Chapter 8: Task Decomposition Strategies

8.1 Fixed Pipelines (Prompt Chaining)

Each step is defined in advance:

Document -> Metadata extraction -> Data extraction -> Validation -> Enrichment -> Final output

When to use:

• The task structure is predictable (reviews always follow the same template)
• All steps are known up front
• You need stability and reproducibility

8.2 Dynamic Adaptive Decomposition

Subtasks are generated based on intermediate results:

1. "Add tests for a legacy codebase"
2. -> First: map the structure (Glob, Grep)
3. -> Found: 3 modules with no tests, 2 with partial coverage
4. -> Prioritize: start with the payments module (high risk)
5. -> During work: discovered a dependency on an external API
6. -> Adapt: add a mock for the external API before writing tests

When to use:

• Open-ended investigative tasks
• When the full scope is unknown up front
• When each step depends on the results of the previous step

8.3 Multi-pass Code Review

For pull requests with 10+ files:

Pass 1 (per-file): Analyze auth.ts -> list local issues
Pass 1 (per-file): Analyze database.ts -> list local issues
Pass 1 (per-file): Analyze routes.ts -> list local issues
...
Pass 2 (integration): Analyze relationships between files
  -> Cross-file issues: inconsistent types, circular dependencies

Why a single pass over 14 files is bad:

• Attention dilution: deep analysis for some files, shallow for others
• Inconsistent comments: a pattern is flagged in one file but approved in another
• Missed bugs: obvious errors get skipped due to cognitive overload