Skip to content

Which path: card vs MethodPolicy vs full port vs aggregator_factory

Usability pillars: call any algorithm, quickly implement a new one. This page is the map. Same name ≠ same fidelity — an Algorithm card such as "algorithm": "gepa" is not the examples/gepa/ research port (port fidelity; cards-only contract closed via #384).

Hard contract: cards vs ports (#384)

Path A (agentdescent CLI / MCP / host plugins) can name Algorithm cards shipped in the wheel. It does not run the full examples/<algo>/ research ports.

Surface What it is How you run it
Card (surface=card) Mechanism slice in the wheel (agentdescent algorithms list) "algorithm": "gepa" in a spec / /algorithms run
Port Source-only paper script under examples/ python -m examples.gepa… from a checkout

Same slug ≠ same fidelity. A card may share a name with a port (ACE, GEPA, DGM, SkillOpt, EvoSkill, …) and still be only a mechanism slice — plan / show echo fidelity, research_port, fidelity_note. Never imply paper benchmark numbers from a card run. MethodPolicy microports stay under examples/ until someone opens a scoped card issue for one of them.

Future card candidates (not promised): Voyager / SkillWeaver / Reflexion / Self-Refine / TextGrad MethodPolicy mechanisms — each needs its own issue with kinds, params, fidelity class, and deviation vs examples/<algo>/.

Decision tree

If you need… Prefer… Fidelity / surface Example
Swap one decision rule (selection / acceptance / merge / …) on the single-head loop Policies / SHORT_REFS / a small Algorithm card preset or mechanism_microport; surface=card archive_selection card; register a card
Paper method with custom propose/solve/reward but still a single-head Policies loop MethodPolicy microport under examples/ mechanism_microport (matrix) porting-methodpolicy.md; e.g. Reflexion, TextGrad scripts
Multi-head / population / Pareto archive / keep-all search that the ledger head cannot express aggregator_factory= (or a card that sets one) Usually mechanism_microport on the card; paper numbers stay on the full port GEPA / DGM / SkillOpt / EvoSkill cards; see aggregator-factory.md
Reproduce paper numbers on fixed data Full examples/<algo>/ research port benchmark_faithful python -m examples.gepa… from a source checkout (porting-checklist.md) 
need a name hosts can pick? ──yes──► Algorithm card (this package / wheel)
        │                              filter by kind; plan echoes fidelity
        │
        no (research only)
        │
        ├── single-head + custom propose/reward ──► MethodPolicy microport
        ├── population / Pareto / keep-all ───────► aggregator_factory
        └── paper numbers on fixed data ──────────► full examples/<algo>/ port

Factory path: which Policies fields still apply

aggregator_factory= replaces the shipped merge pipeline. Merge-side Policies slots the default path would wire — especially conflict, fusion, acceptance, promotion — do not reach a factory-built aggregator through the bundle unless the factory itself reads them. Carrying them in both places is a silent drop on the evolve path today; plan warns when it can see the mismatch (#504).

Factory ⊕ merge Policies composition landed via #807 / #813: evolve forwards merge-side slots into the factory (or onto the returned aggregator) and raises on unused requested slots unless Policies(accept_orphaned_merge_policies=True). Details: aggregator-factory.md.

selection + aggregator_factory together are refused (both fill the aggregator seat) — that is already loud.

Worked miniatures

  1. Card (Policies only). "algorithm": "archive_selection" — only parent sampling changes; propose / merge / acceptance stay the engine default.
  2. Card (factory). "algorithm": "gepa" — Pareto pool via aggregator_factory; plan notes the merge/acceptance path is replaced; fidelity is mechanism_microport, not the HotpotQA examples/gepa/ port.
  3. MethodPolicy. python -m examples.reflexion… — custom propose/reward on the shared MethodPolicy runner; not in the wheel catalog.
  4. Full port. python -m examples.gepa.gepa_prompt_evolution — paper data, paper reward, paper loop; source checkout only.