| OpenAPI Object | Root object, openapi, $self, info, servers, paths, webhooks, components, security, tags | core-openapi-object |
| Format & Structure | JSON/YAML, case sensitivity, rich text, OAD structure, parsing, base URI | core-format-and-structure |
| Fixed & Patterned Fields | Fixed vs patterned fields, paths keys, components keys, extensions (x-) | core-fixed-patterned-fields |
| Info & Metadata | Info, Contact, License objects | core-info-metadata |
| Server | Server Object, Server Variable, URL templating | core-server |
| Paths & Operations | Paths Object, Path Item, Operation Object, additionalOperations, query | paths-and-operations |
| Path Templating | Path templating, path parameters, matching, ABNF | core-path-templating |
| Parameters | Parameter Object, in (path/query/header/cookie/querystring), style, schema vs content | parameters |
| Request Body & Media Type | Request Body, Media Type Object, sequential media types, itemSchema | request-body-and-media-type |
| Encoding Object | Encoding by name/position, contentType, style, explode, form, multipart | core-encoding-object |
| Media Types | Content keys, media type ranges, OpenAPI Media Type Registry | core-media-types |
| Responses | Responses Object, Response Object, headers, content, links | responses |
| HTTP Status Codes | Response keys, default, 1XX–5XX range with X | core-http-status-codes |
| Schema & Components | Schema Object (JSON Schema 2020-12), Components, $ref resolution | schema-and-components |
| Schema JSON Schema Keywords | JSON Schema 2020-12 keywords and OAS extensions in Schema | schema-json-schema-keywords |
| Schema Composition & Polymorphism | allOf, oneOf, anyOf, discriminator | schema-composition-polymorphism |
| Data Types & Formats | JSON Schema types, format keyword, OAS dialect | core-data-types-and-formats |
| Discriminator & XML | Discriminator Object, XML Object (nodeType, name, namespace) | core-discriminator-and-xml |
| Components Reuse | Reusing parameters, responses, schemas via $ref | components-reuse |
| Reference Object | $ref, summary/description override, resolution rules | core-reference-object |
| Header Object | Response/multipart headers, style simple, Set-Cookie, Link | core-header-object |
| Example Object | dataValue, serializedValue, value, externalValue, Working with Examples | core-example-object |
| Tag & External Docs | Tag Object, External Documentation Object, parent, kind | core-tags-and-external-docs |
| Link Object | operationRef, operationId, parameters, requestBody | core-link-object |
| Runtime Expressions | $request, $response, $url, $method, ABNF, Link/Callback usage | core-runtime-expressions |
| Security | Security Scheme, OAuth Flows, Security Requirement Object | security |
| Security Scheme Types | apiKey, http (basic/bearer), mutualTLS, oauth2, openIdConnect | security-scheme-types |
| Security Requirement Object | OR/AND semantics, {} optional, [] clear, scopes | security-requirement-object |
| OAuth2 Flows | OAuth Flows Object, OAuth Flow Object, authorizationCode, deviceAuthorization | security-oauth2-flows |
| Callbacks & Webhooks | Callback Object, webhooks | callbacks-and-webhooks |
| Extensions | Specification extensions (x-), extension registries | advanced-extensions |