rat-stack-mode/principles/encode-lessons-in-structure.md`: correcting a repeated bad pattern. **Prose and visual** - `skills/rat-stack-mode/principles/use-plain-language.md`: writing docs, skills, or system pages. - `skills/rat-stack-mode/principles/design-serves-function.md`: changing layout, focus, or visual emphasis. - `skills/rat-stack-mode/principles/make-review-views-complete.md`: rendering evidence for people and agents. **Cost and speed** - `skills/rat-stack-mode/principles/optimise-the-whole-loop.md`: changing builds, tests, generation, or feedback time. ## Playbooks Match every applicable playbook; a capability with new persistence matches capability and store playbooks. Open each match and copy its steps into the todo list before task-specific steps. For unnumbered skills, copy action lists; keep skipped steps as `skip: <reason>`. Finish with each matching playbook's report requirements. - New action: [add-a-capability](/skills/add-a-capability). - States, retries, or cancellation: [add-a-lifecycle-machine](/skills/add-a-lifecycle-machine). - New persistence: [add-a-store](/skills/add-a-store). - Public prose or skill pages: [write-a-wiki-page](/skills/write-a-wiki-page). - Package or interface choices: [keep-or-cut](/skills/keep-or-cut). - Stateful design, replacement, or read-model design: [uncomplect](/skills/uncomplect). - Pins, recurring bad patterns, or repository maintenance: [gardener](/skills/gardener). - Peer research or shared dependency updates: [find-peers](/skills/find-peers). - Cloud resources or unfamiliar deployment wiring: [learn-alchemy](/skills/learn-alchemy). - Unfamiliar stack integration: [learn-rat-stack](/skills/learn-rat-stack). - Crashes, flaky tests, wrong output, or slow runs: [investigate-a-failure](/skills/investigate-a-failure). `write-a-query`, `add-a-read-model`, and `explore-limits` are planned. Use applicable leaves and existing playbooks; identify uncovered steps explicitly. ## Autonomy and child-project slots Follow AGENTS.md's **Boundaries and sign-off** for autonomy. In a child project, name production write authority, deploy gates, and the model roster here and in AGENTS.md. Router and adapted principles credit pstack by Lauren Tan (MIT, `skills/rat-stack-mode/LICENSE-pstack`).