Decay Parameters¶

Every repo carries its own memory/decay-policy.md — tunable windows and triggers for its evolving-memory layer. All windows are in sessions, not days. Integers only — count session files, never compute a score. The rules that consume them live in DECAY.md / REVIEW.md.

The full policy¶

# Lifecycle windows (sessions)
working_window:   3
active_window:    8
archive_window:   20

# Review triggers
review_every:          10
continuity_max_facts:  30   # primary lean signal
continuity_max_lines:  600  # coarse backstop

# Invariant verification
verify_invariants_every: 40

# Auto-core (default: off — core is human-set)
enabled:          false
core_min_uses:    12
core_min_reviews: 5

# Never decays
# - tier: core
# - anything under "## Architectural Invariants"
# - unchecked Open Threads ( - [ ] )

Reference¶

Parameter	Default	Meaning
`working_window`	`3`	`sessions_since_last_used` ≤ this → `working`
`active_window`	`8`	≤ this (and past `working`) → `active`
`archive_window`	`20`	≤ this (and past `active`) → `archive-candidate`; past it → archive
`review_every`	`10`	Run a review at least every N sessions; drives `[review-overdue]`
`continuity_max_facts`	`30`	Decaying facts/threads before `[continuity-bloat]` advises a review
`continuity_max_lines`	`600`	Coarse size backstop on `continuity.md`
`verify_invariants_every`	`40`	Sessions between human re-confirmations of `core` / invariants
`enabled` (auto-core)	`false`	Whether usage can auto-promote a fact to `core` (off by default — core is human-set)
`core_min_uses`	`12`	Auto-core threshold (only if `enabled`)
`core_min_reviews`	`5`	Auto-core threshold (only if `enabled`)

Tuning advice¶

continuity_max_facts is the primary signal. A count of decaying facts is immune to verbosity and velocity, unlike a line count. Tune this first.
continuity_max_lines is a coarse backstop. It was raised 300 → 600 in v4.24.0 because a healthy mature layer already sits ~450–600 lines (structural sections — Vision, Invariants, Key Decisions, Blueprint — don't decay but do count toward lines). Set too low and it's permanently red (alert fatigue).
verify_invariants_every was raised 20 → 40 to avoid near-daily human re-confirms at burst velocity (10–20 sessions/day).
The lifecycle windows (working / active / archive) and review_every rarely need changing — the common bloat cause was reviews not running, not the windows being wrong. The [review-overdue] advisory exists precisely for that.

Make changes a review, not a guess

After editing the policy, run memory-lint and a review so the new thresholds are applied consistently.