HarperFast · kylebernhardy · Jul 24, 2026 · Jul 24, 2026 · Jul 24, 2026 · Jul 24, 2026
@@ -101,7 +101,7 @@ MCP `tools/list` now returns:
 }
 ```
 
-And `/openapi.json` picks up the same data: schema-level `description`, per-property `description`, and prepended path-level descriptions for every verb on `/Product`.
+And `/openapi` picks up the same data: schema-level `description`, per-property `description`, and prepended path-level descriptions for every verb on `/Product`.
 
 ### `search_*` gets typed and described too
 
@@ -126,6 +126,10 @@ export class ProductInventory extends Resource {
 		'Aggregate inventory analytics computed over the Product catalog. ' +
 		'Read-only; the underlying Product table is the system of record.';
 
+	// The fragment flag below types MCP's `id` argument; this class static is what the
+	// OpenAPI path parameter and the tool-description sentence read. Declare both.
+	static primaryKey = 'sku';
+
 	static properties = {
 		sku: { type: 'string', primaryKey: true, description: 'Stock keeping unit; matches Product.sku.' },
 		onHand: { type: 'integer', description: 'Current warehouse count.' },
@@ -137,15 +141,73 @@ export class ProductInventory extends Resource {
 		},
 	};
 
-	async get(id) {
+	static async get(target) {
 		/* returns { sku, onHand, reserved, stockStatus } */
 	}
-	async search(query) {
+	static async search(query) {
 		/* ... */
 	}
 }
 ```
 
+<VersionBadge type="changed" version="v5.2.0" /> — MCP `tools/list` returns the same shape a table-backed Resource
+produces — types, per-property descriptions, and the `enum` — instead of an empty property set:
+
+```json
+{
+	"name": "get_ProductInventory",
+	"description": "Aggregate inventory analytics computed over the Product catalog. Read-only; the underlying Product table is the system of record.\n\nFetches a single ProductInventory record by sku. Runtime RBAC (allowGet) enforces per-record access at call time.",
+	"inputSchema": {
+		"type": "object",
+		"properties": {
+			"id": { "type": "string", "description": "Primary key (sku)." },
+			"get_attributes": {
+				"type": "array",
+				"items": { "type": "string" },
+				"description": "Attribute names to project; defaults to all readable attributes."
+			}
+		},
+		"required": ["id"]
+	},
+	"outputSchema": {
+		"type": "object",
+		"properties": {
+			"sku": { "type": "string", "description": "Stock keeping unit; matches Product.sku." },
+			"onHand": { "type": "integer", "description": "Current warehouse count." },
+			"reserved": { "type": "integer", "description": "Units allocated to open orders but not yet shipped." },
+			"stockStatus": {
+				"type": "string",
+				"enum": ["in_stock", "out_of_stock", "backorder"],
+				"description": "Derived from onHand vs reserved."
+			}
+		},
+		"required": ["sku"],
+		"additionalProperties": false
+	},
+	"annotations": { "readOnlyHint": true }
+}
+```
+
+`/openapi` picks up the same properties. Two things this does _not_ reach: `harper://schema/{db}/{table}` is keyed by database and table name, so a Resource with no backing table never appears there; and only `get_*` carries a record-shaped `outputSchema` — `search_*` has none, and the write verbs advertise fixed `{ id }` / `{ ok }` / `{ deleted }` envelopes.
+
+The `"record by sku"` phrasing above and the OpenAPI path parameter both come from that `static primaryKey`, not from the fragment's `primaryKey: true`. Omit it and you get `/ProductInventory/{id}` and "…record by id" while MCP's `id` argument still describes itself as the `sku`.
+
+### Watch the vocabulary: lowercase JSON Schema, not GraphQL
+
+`static properties` is JSON Schema. Types are lowercase — `string`, `integer`, `number`, `boolean`, `object`, `array`, `null`. Harper also recognizes the capitalized GraphQL names (`String`, `Int`, `Long`) you write in a `.graphql` schema, so those still map correctly. The hazard is a name in neither vocabulary — `'Text'`, `'Object'`, `'Array'` — where MCP quietly coerces to `{ type: 'string' }` and OpenAPI emits an untyped `{}`. Sticking to the lowercase names keeps the two surfaces in agreement.
+
+Beyond `type` and `description`, the fragments carry `enum` / `format` / `const` for value constraints, `items` for arrays (including arrays of objects), and `properties` / `required` / `additionalProperties` for nested objects. Those hints reach both surfaces at the top level; inside a nested object or an array's `items`, MCP keeps them and OpenAPI drops them.
+
+One spelling difference worth knowing: Harper's OpenAPI document declares 3.0.3, which predates JSON Schema's `const` keyword, so a `const` fragment reaches Swagger UI as an equivalent single-value `enum`. Write `const`; expect `enum: [value]` in the OpenAPI output. See the [Resource API reference](/reference/v5/resources/resource-api#static-properties-recordstring-jsonschemafragment) for the full key list and how unions and item-less arrays resolve.
+
+### Authoring rubric, Path B edition
+
+- **Describe every property.** The rubric from Path A applies verbatim — meaning over type, units and formats spelled out, short.
+- **Use `enum` wherever the value set is closed.** It's the single highest-leverage hint for an LLM: it turns "pass a status string" into "pass one of these four."
+- **Add `format`** (`date-time`, `uuid`, `email`, ...) where it applies. It reaches Swagger UI and gives the LLM a concrete shape to emit.
+- **Declare a `primaryKey` property _and_ `static primaryKey`.** The fragment flag types and describes the `id` argument on `get_*` / `update_*` / `delete_*`; the class static drives the OpenAPI path parameter and the tool-description sentence.
+- **Reach for `static outputSchemas`** when a verb returns something other than the full record — `get_*` is the only verb whose output schema is derived from `static properties`, so this is how you describe what `create_*` or a custom `search_*` actually returns.
+
 See the [Resource API reference](/reference/v5/resources/resource-api#class-level-metadata-for-mcp-and-openapi) for the full surface, including `static outputSchemas` for per-verb projection overrides, `static hidden` for full suppression, and `static mcp` for narrow MCP-only annotation overrides.
 
 ## Inheritance: extending a table
@@ -170,7 +232,7 @@ The author writes against the canonical `properties` API. Internal code paths th
 
 ## Hiding sensitive fields with `@hidden`
 
-OpenAPI is typically exposed to anyone reachable on the HTTP port — there's no per-user filtering on `/openapi.json`. A docstring on a sensitive field publishes that text to anyone who can hit the endpoint. The `@hidden` directive suppresses a field (or an entire type) from both MCP and OpenAPI without affecting data access:
+The OpenAPI document is global: there is no per-user filtering on `/openapi`, so every caller who can fetch it sees the same schemas and the same docstrings. Whether an unauthenticated caller can fetch it at all depends on your instance's authentication configuration — a default `prod` install returns `403` without credentials — but treat any field you document as visible to every user who can reach the endpoint, not just those with permission to read it. The `@hidden` directive suppresses a field (or an entire type) from both MCP and OpenAPI without affecting data access:
 
 ```graphql
 type Customer @table @export {
@@ -190,13 +252,15 @@ type Customer @table @export {
 
 ## RBAC and per-user filtering
 
-For MCP tool descriptors, `attribute_permissions` already filters the schema per-user — an attribute the caller cannot read is dropped from that user's view of the tool descriptor, along with its description. The new metadata flows through the existing pipeline.
+MCP tool schemas are derived once at registration time and are the same for every caller — `attribute_permissions` is enforced when the tool is called, not reflected in the advertised `inputSchema` / `outputSchema`. What RBAC does filter is the tool _list_: `tools/list` omits tools the caller has no permission for on the backing table. Treat a descriptor's property descriptions as visible to any authenticated MCP client, and use `@hidden` for anything that shouldn't be.
 
 For OpenAPI, the document is global and not per-user filtered. Use `@hidden` (or `static hidden`) to control what surfaces there.
 
 ## Verifying the end-to-end flow
 
-1. Add `"""docstrings"""` to a `@table @export` type and save your component.
+1. Add `"""docstrings"""` to a `@table @export` type — or `static description` + `static properties` to a programmatic Resource — and save your component.
 2. Hit MCP `tools/list` for the application profile — confirm `get_*`, `search_*`, etc. descriptions include the type docstring and per-attribute descriptions are present in the `inputSchema` and `outputSchema`.
-3. Hit `/openapi.json` on the application HTTP port — confirm the path-level descriptions and per-property descriptions show up in Swagger UI / Redoc.
+3. Hit `/openapi` on the application HTTP port — confirm the path-level descriptions and per-property descriptions show up in Swagger UI / Redoc.
 4. Add `@hidden` to an attribute — confirm it disappears from both surfaces while remaining queryable via direct REST/SQL.
+
+Two things to check for a programmatic Resource in step 2. An empty `properties: {}` on the `get_*` output schema means the fragments never resolved — most often because the class also carries a non-empty `attributes` Array, which wins. Properties named `0`, `1`, `2`… mean `static properties` was declared as an array instead of a `Record` keyed by property name. And if the tools don't appear in `tools/list` at all, check whether you're authenticated as a super-user — see the listing-visibility note in the [Resource API reference](/reference/v5/resources/resource-api#static-properties-recordstring-jsonschemafragment).
@@ -46,7 +46,7 @@ Wraps Harper's operation catalog (the same set of operations the REST `/operatio
 Walks your application's exported `Resource` classes and generates one MCP tool per implemented REST verb. Mounts on the **application HTTP server** (the same listener that serves your REST endpoints).
 
 - For each exported Resource, Harper emits `get_<name>`, `search_<name>`, `create_<name>`, `update_<name>`, and `delete_<name>` tools when the corresponding verb is implemented on the prototype.
-- Input schemas are derived from `Table.attributes` and narrowed by your role's `attribute_permissions`.
+- Input schemas are derived from `Table.attributes`, or from a programmatic Resource's `static properties` <VersionBadge type="changed" version="v5.2.0" /> when it declares no attributes. They are built once at registration and are identical for every caller — `attribute_permissions` is enforced at call time and filters which tools `tools/list` returns, not the schemas themselves.
 - Components can opt non-verb instance methods into the MCP surface by declaring a static `mcpTools` array on the Resource class.
 - A Resource is excluded from the MCP surface when its registration sets `exportTypes.mcp = false`.
 

@@ -48,15 +48,17 @@ Operations registered outside core (for example, `cluster_status` from harper-pr
 
 For verb tools generated from exported Resources:
 
-| Field                         | Source                                                                                                                                                                                         |
-| ----------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| `name`                        | `${verb}_${sanitized-path}` (e.g. `get_Product`, `search_Customer`)                                                                                                                            |
-| `description`                 | Composed: `[ResourceClass.description \n\n] ${verb sentence} ${runtime RBAC note}`                                                                                                             |
-| `inputSchema`                 | Derived per verb from `ResourceClass.attributes` and the caller's `attribute_permissions`. Per-attribute `description` propagates to `inputSchema.properties[*].description`                   |
-| `outputSchema`                | Derived per verb from `ResourceClass.attributes` for `get_*` / `create_*` / `update_*` / `patch_*`. `delete_*` returns `{ deleted: true, <pk> }`. `search_*` deliberately omits `outputSchema` |
-| `annotations.readOnlyHint`    | `true` on `get_*` and `search_*`                                                                                                                                                               |
-| `annotations.destructiveHint` | `true` on `delete_*`                                                                                                                                                                           |
-| `annotations.idempotentHint`  | `true` on `update_*` (PUT semantics); other verbs default off                                                                                                                                  |
+| Field                         | Source                                                                                                                                                                                          |
+| ----------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `name`                        | `${verb}_${sanitized-path}` (e.g. `get_Product`, `search_Customer`)                                                                                                                             |
+| `description`                 | Composed: `[ResourceClass.description \n\n] ${verb sentence} ${runtime RBAC note}`                                                                                                              |
+| `inputSchema`                 | Derived per verb from the Resource's schema (below), once at registration time and identical for every caller. Per-property `description` propagates to `inputSchema.properties[*].description` |
+| `outputSchema`                | The full record shape on `get_*`; fixed envelopes on `create_*` (`{ id }`), `update_*` / `patch_*` (`{ ok }`), and `delete_*` (`{ deleted }`). `search_*` deliberately omits `outputSchema`     |
+| `annotations.readOnlyHint`    | `true` on `get_*` and `search_*`                                                                                                                                                                |
+| `annotations.destructiveHint` | `true` on `delete_*`                                                                                                                                                                            |
+| `annotations.idempotentHint`  | `true` on `update_*` (PUT semantics); other verbs default off                                                                                                                                   |
+
+The schema source is the Resource's table-derived attributes when it has them, and its `static properties` declaration when it doesn't — a programmatic Resource declaring only `static properties` yields the same rich `inputSchema` / `outputSchema` as a table-backed one <VersionBadge type="changed" version="v5.2.0" />. `static properties` uses JSON Schema types (lowercase), including `enum`, `format`, `const`, arrays, and nested objects; see the [Resource API reference](/reference/v5/resources/resource-api#static-properties-recordstring-jsonschemafragment).
 
 `static description` and `static properties` on the Resource class override the auto-derived values. `static outputSchemas[verb]` overrides per-verb output schemas. `static mcp.annotations[verb]` overrides annotations per verb. `static hidden === true` suppresses the entire Resource from MCP listing.
 
@@ -139,7 +141,7 @@ Harper also publishes a small set of synthetic resources via the MCP `resources/
 | `harper://schema/{db}/{table}` | application | Per-table schema, filtered by `attribute_permissions` |
 | `https://{host}/{path}`        | application | Application HTTP Resources, in-process                |
 
-For `harper://schema/{db}/{table}` and `https://{host}/{path}` entries, the descriptor description prepends `Table.description` / `ResourceClass.description` when present.
+For `harper://schema/{db}/{table}` and `https://{host}/{path}` entries, the descriptor description prepends `Table.description` / `ResourceClass.description` when present. `harper://schema/{db}/{table}` is enumerated by database and table name, so a Resource that identifies no table is not listed there; for one that does, the schema body falls back to its `static properties` declaration when its `attributes` Array is empty <VersionBadge type="changed" version="v5.2.0" />.
 
 ## See also
 

@@ -72,7 +72,7 @@ The Resource's path is sanitized into a valid tool name: `/` and `.` become `_`.
 
 ### Input schema derivation
 
-Input schemas come from `Table.attributes`:
+Input schemas come from `Table.attributes` — or, for a programmatic Resource that declares no attributes, from its [`static properties`](/reference/v5/resources/resource-api#static-properties-recordstring-jsonschemafragment) <VersionBadge type="changed" version="v5.2.0" />, whose JSON Schema types pass through unchanged:
 
 - Harper types map to JSON Schema primitive types (`Int`/`Long`/`BigInt` → `integer`, `Float` → `number`, `String`/`ID` → `string`, `Boolean` → `boolean`, `Date` → `[string, number]`, `Bytes`/`Blob` → `string` with `contentEncoding: base64`).
 - Nested `Object` and `Array` attributes recurse into their `properties` / `elements`.