rpi-extensions

The host side of the plugin system: discovers, loads and drives Rust cdylib plugins, and bridges their tools and events into the runtime's native async types.

The ABI contract itself lives in rpi-plugin-sdk; this crate is the other half.

Install

[dependencies]
rpi-extensions = "0.3"

Most users never depend on this directly — the rpi CLI uses it, and the harness consumes its adapters through injection.

What it does

• Loading. load_one loads a single library, load_dir scans a directory, and load_session resolves the whole set for a session. Entrypoints are resolved unified → v3 → v2, so older plugins keep working.
• Registry. ExtensionRegistry holds what plugins registered: tools, providers, handlers, renderers and resource-discovery callbacks, with a deterministic snapshot the runtime can read.
• Tool bridge. PluginToolAdapter implements the agent's AgentTool trait on top of a plugin's four-function lifecycle (execute → poll → cancel → destroy). The blocking poll loop runs on spawn_blocking inside the ambient runtime — the adapter does not own a runtime of its own.
• Partial results. Tool progress flows back through an unbounded channel and is forwarded to on_update, behind a catch_unwind trampoline so a panicking callback cannot unwind across the FFI boundary.
• Lifecycle events. Dispatch wrappers for data, empty and lifecycle events, a veto path that lets a handler refuse startup, and a tee emitter so a plugin can observe events without stealing them from the TUI.
• Providers. PluggableProvider and ExtensionProviderHooks let a plugin serve a model or patch request options.

Crate dependencies

rpi-extensions depends on rpi-plugin-sdk, rpi-ai and rpi-agent only — never on rpi-harness. The harness receives these adapters as trait objects, so the dependency graph stays acyclic.

Where plugins are discovered

Installing and developing

rpi install my-extension                  # build from crates.io and install
rpi install my-extension --path ../local  # local development
rpi dev                                   # build + watch + live reload

Docs

• Crate docs: https://docs.rs/rpi-extensions
• Extension authoring guide
• Plugin ABI contract
• Ready-to-install extensions

License

MIT. See LICENSE and NOTICE.