This file defines document structure, Markdown tiers, writing rules, and `verify-doc-budgets` ceilings. Use [dsh-doc-standards](../.agents/skills/dsh-doc-standards/SKILL.md) for placement and validation, and [dsh-prose-standard](../.agents/skills/dsh-prose-standard/SKILL.md) for required coverage and editorial judgment; the [doc-tiers Agent Note](../.agents/notes/implemented/process/2026-07-04-doc-tiers-and-budgets.md) owns rationale.
These rules apply to human-facing documentation; [Agent Notes](../.agents/notes/README.md) remain outside their scope. A [postmortem](postmortem/README.md) is an incident-scoped reference; chronology records evidence, not a teaching sequence. A document's subject and tree position fix its scope: describe its own subject at appropriate detail and direct children only by purpose, responsibility, and high-level behavior; link to the owning descendant for lower-level detail. Document type does not widen that scope. A reference may be exhaustive only about its own subject. Testing mechanisms, fixtures, and harnesses belong at the lowest owning level; higher documents link there.
Classify every in-scope document as a tutorial or reference. Tutorials follow an ordered path to an outcome and introduce only what each step needs. References define a lookup scope and current behavior without a teaching sequence. Separate substantial tutorial and reference content; label a section when either part is small.
Before writing a tutorial, privately classify the reader's starting knowledge and each concept as beginner, intermediate, or advanced. Establish prerequisites before dependent concepts, increase difficulty gradually, and move unnecessary advanced material to a later tutorial or reference.
Author in this order: locate the document in the tree; set its permitted detail; choose tutorial or reference; for a tutorial, order concepts by prerequisite and difficulty; relocate descendant-owned detail; replace lower-level explanations with links to their owners.
| Root `AGENTS.md` | Standing orders: rules an agent needs in context in every session, one to three lines each, linking its home | Stories, worked examples, situational procedures, anything restated from a linked home |
| [subsystems/](subsystems/README.md) | One reference page per subsystem: type definitions, semantics, and the generated Cordis API | Behavior narration (→ architecture.md) |
| [Agent Notes](../.agents/notes/README.md) | Active decision records: the why, what-was-given-up, and required verification; `implemented/` notes describe shipped reality in present tense | Migration plans, acceptance-task checklists, fixture walkthroughs, and spec-speak ("should…") once the decision has shipped; archived notes are frozen history, never current authority |
| [user/](user/index.md) | Product-facing guides published by the documentation website | Generated reference tables, contributor procedures, decision history |
| [development.md](development.md) | Contributor setup, daily workflow, and a summary of CI; a bilingual pair under the [i18n contract](i18n/README.md) | Runtime/version rationale (→ Agent Notes), check-by-check lists that drift from `package.json` scripts |
| Generated reference: the per-page `cordis-surface` regions in [subsystems/](subsystems/README.md), the [Cordis core API + inherited tier](cordis-api/context.md), [tool-catalog](tool-catalog.md), [config-catalog](config-catalog.md), [persistence-catalog](persistence-catalog.md), [module-graph.md](module-graph.md) | Exhaustive English sources regenerated from source and freshness-gated; reviewed Chinese counterparts follow the [pairing workflow](i18n/README.md#scope-and-exclusions) | Hand edits to generated English sources or regions; Chinese counterparts update through pairing only |
- **Document current state, not change history.** Avoid "previously/now/no longer", PRs, commits, and stack positions in durable prose; name the live mechanism. Put change stories in commits, PRs, Agent Notes, or postmortems; the latter two may cite merged PRs and issues as evidence.
- **Every non-trivial change includes at least one Agent Note in the same PR.** Update the owning note or add one; only mechanical/local edits are exempt ([scope](../.agents/notes/README.md#when-to-write-one)).
- **One physical line per paragraph** (`verify-md-wrap`): use editor soft-wrap. Code blocks, tables, and list structure keep their formatting; code comments stay under the linter's column limit.
- **Fenced `ts` blocks must compile** (`doc-typecheck`); a pasted type declaration and its original JSDoc use ` ```ts type-equiv `, while a body-stripped public class declaration uses ` ```ts public-api `; register either in the manifest so neither can drift ([mechanics](development.md#documenting-types-verbatim-ts-type-equiv)).
- **The owning [subsystems page](subsystems/README.md) updates in the same change** that reshapes a documented type. `verify-type-equiv` catches drifted pastes, not never-documented new types; a type is documented on its declaring package group's page ([page scoping](../.agents/notes/implemented/process/2026-08-03-package-anchored-subsystem-pages.md)).
- **Comments and JSDoc state complete contracts, not reasoning transcripts.** Preserve behavior, failure, timing, ownership, modality, exceptions, consequences, and non-obvious orientation; delete narration, test walkthroughs, review analysis, and code restatement. Keep the local contract and link its rationale. Use [dsh-prose-standard](../.agents/skills/dsh-prose-standard/SKILL.md) for details.
- Write directly: name actors and facts ([decision](../.agents/notes/implemented/process/2026-08-09-concrete-prose-names-actors-and-recorded-facts.md)). Reserve `seam` for the defined capability. Name the exact check, type, API, operation, or behavior instead of metaphorical "gate", "vocabulary", or "surface".
Ceilings are guardrails, not reduction targets. At or below target, retain at least 5% headroom; above target, freeze the ceiling until relocation or condensation brings the document under target. Lower a ceiling only when the document still has room, and raise it when content would otherwise be deleted. Targets: root `AGENTS.md` ≤ 1,600 words; `architecture.md` ≤ 1,800; subtree `AGENTS.md` ≤ 600, except `packages/AGENTS.md` ≤ 650 and this file ≤ 1,250; `packages/README.md` ≤ 600. Review governs unbudgeted tiers.
- Narrated history or war stories: "previously", "now", "no longer", "used to", "renamed", "was moved", PRs, or commits. State the current fact; link an Agent Note or postmortem when needed.
- Reasoning transcripts: step-by-step implementation narration, proof of obvious branches, test walkthroughs, or rejected local alternatives. Keep the resulting contract or durable rationale; delete the path used to derive it.
- Spec-speak in `implemented/` Agent Notes: "should", migration plans, acceptance checklists. An implemented Agent Note describes what is, per the [implemented-note instructions](../.agents/notes/implemented/AGENTS.md).
Link repository references with relative Markdown paths, never bare filenames or Agent Note numbers. `verify-md-links` rejects missing targets and dead `#fragment` anchors ([rationale](../.agents/notes/implemented/process/2026-06-18-markdown-cross-link-lint.md)).
