Replaceability is strength
A monolithic system is hard to repair because every change touches the whole. A model ecology is easier to repair because each capability can be isolated behind a contract. When the summarizer fails, replace the summarizer. When the router underperforms, test a new router. When one adapter becomes stale, retire it without rebuilding the entire stack.
Replaceability also improves confidence. Teams can compare two components under identical contracts and make a narrow release decision.
Replacement checklist
| Question | Positive outcome |
|---|---|
| Does the candidate satisfy the same input/output contract? | It can substitute without interface churn. |
| Does it reduce latency or memory? | It can improve user experience immediately. |
| Does it preserve abstention and uncertainty behavior? | It remains predictable under low confidence. |
| Does it have rollback lineage? | It can be removed cleanly. |
FUNCTION replace_component(slot, candidate, ecology)
REQUIRE candidate.contract == ecology.slots[slot].contract
shadow = run_shadow(candidate, ecology.slots[slot].traffic_sample)
IF shadow.net_benefit > policy.replacement_threshold
ecology.slots[slot] = candidate
RETURN "replacement promoted"
END IF
RETURN "incumbent retained"
END FUNCTIONDesign principle
Make the system strong by making every part less sacred. A component earns its place through current evidence and can be replaced by something better.
Source reports used for this guide
These reports are preserved verbatim in the site archive. The guide above is an editorial synthesis and may narrow, qualify, or reorganize claims from the source material.