On-Demand Plugin Synthesis + Plugin Hub for `run_plan_pipeline.py`

Pitch

Automatically synthesize new plugins when a plan needs a capability that does not exist, and publish them into a shared plugin hub with testing and governance.

Why

PlanExe encounters novel plan types where existing plugins do not apply. Manual plugin development slows throughput. On-demand synthesis enables rapid capability expansion while maintaining quality controls.

Problem

Missing plugins block automation.
Plugin creation is slow and inconsistent.
No repeatable pathway from “missing capability” to reusable plugin.

Proposed Solution

Create a synthesis hub that:

Detects missing capabilities from plan requirements.
Generates a plugin scaffold and implementation.
Tests the plugin against benchmark tasks.
Publishes approved plugins into the hub.

Synthesis Workflow

1) Capability Gap Detection

Identify missing task coverage from plan parsing.
Use plugin registry to find near matches.
Trigger synthesis only when no adequate plugin exists.

2) Plugin Synthesis

Generate a specification: inputs, outputs, constraints.
Produce code and test cases.
Add documentation and metadata.

3) Validation

Run benchmark harness for quality and safety.
Validate schema compatibility.
Assign trust tier based on results.

4) Publication

Versioned release to plugin hub.
Attach synthesis provenance and evaluation results.
Enable future adaptations via lifecycle workflows.

Plugin Spec Template

{
  "name": "cost_estimation",
  "inputs": ["plan_json"],
  "outputs": ["cost_breakdown"],
  "constraints": ["deterministic", "schema_validated"],
  "tests": ["golden_case_1", "edge_case_2"]
}

Output Schema

{
  "plugin_id": "plug_900",
  "origin": "synthesized",
  "capability": "cost_estimation",
  "status": "approved",
  "trust_tier": "Tier 1"
}

Integration Points

Feeds into plugin hub discovery and ranking.
Uses benchmarking harness for validation.
Enforces safety governance for runtime loading.

Success Metrics

Reduced time to add new capabilities.
% synthesized plugins accepted after testing.
Increase in task coverage across domains.

Risks

Synthesized plugins may be brittle or unsafe.
Over-generation of low-value plugins.
Increased governance burden.

Future Enhancements

Human review gates for sensitive plugins.
Continual learning from production failures.
Automatic deprecation of low-usage plugins.

Detailed Implementation Plan

Phase A — Missing Capability Detection

Add stage-level capability requirement declarations.
Detect unresolved capability failures at runtime.
Emit synthesis request objects with strict interface contracts.

Phase B — Synthesis Sandbox

Generate plugin skeletons in isolated environment.
Run contract tests, linting, and security scans.
Reject non-compliant plugins automatically.

Phase C — Hub Registration and Reuse

Register validated plugins with version + checksum.
Add capability-indexed lookup for future runs.
Track reuse telemetry and quality outcomes.

Validation Checklist

Recovery rate for missing-capability failures
Plugin quality gate pass rate
Reuse lift across subsequent plans

On-Demand Plugin Synthesis + Plugin Hub for run_plan_pipeline.py