Coast Range TMC

Three independent conjuncts must resolve — TOM prose, FIRMS pixels, NASADEM elevation — before a postmile flips or a Reopen succeeds.

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About the project

Overnight, a coastal TMC is dark. The analog already closed Highway 1 where crews could see the fire. What they cannot do, postmile by postmile, while the desk is empty, is ask: is a satellite footprint still sitting on the slope above this traveled way — and if so, may anyone reopen it?

Upslope is that leftover job. It is a fixture desk named Coast Range TMC (D5-shaped SHN clip). Not Caltrans. Not a chatbot. Not a wildfire map. If you strip the map, the product that remains is a Firestore TMCAL row (OPEN → CLOSED_FIRE) and a product URL that refuses reopen while FIRMS is still upslope.

Inspiration

Highway-condition duty is conjunction, not vibe. Traffic Operations Manual Chapter 110 already says the hard parts in prose: report county, route, and post mile; HCRR within 10 minutes of a full/directional closure; close when the roadway is not passable. PIO language for this corridor talks about falling rock from the steep slope above the highway. NASA already detected the heat. The overnight dispatcher does not need another map. They need a write that survives first shift, and a reopen that cannot be rubber-stamped while the slope is still hot.

The occupied work is “there is a fire, close Hwy 1.” The unoccupied slice is: this postmile is still CLOSED_FIRE; POST /reopen/CA-1/PM12 is REFUSED, with the three quotes still attached (acq_time, SHN span, $z_\Delta$).

How we built it

The overnight wake is an event-driven ADK workflow, not a chat loop:

  1. Gun. GET NOAA FIRMS 24h CSV + KML (no MAP_KEY). Live gun is that feed — not the Earth Engine FIRMS catalog (one-day lag). Frozen A/B replay against live SHN bytes; the Live pane GETs this morning’s CSV every time it opens. Honest empty is allowed.
  2. Quotes, never MATCH. A Gemini 3.7 Flash LlmAgent (Vertex AI, GOOGLE_CLOUD_LOCATION=global) orchestrates FunctionTools. A nested quote clerk (AgentTool) returns verbatim TOM / FIRMS strings — or CAN'T READ. On 429 we shed to Gemini 3.5 Flash. Same tools. MATCH still cannot come from the model.
  3. Stdlib conjunction. Python decides MATCH. Gemini’s output is never eval’d.

$$ \text{MATCH} = C_{{\text{nominal},\text{high}}} \;\land\; \operatorname{ST_Intersects}(F,S) \;\land\; (z_{\text{hotspot}} > z_{\text{SHN}}) \;\land\; R \in D5 $$

Native geometry is the VIIRS pixel from CSV scan × track (~375 m). We do not invent a 100-ft buffer. BigQuery owns intersect; Earth Engine NASADEM owns upslope. Delete either engine → CAN'T READ, not MATCH. County-only (Monterey → close Hwy 1) must fail (test_county_only_must_fail).

  1. Write. Firestore TMCAL mutation + HCRR draft row (write_happened: true) + Pub/Sub witness. /conformance scores 3/3 against Firestore objects, not against Gemini prose.
  2. Reopen-gate. POST /reopen/{route}/{pm} is a product URL, not a /judges toy. Frozen A span (honest PM12) → REFUSED + three quotes. PM47 after Frozen A → ALLOWED (proves we are not a county webhook). ?format=cert returns a refusal certificate (manifest hash, outcome hash, quotes).
  3. Unreachable on purpose. Traveler-info, CAD, email, cone, blast: 404. Tool schema does not contain them.

Host is 2nd gen Cloud Functions (cloudfunctions.net). We do not advertise Cloud Run / .run.app. Model Armor is fail-closed and regional (us-central1); Gemini routing stays global. Credentials live in Secret Manager / ADC — no user-managed JSON keys in git.

Judge surfaces: /judges (Frozen A / Frozen B / Live / 404 / conformance), /health (eight enablement letters + eligibility), /reopen/..., /conformance, /llms.txt.

What we learned

  • Quote ≠ decide. If MATCH can be parsed out of an LLM string, the architecture is already a cheat. ADK is the overnight clerk; BigQuery + Earth Engine + stdlib are the closer.
  • Occupancy is a scoring kill. “AI wildfire map” and “county webhook” look demo-friendly and score as U7. The product is the refused reopen.
  • Fail closed, print the letter. Earth Engine down → no MATCH (do not close on intersect-only). Armor down → print A8; do not silently skip. Gemini older than 3.5 on the overnight/quote path is a DQ, not a fallback.
  • Dense live field beats sparse luck. Frozen A proves currently-on-fire; Frozen B proves inland pixels are not the traveled way; Live proves the gun is this morning’s CSV.

Challenges

Vertex gemini-3.7-flash 429s under ADK tool loops. The honest fix is a 3.5 Flash shed on the same FunctionTools, then a deterministic tool pipeline — never a cheaper model inventing MATCH.

Earth Engine registration is hour-0, not polish: without NASADEM the upslope conjunct cannot run, and the U7 county-closer temptation appears. We enable EE first (scripts/hour0_enable.ps1) and keep a named test that fails the build if county-only ships.

FIRMS KML is Point placemarks. Using those points plus an invented buffer would be a kill-if. CSV scan×track is the native pixel; that is the geometry BQ intersects.

The UI temptation is a map. The desk is dark #0b0b0c, typography-as-state, three-quote card, conjunction strip, write log — zero chat. A map, if it exists, is a receipt.

Built With

  • bigquery
  • cloud-functions-(2nd-gen-http)
  • cloudfunctions
  • cloudscheduler
  • cloudstorage
  • flask
  • gemini
  • genai-sdk
  • google-cloud
  • google-pub/sub
  • googleadk
  • googleearthengine
  • modelarmor
  • nasadem
  • pydantic
  • python
  • python3.11+
  • secretmanager
  • tom-ch-110-(caltrans)
  • vertex-ai
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