Plugin Types & Strategies DS003 / DS022 / DS027

MRP-VM expresses all domain behavior through four typed plugin families. The core kernel is neutral — it orchestrates plugin execution but never contains retrieval, normalization, or synthesis logic.

The Four Plugin Types

Type	Role	Built-in Implementations
`sd-plugin`	Seed detection: normalize user input into Intent CNL + context seeds	`sd-symbolic`, `sd-llm-fast`, `sd-llm-deep`
`kb-plugin`	Knowledge retrieval: goal-conditioned evidence gathering	`kb-fast`, `kb-balanced`, `kb-thinkingdb`
`gs-plugin`	Goal solving: produce grounded answer from evidence	`gs-symbolic`, `gs-llm-fast`, `gs-llm-deep`
`val-plugin`	Validation: verify answer is grounded and correct, reject to force replanning	`val-llm`
`mrp-plan-plugin`	Meta-rational planning: order plugin execution per request	`planner-default`, `planner-depth`

Execution Flow

Request → Planner builds plan
  → sd-plugin candidates (first success)
  → parser/decomposer (shared services)
  → kb-plugin candidates (first sufficient)
  → gs-plugin candidates (first success or no-context fallback)
  → val-plugin validates answer (reject → replan)
→ Response

Fallback & Backtracking

Each stage tries candidates in planner-determined order. If a plugin returns unsupported or error, the next candidate is tried. Three levels of backtracking:

Intra-stage: next plugin candidate within the same stage
Cross-planner: if all stages fail, try the next planner (e.g. planner-depth)
Weak recovery: if only no-context results are produced, accept the best weak answer rather than failing

Plugin Descriptor

Every plugin exposes a descriptor (DS003):

{
  id: "kb-balanced",
  type: "kb-plugin",
  costClass: "moderate",
  usesLLM: false,
  maxLLMCalls: 0,
  modelRoles: [],
  plannerHints: {
    supportedActs: ["compare", "explain"],
    topicTags: ["technical"],
    preferredDepth: "medium",
    evidenceStyle: ["hybrid"]
  }
}

Legacy Compatibility

The old processing_mode and retrieval_profile concepts map to typed plugins:

Legacy	Plugin Equivalent
`symbolic-only`	`sd-symbolic` + `gs-symbolic`
`llm-assisted`	`sd-llm-fast` + `gs-llm-fast`
`fast` profile	`kb-fast`
`balanced` profile	`kb-balanced`
`thinkingdb` profile	`kb-thinkingdb`

Legacy fields are derived from plugin IDs for API compatibility but are not stored on sessions.

← Retrieval Planner →