Aggregation Layer
The Aggregation Layer is responsible for one architectural problem:
Transforming many independently executed shard outputs into one deterministic, reproducible, and semantically correct execution result.
Distributed computation naturally produces partial results.
Applications require one canonical result.
The Aggregation Layer exists to bridge that gap without changing the meaning of the computation itself.
Aggregation restores execution truth.
It never creates it.
The Reduction Problem
Every distributed workload produces multiple independent execution outputs.
Those outputs may originate from:
- different Agents
- different hardware
- different geographic regions
- different execution times
Despite these operational differences, the runtime must produce one canonical result whose meaning is identical to the computation originally described by the execution contract.
The architectural challenge is therefore not combining outputs.
It is preserving computation semantics while reconstructing one deterministic execution result.
Aggregation Philosophy
The Aggregation Layer performs deterministic reduction.
It never performs computation.
Primitive families define computational meaning.
Agents perform computation.
Verification evaluates execution correctness.
Aggregation reconstructs one canonical result from many valid partial outputs.
Reduction preserves meaning.
It never invents meaning.
Relationship to the Runtime
The Aggregation Layer operates after distributed execution has completed.
It receives verified shard outputs and reconstructs one canonical execution result.
Execution Contract
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Hub Coordination
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Scheduler Placement
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Agent Execution
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Verification
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Aggregation
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Execution Evidence
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Final ResultAggregation is the architectural boundary between distributed execution and canonical execution results.
Primary Responsibilities
Deterministic Reduction
Reduce distributed shard outputs into one deterministic result.
Reduction preserves:
- execution semantics
- execution ordering policies
- workload correctness
- reproducibility
Semantic Preservation
The Aggregation Layer never changes the meaning of computation.
Primitive families define semantics.
Aggregation reconstructs outputs according to those semantics.
Canonical Result Construction
Produce one canonical output regardless of:
- shard ordering
- Agent participation
- execution timing
- infrastructure diversity
Equivalent execution contracts should produce equivalent canonical results.
Artifact Assembly
Reconstruct execution artifacts produced across multiple shards.
Examples include:
- media outputs
- matrices
- datasets
- simulation outputs
- generated reports
- structured archives
Artifacts become part of the execution evidence.
Execution Evidence Completion
Aggregation contributes execution-level metadata describing how the final result was reconstructed.
Examples include:
- reduction metadata
- aggregation strategy
- reduction ordering
- participating shards
- artifact references
- canonical checksums
Execution Evidence remains incomplete until aggregation has finished.
What the Aggregation Layer Never Does
Architectural boundaries remain explicit.
The Aggregation Layer never:
- executes primitive workloads
- schedules execution
- plans execution
- modifies execution contracts
- changes primitive semantics
- performs hidden computation
- interprets business meaning
- repairs invalid shard outputs
Aggregation reconstructs valid computation.
It does not replace it.
Reduction Lifecycle
Every distributed workload follows the same reduction lifecycle.
Receive Verified Shard Outputs
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Validate Structure
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Select Reduction Strategy
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Perform Deterministic Reduction
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Construct Canonical Result
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Complete Execution Evidence
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Return Final ResultReduction strategies differ.
The reduction lifecycle does not.
Reduction Strategies
Different primitive families require different deterministic reduction strategies.
Statistical Reduction
Examples include:
- Monte Carlo simulations
- probabilistic models
- risk analysis
Typical operations include:
- accumulation
- variance reconstruction
- quantile estimation
- probability normalization
Numerical Reduction
Examples include:
- matrix multiplication
- linear algebra
- numerical optimization
Typical operations include:
- tile reconstruction
- deterministic floating-point ordering
- boundary correction
Ensemble Reduction
Examples include:
- climate simulation
- scenario analysis
- distributed forecasting
Typical operations include:
- ensemble averaging
- anomaly reconstruction
- coefficient recombination
Media Reconstruction
Examples include:
- video processing
- audio processing
- image pipelines
Typical operations include:
- segment concatenation
- timestamp validation
- codec consistency
- artifact assembly
Primitive families define which reduction strategy applies.
The Aggregation Layer executes that strategy.
Deterministic Reduction
Deterministic aggregation depends on explicit reduction discipline.
Examples include:
- stable reduction ordering
- deterministic floating-point policy
- canonical reduction algorithms
- explicit primitive versions
- profile version discipline
- invariant output schemas
Reduction correctness depends on preserving semantics rather than maximizing execution speed.
Relationship to Verification
Aggregation follows verification.
Verification determines whether execution outputs satisfy execution policy.
Aggregation assumes verified inputs.
Verification increases confidence.
Aggregation reconstructs canonical truth.
These responsibilities remain intentionally separate.
Contribution to Execution Evidence
The Aggregation Layer contributes canonical reconstruction metadata.
Examples include:
- reduction strategy
- participating shards
- reduction ordering
- aggregation timestamps
- canonical checksums
- artifact references
- reconstruction metrics
This information enables replay, inspection, verification, and audit.
Failure Model
Aggregation assumes incomplete and imperfect distributed execution.
Examples include:
- missing shard outputs
- duplicated shard outputs
- verification rejection
- numerical drift
- artifact corruption
- timeout
- interrupted reconstruction
Failures affect result availability.
They must not compromise execution correctness.
Runtime Observability
The Aggregation Layer continuously emits operational metadata.
Examples include:
- reduction progress
- participating shards
- reconstruction timing
- reduction latency
- artifact generation
- reconstruction failures
- aggregation duration
These signals make canonical reconstruction observable.
Architectural Guarantees
The Aggregation Layer is designed to preserve:
- deterministic reduction
- semantic preservation
- canonical result construction
- replayable aggregation metadata
- explicit reduction strategies
- observable reconstruction
- heterogeneous execution compatibility
These guarantees define canonical reduction independently of workload type.
Architectural Non-Goals
The Aggregation Layer intentionally does not:
- execute workloads
- define computation semantics
- modify execution contracts
- replace verification
- schedule execution
- interpret business meaning
- repair incorrect computation
Its responsibility begins with verified shard outputs.
Its responsibility ends with one canonical execution result.
How to Verify Aggregation Behavior
A technical evaluator can inspect one distributed execution.
Suggested verification path:
- Execute a workload spanning multiple shards.
- Inspect individual shard outputs.
- Review verification outcomes.
- Observe aggregation strategy.
- Inspect reduction metadata.
- Compare reconstructed outputs with execution evidence.
- Replay the aggregation process where supported.
The observed reconstruction should correspond to the lifecycle described in this document.
Related Documentation
Continue with:
- Storage Architecture
- Transport Architecture
- Scaling Architecture
- Execution Path
- Agent Kernel Architecture
Final Mental Model
The Aggregation Layer is where many independent computations become one canonical execution result.
Agents produce computation.
Aggregation restores coherence.
The meaning of the computation never changes.
Only its distributed form does.
