---
id: "question-jit-tool-assembly"
type: "open-question"
source_timestamps: ["§ Where Harness Engineering is Going"]
tags: ["tool-use", "context-management"]
related: ["concept-progressive-disclosure", "prereq-mcp"]
resolutionPath: "Advancing progressive disclosure techniques and semantic routing to fetch and inject MCPs/tools based on real-time task decomposition."
---
# Just-In-Time Tool Assembly

## The Question

How can harnesses **dynamically assemble the right tools and context just-in-time** for a given task, rather than relying on pre-configured environments?

## Resolution Path

Likely directions:

- **Advanced [[concept-progressive-disclosure|progressive disclosure]]** that decomposes the user's request and fetches the matching skill set.
- **Semantic routing over MCP catalogs** — embed task descriptions, retrieve relevant [[prereq-mcp|MCP]] servers, mount them on the fly.
- **Real-time task decomposition** — a planner subagent that emits the tool manifest needed for each subtask.

## Why It Matters

The current state-of-the-art ships harnesses with fixed (or coarsely tiered) tool catalogs. A truly JIT harness would scale to **arbitrary domains** without context bloat — directly attacking the early-context-rot problem identified in [[concept-context-rot]].