---
title: On-Demand Plugin Synthesis + Plugin Hub for `run_plan_pipeline.py`
date: 2026-02-10
status: proposal
author: Larry the Laptop Lobster
---

# 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:

1. Detects missing capabilities from plan requirements.
2. Generates a plugin scaffold and implementation.
3. Tests the plugin against benchmark tasks.
4. 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

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

## Output Schema

```json
{
  "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

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

### Phase B — Synthesis Sandbox

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

### Phase C — Hub Registration and Reuse

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

### Validation Checklist

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

