---
policy_id: trsl:policy:linear-longstop-v0@1.0
title: Linear Longstop v0
---

# Linear Longstop v0

Adopted 2026-07-29
(`workplans/TREV-WP-0007-degeneration-policy-and-canonical-profiles.md`
T02, maintainer-accepted): confirmed as the v1 norm for the first pilot
cohort, not merely a Stage 0 pilot placeholder.

## Definition

- Remission accrues **only** by time toward a declared **Longstop Date**
  (`specs/OpenQuestions-WorkingDefaults.md` Q8).
- Between Phase activation `t0` and Longstop `tL`,

  R(t) = T0 × clamp((t − t0)/(tL − t0), 0, 1)

  with discrete ledger `remission-credit` entries computed on a published
  schedule (e.g. daily or monthly UTC), **or** a single full remission at
  longstop for minimal implementations.
- Development Credit does not change the remission schedule in v0 (no
  progress-sensitive boost/pause).

## Status

Automated as of WP-0013 (`src/target_revenue/remission.py`):

- Pure cumulative formula: `cumulative_remission(T0, t0, tL, as_of)`.
- Hosted apply writes the delta
  `max(0, R(as_of) − Σ policy remission-credit already on the ledger)`.
- **t0** = Trust Service `phase_manifests.registered_at` (no separate
  `activated_at` manifest field in Stage 0).
- **Cadence**: monthly UTC (1st 00:00) for scheduled batch
  (`POST /remission/run`); on-demand via
  `POST /phases/{id}/remission` or Control Plane "Apply policy remission now".
- **Actor**: Licensor credential labeled `system:policy-engine`
  (not a human token).
- Re-runs at the same `as_of` are no-ops (idempotent by cumulative delta).

## Superseded / next iteration

`specs/TargetDegenerationPolicyResearch.md` (T01) proposes a candidate
`trsl:policy:progress-paused-longstop-v1` (a 90-day rolling "quiet
period" pause on Remission Credit during active Development Credit
periods), research complete but **not adopted**. Explicitly recommends
*not* adopting a diversity-of-payers factor (no gaming-resistant signal
exists yet). Named as the next iteration, to be revisited once real
pilot Development Credit data exists — not required before pilot Phases
proceed under v0.