Plugin architecture internals

For the public capability model, plugin shapes, and ownership/execution contracts, see Plugin architecture. This page covers the internal mechanics: load pipeline, registry, runtime hooks, Gateway HTTP routes, import paths, and schema tables.

What each page covers

• Load pipeline and registry — discovery, safety gates, manifest-first metadata, the plugin cache boundary, and the registry model.
• Provider hooks and catalogs — the provider hook order table, a worked example, bundled hook shapes, and catalog merge order.
• Core runtime helpers — speech, media understanding, subagent, web search, and image generation through api.runtime.
• Gateway routes — plugin HTTP endpoints and their auth, scope, replacement, and admission rules.
• Channel surfaces — conversation binding callbacks, message tool schemas, target resolution, directories, and inspection.
• Packs and import paths — SDK import subpaths, package packs, and channel catalog and install metadata.
• Context engines — replacing session ingest, assembly, and compaction through the contextEngine slot.
• New capability — the sequence, file checklist, and contract-test pattern for a capability core does not have yet.

Where each section moved

Every section of the single-page version now lives on this page or on one of the eight child pages below. The anchors from the single-page version still resolve here.

Load pipeline and registry

Load pipeline and registry — Discovery, safety gates, manifest-first metadata, the plugin cache boundary, and the registry core reads from.

• Load pipeline
• Manifest-first behavior
• Plugin cache boundary
• Registry model

Provider hooks and catalogs

Provider hooks and catalogs — The provider hook order table, a worked provider example, bundled hook shapes, and model catalog registration.

• Provider runtime hooks
• Hook order and usage
• Provider example
• Built-in examples
• Pass-through catalog providers
• OAuth and usage endpoint providers
• Replay and transcript cleanup families
• Catalog-only providers
• Anthropic-specific stream helpers
• Provider catalogs

Core runtime helpers

Core runtime helpers — Speech, media understanding, subagent, web search, and image generation helpers exposed through api.runtime.

• Runtime helpers
• api.runtime.imageGeneration

Gateway routes

Gateway routes — Registering plugin HTTP endpoints on the Gateway, and their auth, scope, replacement, and admission rules.

• Gateway HTTP routes

Channel surfaces

Channel surfaces — Conversation binding callbacks, message tool schemas, target resolution, config-backed directories, and read-only inspection.

• Conversation binding callbacks
• Message tool schemas
• Channel target resolution
• Config-backed directories
• Read-only channel inspection

Packs and import paths

Packs and import paths — Plugin SDK import subpaths, multi-extension package packs, and channel catalog and install metadata.

• Plugin SDK import paths
• Package packs
• Channel catalog metadata

Context engines

Context engines — Taking over session ingest, assembly, and compaction through the contextEngine slot.

• Context engine plugins

New capability

New capability — The sequence, file checklist, and contract-test pattern for adding a capability the plugin API does not have yet.

• Adding a new capability
• Capability checklist
• Capability template

Related

• Plugin architecture — public capability model and shapes
• Plugin SDK subpaths
• Plugin SDK setup
• Building plugins