Dependency record template
Dependents, substitution cost, expertise retained, alternatives, and exposure score.
MEC-18 Dependency ledger
Track who now depends on the system, what substitution would cost, which expertise remains, and which capacities are being preserved to keep withdrawal possible.
Permanent link /mechanisms/patterns/dependency-ledger
Where it fits
Filters and handoffs
Tagged for Governance, Policy with validator handshakes. Includes 3 steps, 3 reusable assets, and 4 snippet blocks.
Copy citation (APA/BibTeX)
Cite this page Formats: APA, MLA, Chicago, BibTeX, RIS
APA
Ethotechnics Institute Research Team. (2026). MEC-18 Dependency ledger. Ethotechnics Institute. https://ethotechnics.org/mechanisms/patterns/dependency-ledger
MLA
Ethotechnics Institute Research Team. "MEC-18 Dependency ledger." Ethotechnics Institute, 2026, https://ethotechnics.org/mechanisms/patterns/dependency-ledger.
Chicago
Ethotechnics Institute Research Team. "MEC-18 Dependency ledger." Ethotechnics Institute. Jan 9, 2026. https://ethotechnics.org/mechanisms/patterns/dependency-ledger.
BibTeX
@misc{mechanism_dependency-ledger,
title={MEC-18 Dependency ledger},
author={Ethotechnics Institute Research Team},
year={2026},
howpublished={Ethotechnics Institute},
url={https://ethotechnics.org/mechanisms/patterns/dependency-ledger},
version={v1.1.0}
}
RIS
TY - WEB TI - MEC-18 Dependency ledger AU - Ethotechnics Institute Research Team PY - 2026 UR - https://ethotechnics.org/mechanisms/patterns/dependency-ledger ER -
Specification overview
At-a-glance details for planning and handoffs.
Capture the scope, assets, and validator handshakes before diving into the steps.
Spec essentials
What ships with this mechanism
- 3 steps with checklist-ready owners.
- 3 reusable assets for briefs and runbooks.
- 4 reuse-ready snippet blocks.
- 3 glossary anchors for shared terms.
Filters & validators
Where this spec sits in the system
Tagged in 2 filters with 2 linked validators.
Glossary anchors
Link back to the definitions.
Jump to the glossary terms that frame this mechanism.
Steps
Put the mechanism in motion.
Start with the field cues, then use the assets to keep the work legible.
3 steps with checklist-ready owners, plus linked assets for handoffs.
0 of 3 steps complete
Assets
Keep outputs reusable.
Link or copy these assets into design docs, runbooks, and briefs so the mechanism travels with the work.
Exposure score worksheet
How depth of dependence, substitution cost, and correction latency combine into the score.
Preserved capacity register
Capacities kept alive for withdrawal, with owners, budget, and review dates.
Reuse-ready snippets
Copy policy, audit, and incident language.
Use these snippets in requirements, audits, and postmortems with the mechanism permalink.
Policy requirement
Policy requirement (MEC-18 Dependency ledger) - Maintain a dependency ledger with dependents, substitution cost, expertise retained, alternatives, and an exposure score. - Name the capacities preserved to keep withdrawal possible, each with an owner. Reference: https://ethotechnics.org/mechanisms/patterns/dependency-ledger
Product requirement
Product requirement (MEC-18) - Exposure score and its inputs are reported alongside reliability metrics. - Changes in dependents or alternatives update the ledger within the review cycle.
Audit evidence checklist
Audit evidence checklist (MEC-18) [ ] Dependents are listed with the consequence of an outage for each. [ ] Substitution cost, expertise retained, and alternatives are recorded and dated. [ ] Preserved capacities have owners and evidence they are still funded.
Postmortem trigger
Postmortem trigger (MEC-18) Trigger review when exposure rises materially without a corresponding change in preserved capacity.
Example usage
Ledger for a scheduling system three years in
A concrete scenario to help teams see how the pieces fit together.
How it plays out
A hospital records that two departments have retired their manual rota, that the last two schedulers who could rebuild it retire next year, and funds a documented fallback rota as a preserved capacity.
Anti-patterns
Common failure cases and counterfactuals
Use these to avoid superficial compliance and clarify what success requires.
Reliability as safety
High uptime is read as low risk, while the institution's ability to work without the system quietly disappears.
Counterfactual: Dependence is tracked separately from reliability, with its own score and owners.
False-positive warning: A reliable system can be a safe one; the ledger asks a different question, which is what happens when it is gone.
Ledger without alternatives
Dependents are recorded but substitutes are never checked, so the entry cannot show when the last alternative disappeared.
Counterfactual: Alternatives are re-checked on the review cadence and dated.
False-positive warning: Having no alternative is a legitimate finding as long as it is recorded as one.
Validators
Pair validators with this mechanism.
Use these tools to size risk and keep the stewardship path visible.
Validator
Technical Capacity Forecaster
Charts compound decay against refusal windows to spot saturation risk across a 24-month horizon.
Validator
Maintenance Debt Calculator
Maps decision speed, intervention readiness, and revenue exposure to quantify maintenance debt risk.