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jev-context-filter-harness

zacharytgray/jev-context-filter-harness

Screening LLM agent tool output for relevance and prompt injection with Jev.

Verification & Guardrails0.99Runner-up: Evaluation & Benchmarking
Automated README summary

Automatically summarized from the README on 13 Oct 2026; not a run by jevbooks. Run instructions and author-reported outcomes still need verification.

What it is

A harness for LLM agents that screens tool output before the agent reads it. Two filters (relevance and injection) sit between the agent's tools and the agent. Tested with three agent models on three search-heavy test beds and AgentDojo.

How it uses Jev

Both filters ask Jev, a hosted classifier model, typed questions about each chunk of a tool output. The relevance filter keeps chunks that answer the agent's own question about the call. The injection filter withholds lines that try to give the agent a task the user did not ask for.

Primitives:choicescorenoul

Technique worth stealing

Using a hosted System One classifier to screen tool output for relevance and prompt injection before the agent reads it.

View on GitHub

Start using Jev: API key and your first request →

Model judgments from README excerpts

Project signals use repository metadata, an existing summary and the first 700 README characters, not the full project. “Not found” means not detected in that material; it does not establish absence. These are the original judgments with recorded models and dates, not source audits or run results.

Models & evaluation dates

Inclusion gate
jev-1.13.0
Project signals
jev-1.13.0
Category
jev-1.13.0
Pattern tags
jev-1.13.0

Evidence

These signals use repository metadata, an existing summary and at most 700 cleaned README characters. ≥ 0.60 means reported in that excerpt; ≤ 0.40 means not found there. The middle band is inconclusive. None is a source-code audit or a test result. The runnable-tool question excludes research experiments; the recommendation question asks for a learning shortlist, not a quality verdict.

  • Jev is core to the projectFound in material0.89
  • Shows a System One patternFound in material0.77
  • Describes handling uncertaintynot found in the excerpt0.07
  • Reports measured numbersnot found in the excerpt0.08
  • Is a runnable toolnot found in the excerpt0.16
  • Top-10 learning shortlist signalunclear0.51
  • Is a replica of the modelnot found in the excerpt0.04
  • Solves a common problem (0–2)score on a 0–2 scale1.94 / 2
  • About JevFound in material0.97
Signals
Jev is core to the project0.89Shows a System One pattern0.77Describes handling uncertainty0.07Reports measured numbers0.08Is a runnable tool0.16Top-10 learning shortlist signal0.51Is a replica of the model0.0400.51Solves a common problem (0–2)1.94 / 2012

no-judgment band (0.40–0.60)

Design patterns
Funnel0.39Viewfinder0.33Grey zone0.2800.51

no-judgment band (0.40–0.60)

The Jev model and date for each judgment stage are listed above. Card written by DeepSeek V4.1 Flash from the README on 13 Oct 2026.