Structs Streaming

Raid Alert Tool (example pattern)

A tool that watches for raids on your planet and outputs an alert:

import { connect } from "nats.ws";

const PLANET_ID = process.argv[2]; // e.g. "2-1"
const nc = await connect({ servers: "ws://crew.oh.energy:1443" });
const sub = nc.subscribe(`structs.planet.${PLANET_ID}`);

for await (const msg of sub) {
  const event = JSON.parse(new TextDecoder().decode(msg.data));
  if (event.category === "raid_status") {
    console.log(JSON.stringify({ alert: "RAID", planet: PLANET_ID, data: event }));
  }
  if (event.category === "fleet_arrive") {
    console.log(JSON.stringify({ alert: "FLEET_ARRIVAL", planet: PLANET_ID, data: event }));
  }
}

Player Creation Watcher (example pattern)

Instead of polling structsd query structs address after guild signup, watch for the address registration event:

import { connect } from "nats.ws";

const nc = await connect({ servers: "ws://crew.oh.energy:1443" });
const sub = nc.subscribe("structs.address.register.*");

for await (const msg of sub) {
  const event = JSON.parse(new TextDecoder().decode(msg.data));
  console.log(JSON.stringify(event));
  break; // exit after first match
}
await nc.close();

When to Build a Custom Tool

Build a GRASS listener tool when:

• You need to wait for an event — guild signup completion, fleet arrival, raid detection
• You need continuous monitoring — threat detection during vulnerable ore window, combat tracking
• You want an event-driven game loop — react to block events instead of polling on a timer
• You're managing multiple players — one GRASS connection can monitor all your entities simultaneously

Store custom tools in your workspace (e.g., scripts/ or alongside the relevant skill).

Connection Best Practices

• Use specific subjects once you know what you need. Wildcards are for discovery.
• Limit to 10-20 subscriptions per connection to avoid overwhelming the client.
• Implement reconnection with exponential backoff — NATS connections can drop.
• Parse JSON defensively — not all messages may match expected schema.
• Close connections when done. Don't leave idle GRASS connections open.

Procedure

Quick Setup

1. Get the GRASS endpoint from your guild config (or use ws://crew.oh.energy:1443)
2. Record the endpoint in TOOLS.md under Servers
3. Choose your language (Node.js or Python)
4. Install the NATS client library (nats.ws for Node, nats-py for Python)
5. Write a listener script for your specific use case
6. Run it in a background terminal

For Ongoing Monitoring

1. Subscribe to your planet(s): structs.planet.{id} — raid alerts, fleet arrivals
2. Subscribe to your structs: structs.struct.{id} — attack/status alerts
3. Subscribe to global: structs.global — block tick for game loop timing
4. Log events to memory/ for cross-session awareness

Automation Patterns (Defence Contractor)

The Structs permission system and GRASS event stream were designed for AI agents to automate game responses. The design docs call this the "Defence Contractor" pattern — an agent that monitors events and acts on behalf of players within scoped permissions.

Common Automation Triggers

Permission Scoping for Automated Agents

When delegating actions to an automation agent (separate key or service):

1. Grant minimal permissions: Use permission-grant-on-object to allow specific actions on specific structs, not blanket access.
2. Separate keys: The automation agent should use its own signing key, registered as a secondary address on the player via address-register.
3. Scope by struct: Grant mine/refine permissions on extractors and refineries only. Grant defense permissions on fleet structs only.
4. Revoke when not needed: Use permission-revoke-on-object to remove automation access during sensitive operations.

Example: Refine-on-Mine-Complete Loop

Subscribe to: structs.struct.{extractor-id}
On event: struct_ore_mine_complete
  → Run: structsd tx structs struct-ore-refine-compute -D 1 --from [key] --gas auto -y -- [refinery-id]

Subscribe to: structs.struct.{refinery-id}
On event: struct_ore_refine_complete
  → Run: structsd tx structs struct-ore-mine-compute -D 1 --from [key] --gas auto -y -- [extractor-id]

This creates a continuous mine-refine loop that runs unattended. Ore is never left unrefined.

Example: Defend-on-Raid-Detected

Subscribe to: structs.planet.{planet-id}
On event: planet_raid_start
  → Activate stealth on vulnerable structs
  → Set defenders on high-value structs
  → Log raid to memory/intel/threats.md
  → Alert commander if available

Safe Boundaries

• Never auto-spend Alpha without commander approval (infusion, guild-bank operations)
• Never auto-move fleets away from defended planets without threat assessment
• Always log actions to memory/ for cross-session audit trail
• Rate-limit reactions — one transaction per ~6 seconds per key (sequence number constraint)

See Also

• protocols/streaming — Full GRASS/NATS protocol specification
• api/streaming/event-types — Complete event type catalog
• api/streaming/event-schemas — JSON schema definitions for event payloads
• api/streaming/subscription-patterns — Subscription patterns and examples
• awareness/async-operations — Background operations and pipeline strategy
• awareness/threat-detection — Using GRASS for early warning