This agent guide from Thinkroom (Kieran Klaassen's platform) describes the Compounding Knowledge Lifecycle of the compound-engineering-plugin: the mechanism by which "a lesson learned once keeps paying off." The founding bet of compound engineering: each unit of work should make the next one easier. But code improves the product, not the process; what compounds is knowledge — provided it is documented in a form retrievable at the exact moment it is needed. The real bottleneck is therefore not writing (postmortems "rot in wikis") but retrieval, here made automatic across five skills rather than left to discipline.
The unit is the learning: a markdown file, one solved problem, under docs/solutions/<category>/, whose entire frontmatter serves search (title, tags, module, problem_type, applies_when, severity, date). The problem_type field splits into bug-track (what broke) and knowledge-track (what was decided/discovered) — because "a system that only retains bugs forgets the essential." Living corpus: 35 learnings, skill-design leading. Above that, the pattern doc generalizes across several learnings (more leverage, more risk if it goes stale).
Capture happens via /ce-compound, whose core discipline is timing (documenting while context is still fresh), with a subagent fan-out (analyzer, extractor, anti-duplicate) while only the orchestrator writes the single doc. The canonical example — incident #714 becoming a fix + learning + test + doctrine — shows that "compounding" means retiring failure classes, not stacking up documents.
The memory map contrasts the durable (git: docs/solutions/, CONCEPTS.md, STRATEGY.md, plans/brainstorms = the WHY) with the ephemeral (re-derivable repo-profile cache). Detection pushes nothing: five skills pull at decision time via the grep-first learnings-researcher (35 docs → frontmatter greps → candidates → full-read → 5 findings). /ce-code-review is "the sharpest tooth": a violation becomes a file:line finding. Two trust rules protect it: present evidence wins and date is signal.
Finally, refresh keeps memory from lying via three counter-forces (read time, write time via coherence neighborhood, scoped on-demand /ce-compound-refresh). The full loop is illustrated end-to-end by the delivery of /ce-explain. Financial metaphor: learning = principal, retrieval = interest, pattern doc = reinvestment — a system where new work "arrives immunized against past mistakes."