Extensibility section of Encyclopedia

Author: drewhoskins-temporal

docs/develop/plugins-guide.mdx

@@ -36,9 +36,6 @@ Here are some common use cases for plugins:
 The recommended way to start building plugins is with a `SimplePlugin`. This abstraction will tackle the vast majority
 of plugins people want to write.
 
-For advanced use cases, you can extend the methods in lower-level classes that Simple Plugin is based on without
-re-implementing what you’ve done. See the [Advanced Topics section](#advanced-topics-for-plugins) for more information.
-
 ### Example Plugins
 
 If you prefer to learn by getting hands-on with code, check out some existing plugins.

docs/encyclopedia/extensibility.mdx

@@ -0,0 +1,23 @@
+---
+id: extensibility
+title: Extensibility
+sidebar_label: Extensibility
+description: Temporal offers mechanisms to augment the functionality of Workflows and Activities, including data conversion, context propagation, interceptors, and plugins.
+toc_max_heading_level: 4
+keywords:
+  - extensibility
+  - interceptors
+  - context propagation
+  - data conversion
+  - plugins
+tags:
+  - Concepts
+---
+
+Temporal offers many mechanisms to augment the functionality of Workflows and Activities.
+These allow you to customize how data is serialized, propagate metadata across execution boundaries, and inject cross-cutting behavior like tracing and logging.
+
+- [Data Conversion](/dataconversion) - Customize how arguments and return values are serialized, compressed, or encrypted
+- [Context Propagation](/encyclopedia/context-propagation) - Pass custom metadata (tracing IDs, tenant IDs, auth tokens) across Workflow, Activity, and Child Workflow boundaries
+- [Interceptors](/encyclopedia/interceptors) - Add cross-cutting behavior (observability, authorization, header manipulation) before and after SDK operations
+- [Plugins](/encyclopedia/plugins) - Bundle interceptors, context propagators, data converters, and built-in definitions into reusable packages

docs/encyclopedia/index.mdx

@@ -24,7 +24,7 @@ The following Encyclopedia pages describe the concepts, components, and features
 - [Temporal Service](/temporal-service)
 - [Namespaces](/namespaces)
 - [Temporal Nexus](/nexus)
-- [Data conversion](/dataconversion)
+- [Extensibility](/encyclopedia/extensibility)
 
 For a complete list of Temporal terms, see the [Glossary](/glossary).
 

docs/encyclopedia/interceptors.mdx

@@ -0,0 +1,30 @@
+---
+id: interceptors
+title: Interceptors
+sidebar_label: Interceptors
+description: Add cross-cutting behavior like observability, authorization, and header manipulation before and after SDK operations.
+toc_max_heading_level: 4
+keywords:
+  - interceptors
+  - middleware
+  - observability
+  - tracing
+tags:
+  - Concepts
+---
+
+Interceptors let you add cross-cutting behavior before and after SDK operations such as starting a Workflow, executing an Activity, or handling a Signal. They work like middleware: each interceptor wraps the next, forming a chain that executes around the underlying operation.
+
+Common use cases:
+
+- Observability (logging, metrics, tracing)
+- Authorization and authentication checks
+- Header manipulation (propagating metadata)
+- Input/output validation
+
+## Implementing Interceptors
+
+Here are SDK-specific guides:
+
+- [Python](/develop/python/interceptors)
+- [TypeScript](/develop/typescript/interceptors)

docs/encyclopedia/plugins.mdx

@@ -0,0 +1,26 @@
+---
+id: plugins
+title: Plugins
+sidebar_label: Plugins
+description: Bundle interceptors, context propagators, data converters, and built-in definitions into reusable packages.
+toc_max_heading_level: 4
+keywords:
+  - plugins
+  - simple plugin
+  - extensibility
+tags:
+  - Concepts
+---
+
+A Plugin bundles multiple extensibility primitives - interceptors, context propagators, data converters, and built-in Workflow/Activity/Nexus definitions - into a single reusable package. Plugins let platform teams and library authors ship ready-made functionality that application developers can adopt with a single registration call.
+
+Common use cases:
+
+- AI Agent SDKs (e.g., OpenAI Agents, Pydantic AI)
+- Observability packages (tracing, logging, metrics)
+- Encryption or compliance middleware
+- Shared infrastructure integrations (messaging, payments, LLM calls)
+
+## Implementing Plugins
+
+See the [Plugins guide](/develop/plugins-guide) for how to build and use plugins across all supported SDKs.

sidebars.js

@@ -851,23 +851,36 @@ module.exports = {
         },
         {
           type: 'category',
-          label: 'Data Conversion',
+          label: 'Extensibility',
           collapsed: true,
           link: {
             type: 'doc',
-            id: 'encyclopedia/data-conversion/dataconversion',
+            id: 'encyclopedia/extensibility',
           },
           items: [
-            'encyclopedia/data-conversion/default-custom-data-converters',
-            'encyclopedia/data-conversion/payload-converter',
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-            'encyclopedia/data-conversion/failure-converter',
-            'encyclopedia/data-conversion/remote-data-encoding',
-            'encyclopedia/data-conversion/codec-server',
-            'encyclopedia/data-conversion/key-management',
+            {
+              type: 'category',
+              label: 'Data Conversion',
+              collapsed: true,
+              link: {
+                type: 'doc',
+                id: 'encyclopedia/data-conversion/dataconversion',
+              },
+              items: [
+                'encyclopedia/data-conversion/default-custom-data-converters',
+                'encyclopedia/data-conversion/payload-converter',
+                'encyclopedia/data-conversion/payload-codec',
+                'encyclopedia/data-conversion/failure-converter',
+                'encyclopedia/data-conversion/remote-data-encoding',
+                'encyclopedia/data-conversion/codec-server',
+                'encyclopedia/data-conversion/key-management',
+              ],
+            },
+            'encyclopedia/context-propagation',
+            'encyclopedia/interceptors',
+            'encyclopedia/plugins',
           ],
         },
-        'encyclopedia/context-propagation',
         'web-ui',
       ],
     },