Will the router hide tools my agent actually needs?

No. A miss returns a bounded ranked shortlist with guidance for targeted search and paginated listing, and full listing remains as an explicit last resort. Every turn stays reversible.

Why tournament-batch instead of sending the whole inventory?

The model documents separate request and state-plus-question limits, and the router budgets conservatively with pessimistic size estimates. Oversized inventories fall back to tournament batching with minimum-confidence propagation.

What does setup change in my Codex config, and is it safe?

The setup script previews changes first, backs up configs, leaves native entries direct, preserves allow lists and timeouts, and skips credential-bearing or auth-sensitive entries. Apply is explicit and rerunnable.

What happens when the selected tool call fails at runtime?

Failures return a compact fallback-required response with a shortlist instead of echoing upstream error bodies, and mutating tools are not auto-replayed after uncertain transport failures. A separate Jev call can score completed work on satisfaction and quality.

What does Jev actually see during routing?

The capability the agent is looking for, optional task context, and tool names and descriptions. It does not receive every full input schema before a tool is selected, and every routing choice includes none_of_the_above so nothing is forced.

What context budgets does the router enforce?

Before each Jev routing call it estimates the serialized size against conservative ceilings: 24k estimated tokens for state plus the longest question, 48k for the whole request and 6k for optional routing context. Oversized inventories fall back to tournament batching instead of awaiting a rejection.

What does the work-evaluation workflow score?

A second Jev workflow, reached with evaluate_work_with_jev, scores completed work on requirement satisfaction, completion and revision probabilities, a 0-4 quality rubric, and a primary issue category.

CommunityJev Agents & MCP

Jev Tool Router

MCP tool router for Codex that keeps large external tool inventories behind a small find_tool surface and asks Jev to select from names and descriptions at a 0.90 threshold, falling back to bounded search.

See highlights

Open github.com

Stars: 9
Language: JavaScript
License: MIT
Published by: Community
Author: jackbarunz
Last verified: Oct 2026

jackbarunz/jev-tool-router

User repository on GitHub

View on GitHub

Jev-powered MCP tool routing for Codex

Forks: 1
Last pushed: Updated Sep 2026

Repo stats from the GitHub API, cached Oct 2026.

About this project

Jev-powered MCP tool routing for Codex. Unofficial community project. Not affiliated with or endorsed by TypeSafe AI, Vercel, or OpenAI. Instead of exposing hundreds of external MCP tool schemas directly to the agent, Jev Tool Router exposes a small routing surface and resolves external tool discovery on demand. v Jev sees request + tool names + descriptions. v v one tool + schema compact shortlist. v v call tool targeted search.

Quoted from the project's README. Read the full README.

Tagscommunity jevbest catalog-import

Works forJev for Classification Jev for Routing Jev for Tool calling

Used inJev for Software & DevTools

Languages: JavaScript

Highlights

Exposes a small router surface while the full inventory stays reachable through paginated search and last-resort listing.
Preflight size estimation with conservative budgets and tournament batching keeps large inventories inside model limits.
Setup migration previews, backs up configs, preserves allow lists and timeouts, and skips credential-bearing entries.
Separate Jev workflow scores completed work on requirement satisfaction, completion, revision risk, and a 0-4 quality rubric.

Watch out

Thresholds, budgets, and migration behavior are configurable, so verify them against your own tool inventory before hiding direct tools. Copy reviewed against the repository README on 2026-10-04, not from running it.

Questions about this entry

Short answers drawn from the linked project or page.

More Jev resources like this

codex-jev-router

A local MCP server that gives Codex a few cited excerpts instead of a whole noisy search result, with a deterministic default selector that needs no Jev account or key.