# AC6 measured composition work packet v1

- Date: 2026-08-12
- Status: implementation candidate; not a supported product or general-benefit claim
- Exact AC5 source head: `f8b3ea3ab764d0630ad6e4b0649f566893cba484`
- Stack base: `codex/v0.7-agent-delivery-export-interoperability`

## Outcome and boundary

AC6 adds a provider-neutral evaluation layer that can determine whether dynamic composition clears
one frozen materiality rule under an exact matched condition. It measures existing AC1–AC5 plans,
manifests, run receipts, authority resolutions, lifecycle outputs, and denial/replay evidence through
opaque content-addressed coordinates. It does not select or execute a participant.

Evaluation is not self-modifying intelligence. An evaluation does not become Agent Memory, update a
model, train a selector, rewrite a policy, activate a roster, grant authority, schedule work, deliver,
export, or send an external effect. A proposal is immutable and inert. Even an accepted proposal is
review evidence only until a separate present-tense approval, admission, and governed policy-head
commit are implemented and authorized outside this packet.

## Frozen preregistration

The protocol is persisted under current `evaluate_agent_composition` authority before assignment or
observation. It freezes:

- exact task, evidence, and context artifact coordinates;
- admissible output contract families;
- evidence closure and material participant-output-use criteria;
- fixed minimal, fixed multi-participant, and dynamic conditions;
- provider, model, version, randomness seed, time assumption, authority scope, destination policy,
  and one common absolute budget;
- the complete failure and degraded-state taxonomy; and
- exact evidence-closure, observed-outcome, material-use, latency, model/tool-call, token, and cost
  thresholds.

The provider-free registration uses no model and records `model:none` explicitly. A real-model run is
optional, must use an existing supported harness and credentials, and cannot become the acceptance
authority.

## Matching and causal claim rule

Each condition assignment copies the exact frozen task/evidence/context and held constants. Each
observation binds one exact invocation, run receipts, present-tense authority resolutions, output
artifacts, citation closure, participant-output material-use links, metrics, failures, and every
environmental deviation.

The deterministic evaluator compares the dynamic treatment to the strongest fixed control. It emits
`dynamic_materially_helps` only when all three observations are paired and controlled, the dynamic
run is valid, the evidence-closure gain and material-use minimum pass, a legitimately observed
outcome clears its threshold, absolute and incremental budgets pass, required usage/cost telemetry is
complete, and no fail-closed deviation remains. Unpaired, uncontrolled, stale-authority, incomplete,
or telemetry-incomplete evidence is `unproven_fail_closed`; it never supports a causal claim.

The claim is narrow: the deterministic fixture establishes that the evaluator recognizes one frozen
case in which dynamic composition meets the preregistered rule. It does not establish that dynamic
composition is generally better or that the fixture predicts human or operational benefit.

## Immutable artifact chain

The append-only service emits and exact-loads these content-addressed artifacts:

1. `ace.application.composition-evaluation-authority-resolution/v1alpha1`;
2. `ace.intelligence.composition-evaluation-protocol/v1alpha1`;
3. `ace.intelligence.composition-condition-assignment/v1alpha1`;
4. `ace.intelligence.composition-run-observation/v1alpha1`;
5. `ace.intelligence.composition-matched-comparison/v1alpha1`; and
6. optionally, `ace.intelligence.composition-policy-change-proposal/v1alpha1`.

Preregistration is atomic with its authority evidence. Every later append carries the protocol's
exact governed-head preconditions. Rotation or revocation therefore fails before the append. Stable
transaction keys, exact record identities, and exact replay validation make fresh-service closure
deterministic without duplicating an effect.

## Proposal governance

The policy proposal fixes all effect-bearing flags to false and both governance gates to true. It
binds the exact protocol, comparison, current policy, proposed rule, scope, and rollback coordinate.
The separate proposal-disposition contract supports accept-for-separate-admission, reject,
supersede, and rollback while fixing `applies_change=false`. Adoption remains a later present-tense
governed-state path; AC6 exposes no policy mutation service.

## Provider-free cases

The frozen fixture covers:

- solo suffices;
- dynamic clears the exact preregistered rule;
- dynamic adds cost with no material gain;
- missing participant, timeout, abstention, partial join, and tainted join;
- stale, revoked, and rotated authority;
- delivery and external-effect denial;
- unavailable usage and cost telemetry;
- restart and exact replay;
- attempted policy self-activation; and
- retry reconciliation with duplicate-effect prevention.

Every case runs fixed minimal, fixed multi-participant, and dynamic conditions over the same exact
coordinates. The fixture has no credential, provider SDK, network, Domain Pack, or AM1 dependency.

## Stack and public-surface preservation

Historical `DomainActivationCommitReferenceV1Alpha2` is rejected as evaluation authority and remains
lineage with `live_authority=false`. AC4 activation or compatibility-replacement evidence cannot
carry authority forward. AC5 prepared delivery, delivery receipts, and portability receipts cannot
authorize evaluation or external effects. Current heads and runtime authority remain mandatory.

AC6 adds no schema, TaskCreate field, endpoint, CLI command, public MCP tool, provider dependency,
external-repository edit, or domain vocabulary. The package remains `ace-core`; the naked kernel and
the exactly eleven thin public MCP tools are unchanged.

## AC7 entry gate

AC7 may begin only after the control tower separately authorizes a present-tense composition-policy
admission path and freezes its authority, concurrency, rollback, and operator-review semantics. The
entry packet must identify production durable owners for evaluation authority/configuration heads,
define how accepted/rejected/superseded/rollback dispositions map to a compare-and-swap policy-head
commit, preserve inert proposals and rejected history, prove no automatic activation, and retain the
same provider-free matched acceptance gate. No AC7 work may treat this fixture's positive case as a
general dynamic-composition benefit claim.
