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Model Assumption Register

Document — instantiates Agentic Control Loop Design

A living list of every assumption the agent's world model rests on, each with an owner, a confidence, and a stated trigger for when it must be revisited.

The Model Assumption Register is a maintained document that makes an agent's world model auditable by writing down the beliefs it silently depends on — "customer demand is roughly stable," "the supplier ships in fourteen days," "this sensor is calibrated" — and giving each one an owner, a confidence level, and a revisit trigger: the specific observation that should force it to be re-examined. Its defining move is separating a belief from its warrant: an assumption held at 90% confidence with a clear falsifier is a different object than the same words held on habit, and the register forces that distinction onto the page. It is a standing artifact of what we currently assume and when we agreed to doubt it — not a review, and not the act of updating, but the ledger those depend on.

Example

A consumer-goods company runs a demand-forecasting model that drives factory orders. When forecasts miss, arguments go in circles because nobody can say which of the model's beliefs actually broke. The planning team builds a Model Assumption Register. Entries: "promotional lift averages 20%" (owner: marketing analyst; confidence: medium; revisit if two consecutive promotions land outside 10–30%). "Supplier lead time is 14 days" (owner: procurement; confidence: high; revisit on any shipment past 18 days). "Last year's seasonality still holds" (owner: forecasting lead; confidence: low; revisit each quarter).

The next quarter, two promotions land at 6% lift. Because that assumption carried an explicit trigger, it does not slip by as noise — the register flags it as tripped, names its owner, and routes it to be re-examined. The register did not recompute the forecast or decide the new lift number; it made one specific, previously-invisible belief the thing under review, so the model gets revised where it actually broke rather than being globally distrusted.

How it works

  • Surface the load-bearing beliefs. Walk the model and write down the assumptions its outputs actually depend on — the ones that, if wrong, would change the answer — not every incidental parameter.[n1]
  • Attach a warrant to each. For every assumption record its owner, its confidence, and the evidence it currently rests on, so a shaky belief cannot masquerade as a settled fact.
  • Write the revisit trigger. State the specific, checkable observation that should force re-examination — a threshold, a date, a contradicting result — turning "we'll revisit if things change" into a falsifier someone can actually test.
  • Keep it living, not archived. The register is edited as beliefs are added, retired, or tripped; a version frozen at project kickoff is a fossil, not a control.

Tuning parameters

  • Assumption granularity — how finely beliefs are itemized. Finer registers catch a narrow assumption that breaks alone but grow long and unread; coarser ones stay maintained but bury the specific belief that failed.
  • Confidence scheme — qualitative bands versus explicit probabilities. Numbers sharpen comparison and stress-testing but invite false precision; bands are honest about vagueness but blur which belief is really the weakest.
  • Trigger strictness — how sensitive each revisit condition is. Tight triggers re-examine beliefs early and often, at the cost of churn; loose triggers stay quiet and let a stale assumption drive decisions longer.
  • Ownership granularity — one custodian for the register versus a named owner per line. Per-line owners create real accountability for each belief but add coordination; a single custodian is simpler but diffuses who must actually check.

When it helps, and when it misleads

Its strength is converting a model's tacit commitments into explicit, ownable, falsifiable ones — so when the model fails, the argument is about which named assumption broke rather than whether the whole thing is untrustworthy. It is the artifact that lets a team update a belief surgically, and it quietly resists the confident-error failure mode by keeping each belief's warrant visible.

Its failure modes are those of any register. It goes stale: written once, admired, and never edited, it documents last year's beliefs while today's decisions run on unlisted ones. It breeds false comfort — a thorough-looking register implies the model is well-understood even as the assumption that actually matters sits unrecorded because no one thought to doubt it. And confidence labels can be theater, high numbers assigned to protect a belief rather than to describe the evidence. The guarding discipline is the living clause paired with real triggers: a register earns trust only when tripped assumptions visibly get re-examined and unlisted surprises get added.

How it implements the components

The register realizes the archetype's model-legibility slice — the belief structure behind the loop and the written rule for when it must change:

  • world_model — it externalizes the model's load-bearing assumptions into an inspectable ledger, so the actor's belief about its situation is auditable rather than tacit.
  • model_update_rule — each entry's revisit trigger is a written rule for when the model must be re-examined: the specific observation that should overturn the belief.

It records assumptions and their triggers but performs no review — applying an update from real outcomes is After-Action Learning Cycle's recurring work; the live effect_feedback_loop that would trip a trigger is Agency Health Dashboard's, and proportional_accountability_frame belongs to the after-action ritual. The register is the standing list of what we assume and when to doubt it; the cycle is the meeting that actually revises the model.

Editorial Notes

Form Classification

Form family: Record, Log & Register

Rationale: Model Assumption Register operates as a durable record, ledger, register, or trace whose value depends on preserving actual state or history because it a living list of every assumption the agent's world model rests on, each with an owner, a confidence, and a stated trigger for when it must be revisited.

Independent corroboration: The frozen evidence defines Model Assumption Register as 'A living list of every assumption the agent's world model rests on, each with an owner, a confidence, and a stated trigger for when it must be revisited', so its operative form is Record, Log & Register.

Review outcome: Independent reviewer agreement; high confidence.

Origin Attribution

Primary origin: Security Studies & Intelligence Analysis

Origin pattern: Cross-disciplinary synthesis

Present-day reach: Multi-domain

Rationale: The CIA Key Assumptions Check directly establishes the enumerate-and-revisit assumption lineage; engineering registers and organizational ownership make it standing and operational. This establishes security_intelligence as the primary origin lineage rather than merely a domain where the mechanism is now applied.

Related originating lineages:

  • Engineering & Design — Explicit assumption registers with owners and review triggers descend from systems-engineering requirements and risk practice.
  • Organizational & Management Science — Risk and project governance materially developed assumption registers with owners and review triggers.

Review resolution: Authoritative/primary-source research resolves the conflicting primary-origin claims in favor of security_intelligence: The CIA Key Assumptions Check directly establishes the enumerate-and-revisit assumption lineage; engineering registers and organizational ownership make it standing and operational. Retained alternate origins (engineering_design, organizational_management) are limited to independently formative or materially shaping lineages supported by the reviewer evidence; downstream adoption alone was not promoted to origin. The breadth of present-day use is recorded separately as domain_reach=multi_domain. origin_mode=cross_disciplinary_synthesis, confidence=medium, and encyclopedia_synthesis=true reflect the surviving provenance evidence and the encyclopedia's generalization.

Attribution caveat: The mechanism turns a one-time analytic check into a living operational register.

Encyclopedia synthesis: The exact catalogued form synthesizes established practice rather than reproducing a single standard historical label.

Review outcome: Researched adjudication after independent review; medium confidence.

Sources consulted:

Notes

The register stores the written update rule — the trigger — while the After-Action Learning Cycle is the recurring ritual that acts on a tripped trigger. Keeping the two separate is what lets a team improve its list of assumptions without turning every edit into a review meeting, and lets a review revise the model without first having to reconstruct what was assumed.

[n1] A key assumptions check is a structured-analysis technique that lists the assumptions an analytic judgment rests on and asks which would, if wrong, change the conclusion. The register operationalizes that check as a standing document with owners and revisit triggers rather than a one-time exercise.