harness-optimizer

harness-optimizer is an agent for coding agents from affaan-m/ECC. It costs 21 tokens per session (181 once invoked), scanned A, original, MIT.

An agent for analyzing and improving the configuration around coding agents, known as the agent harness. It examines hooks, evaluations, routing, context, and safety settings rather than the product's application code.

In plain words
What is it for?
Use it to audit a harness, identify the three biggest improvement areas, apply small reversible changes, validate them, and report baseline and after-change results.
Why use it?
It helps make agent runs more reliable, affordable, and efficient while measuring whether configuration changes improve results.

Agent

Part of the ecc plugin — 39 skills, 3 commands, 15 agents shipped together

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/affaan-m/ecc/harness-optimizer
Clone the repo
git clone --depth 1 https://github.com/affaan-m/ECC

Or install ecc, the plugin that ships this one along with the rest of its 39 skills, 3 commands, 15 agents.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for harness-optimizer

README.md
[![agentmods](https://agentmods.dev/badge/agents/affaan-m/ecc/harness-optimizer.svg)](https://agentmods.dev/agents/affaan-m/ecc/harness-optimizer)
Your own site
<a href="https://agentmods.dev/agents/affaan-m/ecc/harness-optimizer"><img src="https://agentmods.dev/badge/agents/affaan-m/ecc/harness-optimizer.svg" alt="Measured on agentmods" height="20"></a>
Per session 21 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 181 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00021 $0.00181
Opus 5 $0.00010 $0.00090
Sonnet 5 $0.00004 $0.00036
Haiku 4.5 $0.00002 $0.00018

Measured 4d ago against content hash 4f93d025ee77, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

harness-optimizer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

8 near-identical copies found in the catalogue:

.kiro/agents/harness-optimizer.md · 35 lines

What it actually says

You are the harness optimizer.

Mission

Raise agent completion quality by improving harness configuration, not by rewriting product code.

Workflow

  1. Run /harness-audit and collect baseline score.
  2. Identify top 3 leverage areas (hooks, evals, routing, context, safety).
  3. Propose minimal, reversible configuration changes.
  4. Apply changes and run validation.
  5. Report before/after deltas.

Constraints

  • Prefer small changes with measurable effect.
  • Preserve cross-platform behavior.
  • Avoid introducing fragile shell quoting.
  • Keep compatibility across Claude Code, Cursor, OpenCode, and Codex.

Output

  • baseline scorecard
  • applied changes
  • measured improvements
  • remaining risks
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 35 lines · 21 tokens per session scan A 4f93d025ee77

Subscribe to this mod's changes

harness-optimizer is an agent published in the GitHub repository affaan-m/ECC (245,751 stars, last pushed 2d ago), licensed MIT. It adds 21 tokens to every session and 181 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.