Agent-oriented reference for the OpenAPI Specification 3.2.0. Use when editing, generating, or validating OpenAPI descriptions (OAD).

When to Use

Authoring or updating OpenAPI 3.2 YAML/JSON documents
Resolving $ref, $self, and relative URIs in multi-document OADs
Describing paths, operations, parameters (query/path/header/cookie/querystring), request body, and responses
Using Schema Objects (JSON Schema Draft 2020-12 dialect), components, and references
Configuring security schemes (apiKey, http, mutualTLS, oauth2, openIdConnect) and requirements
Working with media types, encoding (form, multipart), and examples (dataValue/serializedValue/externalValue)

Core References

| 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

| Spec Authoring | operationId, tags, $self, components reuse, responses, security | best-practices-spec-authoring

| Base URI & Resolution | $self, retrieval URI, reference resolution, parsing guidance | advanced-base-uri-and-resolution

| Security Filtering | Empty Paths/Path Item, Security Considerations | advanced-security-filtering

OAS 3.2 root uses openapi: 3.2.0; at least one of components, paths, or webhooks MUST be present.
$self provides the document's base URI for reference resolution; use it in multi-document OADs.
Schema Object is a superset of JSON Schema Draft 2020-12; empty schema = true, none = false.
Parameter: use either schema+style or content (one Media Type); in: "querystring" requires content.
Security at root is OR (one of the Security Requirement Objects); per-operation overrides; {} = optional.