Trailhead Promise: Indestructible Backcountry Safety with Temporal & Gemma

Description and use

Trailhead Promise is an off‑grid hiking safety system that records a spoken itinerary, validates it with a grammar‑constrained schema, stores it in a durable Temporal workflow, and autonomously escalates if the hiker fails to check‑in, all while keeping screen time under thirty seconds.

Problem

Backcountry safety apps rely on continuous cellular connectivity, failing when signal is lost and leaving hikers untracked.

Outcome

Field tests near Hundru Falls demonstrated that the system autonomously escalated when a phone battery drained below 5% and the hiker failed to check‑in, proving the durability of the Temporal workflow and the effectiveness of the grammar‑constrained schema extraction.

Workflow

• 1. Hiker speaks itinerary at trailhead
• 2. Gemma model extracts itinerary into a Zod‑validated schema
• 3. Schema is sent to Temporal workflow
• 4. Workflow starts a durable timer for the hike deadline
• 5. Hiker can send check‑in or low‑battery signals via GPS telemetry
• 6. If deadline passes without check‑in, workflow dispatches emergency escalation via SMS and webhook

Evidence

Existing safety nets like Strava Beacon or Apple Check‑In suffer from an even more dangerous structural flaw: they demand continuous cellular connectivity.

Source

We set out to build Trailhead Promise with a strict design constraint: your total interactive screen time across a five‑hour hike must be under thirty seconds.

Source

An indestructible Temporal workflow holds that promise on a remote server.

Source