# description
A signed, tamper-evident, independently-reproducible record that a parametric catastrophe trigger ('metric operator threshold' at a location) was MET or NOT MET against an authoritative source reading. Carries the four properties that end a parametric payout dispute: (1) a pinned + hashed methodology, (2) the exact re-fetchable source_url plus a raw_reading_hash anyone can reproduce, (3) a deterministic determination (triggered + payout_factor + rationale) re-computable by any party, (4) an Ed25519 signature (anchorable to Bitcoin via /v1/anchor). The neutral calculation-agent-of-record artifact a parametric insurer, reinsurer, regulator, or smart contract settles against. Detached Ed25519 signature over the object minus its `signature`, json-sorted-compact. SCOPE: attests what the official source reported and what the pinned methodology implies — NOT ground-truth physical loss.

# properties.peril.description
earthquake | tropical_cyclone | flood | excess_rainfall | wildfire | drought | volcanic | space_weather | weather

# properties.contract_ref.description
opaque caller/policy id — MUST NOT contain PII

# properties.trigger_definition.description
The trigger as pinned at contract inception. The methodology is frozen and hashed so nobody can move the goalposts after the event.

# properties.trigger_definition.properties.methodology.description
human-readable statement of the exact deterministic determination function

# properties.trigger_definition.properties.methodology_hash.description
sha256:<hex> of the pinned methodology — re-computable by any party

# properties.observation.description
What the authoritative source actually reported. source_url is re-fetchable by anyone; raw_reading_hash is sha256 of the exact upstream payload so a third party can confirm the reading was not altered.

# properties.observation.properties.event_id.description
the source's own event id, when applicable

# properties.observation.properties.source_url.description
exact, key-free, re-fetchable upstream URL

# properties.observation.properties.raw_reading_hash.description
sha256:<hex> of the canonical source reading (see hash_method)

# properties.observation.properties.hash_method.description
the exact, reproducible recipe to recompute raw_reading_hash from source_url

# properties.observation.properties.volatile_fields_removed.description
per-request fields stripped before hashing (e.g. generationtime_ms) so the hash is reproducible

# properties.determination.description
Deterministic result of applying the pinned methodology to the observation — re-computable by any party. Dynamic Feed executes a pre-agreed function and signs the result; it exercises no judgement.

# properties.determination.properties.payout_factor.description
0.0–1.0; binary or stepped per the pinned methodology