Morgana: Skill for Claude Code

.claude/skills/harness-execution/SKILL.md

harness-execution is a skill for Claude Code from mdesalvo/Morgana. It costs 58 tokens per session (3,364 once invoked), scanned A, original, Apache-2.0.

A skill that runs PromptHarness, a test program for checking prompts against a configured language-model provider.

In plain words
What is it for?
Use it when you need to launch PromptHarness scenarios against the configured provider and choose which test classes and pass level to use.
Why use it?
It makes it possible to run selected prompt tests with a chosen pass threshold, while making the real model usage and cost explicit.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: names the AskUserQuestion tool.

This is mdesalvo/Morgana's own configuration. It tells Claude Code how to work on Morgana itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything Morgana configures →

Reuse

Borrowing it

Nothing to install: this file belongs to mdesalvo/Morgana. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/mdesalvo/Morgana/main/.claude/skills/harness-execution/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/mdesalvo/Morgana

Made for: Claude Code.

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-execution

README.md
[![agentmods](https://agentmods.dev/badge/skills/mdesalvo/morgana/harness-execution.svg)](https://agentmods.dev/skills/mdesalvo/morgana/harness-execution)
Your own site
<a href="https://agentmods.dev/skills/mdesalvo/morgana/harness-execution"><img src="https://agentmods.dev/badge/skills/mdesalvo/morgana/harness-execution.svg" alt="Measured on agentmods" height="20"></a>
Per session 58 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,364 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00058 $0.03364
Opus 5 $0.00029 $0.01682
Sonnet 5 $0.00012 $0.00673
Haiku 4.5 $0.00006 $0.00336

Measured today against content hash 120f4d28aa4d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

harness-execution 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 today.

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.

.claude/skills/harness-execution/SKILL.md · 189 lines

How it starts

The opening of the file, as written. The whole thing — 189 lines — stays where its author put it; the contents beside it link to each section on GitHub.

HarnessExecution

Runs the PromptHarness (PromptHarness/PromptHarness.csproj) on demand against whichever LLM provider is currently configured in User Secrets (Morgana:LLM:Provider), against a user-chosen scope and a user-chosen global run/pass threshold. Live LLM calls, real cost — never runs without the two questions below being answered first.

Trigger

Activated when the user says things like:

  • "run the harness"
  • "execute the prompt harness"
  • "launch the harness"
  • Any request to run PromptHarness scenarios against the current provider

Procedure

  1. Confirm the active provider before anything else: read Morgana:LLM:Provider from the shared User Secrets store (UserSecretsId 374228be-4f26-4382-a3ef-7500a0b829dd, same as Morgana.Web) without printing the ApiKey/Endpoint values and tell the user which provider/tier models (Tiers.Efficiency.Options.ModelId / Tiers.Performance.Options.ModelId) this run will hit. This is the harness's own design (PromptHarness/README.md): it never has its own Morgana: config, it inherits the host's. The same file is where Harness:HarnessDirectory lives when the user has overridden it (see step 7), so read both in one pass. Note the store is written with a UTF-8 BOM: parse it as utf-8-sig, or a plain JSON read fails on the first character.

  2. Ask the target scope with AskUserQuestion, multi-select. Enumerate PromptHarness/Tests/ first and offer what is actually there — the class list below is a description of a moving directory, not a contract, and a --filter naming a class that no longer exists runs zero tests and exits 0: a green nobody asked for. Thirteen classes at the time of writing, in four families:

    Deterministic — no model, no cost. Run them first: they are the cheapest way to learn the topology under test is sane before any billed turn.

    • Startup validation (StartupValidationTests — an incoherent partner declaration must stop the boot)
    • Agent card (AgentCardTests — the published card and how far the gate behind it reaches)
    • Peer federation (PeerFederationTests — the outbound half: which cards this side accepts, what it signs, where a credential may go)

Read the full file on GitHub · 189 lines

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. today Changed · +38 lines 120f4d28aa4d
  2. yesterday Changed 9cb506cbab5d
  3. 3d ago Changed · +14 lines 946ce9535c94
  4. 8d ago First seen · 137 lines · 58 tokens per session scan A 8f6b47acad37

Subscribe to this mod's changes

harness-execution is a skill published in the GitHub repository mdesalvo/Morgana (10 stars, last pushed today), licensed Apache-2.0. It adds 58 tokens to every session and 3,364 once invoked, about $0.0003 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 2026-08-31.

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