load-rate-card

name	load-rate-card
description	Loads shared/rate-card.json at SessionStart, validates the schema via the rate-card-validator agent (Haiku), checks staleness, and emits warning events if the rate card is > 60 days old. Use when: a SessionStart hook fires. Do not use for computing per-call costs (see observe-call) — this skill only loads and validates the card; it does not perform cost math.
model	haiku
tools	["Read"]

load-rate-card

Preconditions

• shared/rate-card.json exists
• The file is valid JSON (if not, fire hard failure — cost attribution is impossible without a valid rate card)

Inputs

• shared/rate-card.json
• Current date (for staleness computation)

Steps

1. Read shared/rate-card.json via Python stdlib json.load.
2. Validate required top-level keys: effective_from, currency, models, modifiers, fallback_model_rate.
3. Validate per-model schema: every model entry has input_rate_per_mtok and output_rate_per_mtok, both positive floats.
4. Validate modifiers: cache_write_modifier, cache_read_modifier, batch_discount — all positive floats; cache_read_modifier < 1.0 < cache_write_modifier (cache reads should be cheaper, writes more expensive; if the relation is inverted, the card is corrupted).
5. Compute days_old = today - effective_from.
6. Emit staleness signal:
   • days_old ≤ 60: silent, no event.
   • 60 < days_old ≤ 90: emit pech.rate_card.stale.warning.
   • 90 < days_old ≤ 180: emit pech.rate_card.stale.warning + set global PECH_RATE_CARD_STALE=1 so every ledger row is tagged.
   • days_old > 180: emit pech.rate_card.stale.blocking + refuse observation (exit non-zero from observe hook — the only place a Pech hook blocks).

Success criterion: schema valid, staleness signal correct, rate-card cached in-memory for the session (written to /tmp/.pech-rate-card-<session_id>.json for hook-to-hook continuity since hooks are stateless processes).

Outputs

• /tmp/.pech-rate-card-<session_id>.json — cached rate-card for this session
• Event: pech.rate_card.refreshed (on newer-than-prior-session load), or pech.rate_card.stale.{warning,blocking} per policy

Handoff

Downstream: cost-tracker/observe-call reads the cached rate card per call; budget-watcher inherits the staleness tag.

Failure modes

Code	Scenario	Counter
F14	Soft-ignore a > 180 day stale card to keep the session running	Hard-fail; observation against dangerously stale rates is worse than no observation
F02	Fabricate missing modifier values	Reject the card; never compute cost with made-up modifiers
F08	Reach for curl/wget to fetch fresh rates	Brand invariant: zero external runtime deps; refresh happens via CI, not here