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Plugin Runtime Helpers

Reference for the api.runtime object injected into every plugin during registration. Use these helpers instead of importing host internals directly.
Looking for a walkthrough? See Channel Plugins or Provider Plugins for step-by-step guides that show these helpers in context.
register(api) {
  const runtime = api.runtime;
}

Runtime namespaces

api.runtime.agent

Agent identity, directories, and session management.
// Resolve the agent's working directory
const agentDir = api.runtime.agent.resolveAgentDir(cfg);

// Resolve agent workspace
const workspaceDir = api.runtime.agent.resolveAgentWorkspaceDir(cfg);

// Get agent identity
const identity = api.runtime.agent.resolveAgentIdentity(cfg);

// Get default thinking level
const thinking = api.runtime.agent.resolveThinkingDefault(cfg, provider, model);

// Get agent timeout
const timeoutMs = api.runtime.agent.resolveAgentTimeoutMs(cfg);

// Ensure workspace exists
await api.runtime.agent.ensureAgentWorkspace(cfg);

// Run an embedded Pi agent
const agentDir = api.runtime.agent.resolveAgentDir(cfg);
const result = await api.runtime.agent.runEmbeddedPiAgent({
  sessionId: "my-plugin:task-1",
  runId: crypto.randomUUID(),
  sessionFile: path.join(agentDir, "sessions", "my-plugin-task-1.jsonl"),
  workspaceDir: api.runtime.agent.resolveAgentWorkspaceDir(cfg),
  prompt: "Summarize the latest changes",
  timeoutMs: api.runtime.agent.resolveAgentTimeoutMs(cfg),
});
Session store helpers are under api.runtime.agent.session:
const storePath = api.runtime.agent.session.resolveStorePath(cfg);
const store = api.runtime.agent.session.loadSessionStore(cfg);
await api.runtime.agent.session.saveSessionStore(cfg, store);
const filePath = api.runtime.agent.session.resolveSessionFilePath(cfg, sessionId);

api.runtime.agent.defaults

Default model and provider constants:
const model = api.runtime.agent.defaults.model; // e.g. "anthropic/claude-sonnet-4-6"
const provider = api.runtime.agent.defaults.provider; // e.g. "anthropic"

api.runtime.subagent

Launch and manage background subagent runs.
// Start a subagent run
const { runId } = await api.runtime.subagent.run({
  sessionKey: "agent:main:subagent:search-helper",
  message: "Expand this query into focused follow-up searches.",
  provider: "openai", // optional override
  model: "gpt-4.1-mini", // optional override
  deliver: false,
});

// Wait for completion
const result = await api.runtime.subagent.waitForRun({ runId, timeoutMs: 30000 });

// Read session messages
const { messages } = await api.runtime.subagent.getSessionMessages({
  sessionKey: "agent:main:subagent:search-helper",
  limit: 10,
});

// Delete a session
await api.runtime.subagent.deleteSession({
  sessionKey: "agent:main:subagent:search-helper",
});
Model overrides (provider/model) require operator opt-in via plugins.entries.<id>.subagent.allowModelOverride: true in config. Untrusted plugins can still run subagents, but override requests are rejected.

api.runtime.tts

Text-to-speech synthesis.
// Standard TTS
const clip = await api.runtime.tts.textToSpeech({
  text: "Hello from FluffBuzz",
  cfg: api.config,
});

// Telephony-optimized TTS
const telephonyClip = await api.runtime.tts.textToSpeechTelephony({
  text: "Hello from FluffBuzz",
  cfg: api.config,
});

// List available voices
const voices = await api.runtime.tts.listVoices({
  provider: "elevenlabs",
  cfg: api.config,
});
Uses core messages.tts configuration and provider selection. Returns PCM audio buffer + sample rate.

api.runtime.mediaUnderstanding

Image, audio, and video analysis.
// Describe an image
const image = await api.runtime.mediaUnderstanding.describeImageFile({
  filePath: "/tmp/inbound-photo.jpg",
  cfg: api.config,
  agentDir: "/tmp/agent",
});

// Transcribe audio
const { text } = await api.runtime.mediaUnderstanding.transcribeAudioFile({
  filePath: "/tmp/inbound-audio.ogg",
  cfg: api.config,
  mime: "audio/ogg", // optional, for when MIME cannot be inferred
});

// Describe a video
const video = await api.runtime.mediaUnderstanding.describeVideoFile({
  filePath: "/tmp/inbound-video.mp4",
  cfg: api.config,
});

// Generic file analysis
const result = await api.runtime.mediaUnderstanding.runFile({
  filePath: "/tmp/inbound-file.pdf",
  cfg: api.config,
});
Returns { text: undefined } when no output is produced (e.g. skipped input).
api.runtime.stt.transcribeAudioFile(...) remains as a compatibility alias for api.runtime.mediaUnderstanding.transcribeAudioFile(...).

api.runtime.imageGeneration

Image generation.
const result = await api.runtime.imageGeneration.generate({
  prompt: "A robot painting a sunset",
  cfg: api.config,
});

const providers = api.runtime.imageGeneration.listProviders({ cfg: api.config });

api.runtime.webSearch

Web search.
const providers = api.runtime.webSearch.listProviders({ config: api.config });

const result = await api.runtime.webSearch.search({
  config: api.config,
  args: { query: "FluffBuzz plugin SDK", count: 5 },
});

api.runtime.media

Low-level media utilities.
const webMedia = await api.runtime.media.loadWebMedia(url);
const mime = await api.runtime.media.detectMime(buffer);
const kind = api.runtime.media.mediaKindFromMime("image/jpeg"); // "image"
const isVoice = api.runtime.media.isVoiceCompatibleAudio(filePath);
const metadata = await api.runtime.media.getImageMetadata(filePath);
const resized = await api.runtime.media.resizeToJpeg(buffer, { maxWidth: 800 });

api.runtime.config

Config load and write.
const cfg = await api.runtime.config.loadConfig();
await api.runtime.config.writeConfigFile(cfg);

api.runtime.system

System-level utilities.
await api.runtime.system.enqueueSystemEvent(event);
api.runtime.system.requestHeartbeatNow();
const output = await api.runtime.system.runCommandWithTimeout(cmd, args, opts);
const hint = api.runtime.system.formatNativeDependencyHint(pkg);

api.runtime.events

Event subscriptions.
api.runtime.events.onAgentEvent((event) => {
  /* ... */
});
api.runtime.events.onSessionTranscriptUpdate((update) => {
  /* ... */
});

api.runtime.logging

Logging.
const verbose = api.runtime.logging.shouldLogVerbose();
const childLogger = api.runtime.logging.getChildLogger({ plugin: "my-plugin" }, { level: "debug" });

api.runtime.modelAuth

Model and provider auth resolution.
const auth = await api.runtime.modelAuth.getApiKeyForModel({ model, cfg });
const providerAuth = await api.runtime.modelAuth.resolveApiKeyForProvider({
  provider: "openai",
  cfg,
});

api.runtime.state

State directory resolution.
const stateDir = api.runtime.state.resolveStateDir();

api.runtime.tools

Memory tool factories and CLI.
const getTool = api.runtime.tools.createMemoryGetTool(/* ... */);
const searchTool = api.runtime.tools.createMemorySearchTool(/* ... */);
api.runtime.tools.registerMemoryCli(/* ... */);

api.runtime.channel

Channel-specific runtime helpers (available when a channel plugin is loaded).

Storing runtime references

Use createPluginRuntimeStore to store the runtime reference for use outside the register callback:
import { createPluginRuntimeStore } from "fluffbuzz/plugin-sdk/runtime-store";
import type { PluginRuntime } from "fluffbuzz/plugin-sdk/runtime-store";

const store = createPluginRuntimeStore<PluginRuntime>("my-plugin runtime not initialized");

// In your entry point
export default defineChannelPluginEntry({
  id: "my-plugin",
  name: "My Plugin",
  description: "Example",
  plugin: myPlugin,
  setRuntime: store.setRuntime,
});

// In other files
export function getRuntime() {
  return store.getRuntime(); // throws if not initialized
}

export function tryGetRuntime() {
  return store.tryGetRuntime(); // returns null if not initialized
}

Other top-level api fields

Beyond api.runtime, the API object also provides:
FieldTypeDescription
api.idstringPlugin id
api.namestringPlugin display name
api.configFluffBuzzConfigCurrent config snapshot
api.pluginConfigRecord<string, unknown>Plugin-specific config from plugins.entries.<id>.config
api.loggerPluginLoggerScoped logger (debug, info, warn, error)
api.registrationModePluginRegistrationMode"full", "setup-only", or "setup-runtime"
api.resolvePath(input)(string) => stringResolve a path relative to the plugin root