docs(agents): define OS_ env-var naming structure rule

AGENTS.md

@@ -63,7 +63,14 @@ Other scripts: `objectui:bump` (pull only), `objectui:build`, `objectui:clean`.
 6. **Object name = table name.** The object `name` is the canonical id everywhere (API, ObjectQL, REST, SDK, DB table). **Never** set `namespace` (deprecated) or `tableName` (always equals `name`). For module prefixes, embed in the name (`sys_user`, `ai_conversations`).
 7. **One Zod source per metadata type.** Each type (`view`, `flow`, `agent`, …) has exactly one schema in `packages/spec/src/{domain}/`. Org overlay opt-in lives only in `allowOrgOverride` on `DEFAULT_METADATA_TYPE_REGISTRY` — no parallel whitelists. See ADR-0005.
 8. **North Star alignment.** Read `content/docs/concepts/north-star.mdx` before structural changes. If a change doesn't advance §7 Built, shrink Drift, or unlock Missing — it probably shouldn't ship.
-9. **`OS_` env-var prefix.** All ObjectStack-owned env vars MUST start with `OS_`. When renaming a legacy var, use `readEnvWithDeprecation('OS_NEW', 'LEGACY')` from `@objectstack/types` (keeps legacy working one release). Third-party exceptions kept as-is: `NODE_ENV`, `HOME`, `OPENAI_API_KEY`, `TURSO_*`, OAuth `*_CLIENT_ID/SECRET`, `RESEND_API_KEY`, `POSTMARK_TOKEN`, `AI_GATEWAY_*`, `SMTP_*`. See #1382.
+9. **`OS_` env-var prefix + structure.** All ObjectStack-owned env vars MUST start with `OS_`, then follow **`OS_{DOMAIN}_{FEATURE}[_QUALIFIER]`** where `DOMAIN` is the subsystem (`AUTH`, `SEARCH`, `CORS`, `CLOUD`, `DATABASE`, `CLUSTER`, `MCP`, `SSO`, …) so related vars group together (cf. `OS_AUTH_*`, `OS_CORS_*`). Pick the shape by what the var *is*:
+   - **Boolean feature flag** → suffix **`_ENABLED`**, default-off / opt-in: `OS_{DOMAIN}_{FEATURE}_ENABLED` (`OS_SSO_ENABLED`, `OS_SCIM_ENABLED`, `OS_SEARCH_PINYIN_ENABLED`). Never a bare `OS_PINYIN_SEARCH` — bare names read as config, not toggles.
+   - **Config value** (URL / path / secret / level / count) → `OS_{DOMAIN}_{NAME}` (`OS_CLOUD_URL`, `OS_DATABASE_URL`, `OS_LOG_LEVEL`, `OS_AUTH_SECRET`).
+   - **Escape hatch / dangerous override** → **`OS_ALLOW_{X}`** — deliberately ungrouped and scary-looking (`OS_ALLOW_MAIN_EDITS`, `OS_ALLOW_MEMORY_CLUSTER_MULTINODE`).
+   - **Opt-out** → `OS_SKIP_{X}` / `OS_DISABLE_{X}`. **Test/CI-only** → `OS_TEST_*` / `OS_EXPECT_*`.
+   - Pre-existing vars that don't fit (`OS_METADATA_WRITABLE`, `OS_EAGER_SCHEMAS`, `OS_SERVER_TIMING`) are **debt, not precedent** — new vars follow this rule; rename old ones via the deprecation helper below when touched.
+
+   When renaming a legacy var, use `readEnvWithDeprecation('OS_NEW', 'LEGACY')` from `@objectstack/types` (keeps legacy working one release). Third-party exceptions kept as-is: `NODE_ENV`, `HOME`, `OPENAI_API_KEY`, `TURSO_*`, OAuth `*_CLIENT_ID/SECRET`, `RESEND_API_KEY`, `POSTMARK_TOKEN`, `AI_GATEWAY_*`, `SMTP_*`. See #1382.
 10. **File issues for out-of-scope findings — don't silently expand scope or leave them buried.** When you hit a bug, gap, or unenforced capability that's unrelated to the current task, or too large to fix in scope, open a GitHub issue (`gh issue create`) with a clear repro/decision and link it from your PR. Corollary: **never advertise or demo a capability the runtime doesn't actually deliver** (declared ≠ enforced) — fix it, trim it, or file an issue, but don't fake coverage. Example: the spec declares 9 validation-rule types but the write-path validator enforces only 3 (`state_machine`/`script`/`cross_field`); the other 6 are tracked in #1475 rather than demoed in the showcase.
 11. **Worktree-first — never edit on the shared `main` checkout.** This repo is edited by **multiple agents at once**; the shared `main` tree has its HEAD switched and reset *under you*, silently clobbering uncommitted work. Before your **first file edit**, you MUST be in a dedicated worktree on a feature branch: `git worktree add ../framework-<task> -b <branch> main && cd ../framework-<task> && pnpm install`. A PreToolUse hook (`.claude/hooks/guard-main-checkout.sh`) **enforces** this — it blocks `Edit`/`Write`/`NotebookEdit` whenever HEAD is on `main` (override for a deliberate non-task fix with `OS_ALLOW_MAIN_EDITS=1`). Full playbook below.
 12. **Contract-first — fix the metadata, not the runtime.** This is a metadata-driven framework: `packages/spec` is the one contract between metadata *producers* and the runtime/renderers that *consume* it. When a piece of metadata "doesn't work," ask **first**: *is it spec-compliant? is this the long-term-correct direction?* If the metadata is wrong, fix it at the **producer** and **reject it at authoring/publish** (validation / lint) so the error surfaces loudly — do **not** add a lenient alias or `??` fallback in the consumer (a node executor, the REST layer, a renderer) to tolerate off-spec input. A tolerant fallback fossilizes the wrong convention into a second de-facto contract, dilutes the spec, and hides the producer's bug — one strict contract beats N dialects. This is an **internal** contract (we own both ends), so "be liberal in what you accept" (Postel) does **not** apply — that's for untrusted boundaries. Change the **spec** only when the spec itself is genuinely wrong, and then deliberately (edit the Zod schema + migrate), never by accreting consumer-side fallbacks. The existing `cfg.filter ?? cfg.filters` / `cfg.objectName ?? cfg.object` in the flow executors are **debt to pay down, not a pattern to copy**. *Worked example:* an AI-authored `create_record` used `fieldValues` / `today()` / `{{trigger.record.id}}` while the executor reads `fields` / `{TODAY()}` / `{record.id}` → the fix was correcting the authoring skill + a publish-gate lint that rejects the wrong shape (cloud#688), **not** a `cfg.fields ?? cfg.fieldValues` runtime alias (framework#2419, rejected). Strengthens #5.