@raindrop-ai/pi-agent

Automatic observability for Pi Agent with Raindrop. Captures agent runs, LLM generations, tool calls, and token usage.

Two entry points:

• @raindrop-ai/pi-agent — programmatic subscriber for pi-agent-core users
• @raindrop-ai/pi-agent/extension — pi-coding-agent CLI extension (auto-discovered via pi install)

Requires Pi 0.84.4 or later and Node.js 22.19.0 or later, matching Pi's runtime requirement. This requirement applies to the Pi integration, not other Raindrop SDKs.

Quick Start — Programmatic

import { Agent } from "@earendil-works/pi-agent-core";
import { createModels } from "@earendil-works/pi-ai";
import { openaiProvider } from "@earendil-works/pi-ai/providers/openai";
import { createRaindropPiAgent } from "@raindrop-ai/pi-agent";

const raindrop = createRaindropPiAgent({
  writeKey: "your-write-key",
  userId: "user-123",
});

const models = createModels();
models.setProvider(openaiProvider());
const model = models.getModel("openai", "gpt-4o-mini");
if (!model) throw new Error("Model unavailable");

const agent = new Agent({
  streamFn: models.streamSimple,
  initialState: {
    systemPrompt: "You are a helpful assistant.",
    model,
  },
});

raindrop.subscribe(agent);
await agent.prompt("Hello!");
await raindrop.shutdown();

Quick Start — Pi Coding Agent CLI

pi install npm:@raindrop-ai/pi-agent

Set RAINDROP_WRITE_KEY in your environment. Traces appear automatically.

Projects

If your org has multiple projects, route events to a specific one by passing its slug as projectId programmatically:

const raindrop = createRaindropPiAgent({
  writeKey: "your-write-key",
  projectId: "support-prod",
});

For the CLI extension, set the slug via the RAINDROP_PROJECT_ID env var (or the project_id config-file key). Either way this sets the X-Raindrop-Project-Id header on every event. Omit it (or use "default") to use your org's default Production project — the existing behavior. Single-project orgs need nothing new.

Model context and tool results

Programmatic subscriptions capture the system prompt, messages, and tools after Pi applies transformContext. Model spans start before the provider call and include reasoning and tool calls. Tool spans preserve the full result envelope, including model-visible content and any details, for both successful and failed tools.

For agents that finish by committing a result through a tool, provide an output reader. It runs at completion and cannot interrupt the agent if it throws:

raindrop.subscribe(agent, {
  runName: "Simulate lookup",
  getOutput: () => JSON.stringify(committedResult),
});

Payload size limits

Programmatic event and span text fields default to 1,000,000 characters. Set maxTextFieldChars on createRaindropPiAgent to use a different positive limit across the subscriber and both shippers. For full capture of large replay payloads, use Number.MAX_SAFE_INTEGER; transport and ingest limits still apply. The CLI extension retains its existing event and span limits.

Oversized JSON tool payloads are pruned to fit the configured limit while staying valid JSON. A stricter OTEL_SPAN_ATTRIBUTE_VALUE_LENGTH_LIMIT can still truncate serialized JSON afterward in the shared trace shipper.

Documentation

See the full Pi Agent docs for configuration, per-subscribe overrides, and extension settings.

License

MIT

Application Git identity

Set appGit on createRaindropPiAgent to override commitSha, commitDirty, and optional ordinary branch, or pass false to opt out. For the CLI extension, use app_git in ~/.pi/agent/raindrop.json or .pi/raindrop.json, with commit_sha, commit_dirty, branch, source_directory, detect_branch, and auto_detect; app_git: false opts out. Pi may observe a coding workspace remotely, so the revision is unknown by default: ambient deploy/CI and observer working-directory metadata are ignored. Local Git discovery requires an explicit sourceDirectory / source_directory (or RAINDROP_GIT_SOURCE_DIRECTORY); explicit RAINDROP_COMMIT_SHA values are honored. Automatic branch discovery requires detectBranch: true / detect_branch: true.