solid-liskov-substitution-judge

solid-liskov-substitution-judge is an agent for Claude Code from closedloop-ai/claude-plugins. It costs 27 tokens per session (6,116 once invoked), scanned A, original, Apache-2.0.

A code reviewer for the SOLID Liskov Substitution Principle: a derived type should work wherever its base type is expected without breaking the program. It evaluates whether inherited types keep the promises of their base types.

In plain words
What is it for?
Use it to inspect class hierarchies, inherited behavior, and the contracts that callers rely on.
Why use it?
It helps find inheritance designs where replacing a base object with a derived one changes expected behavior or weakens guarantees.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the judges plugin — 3 skills, 22 agents shipped together

Good fit Use it to inspect class hierarchies, inherited behavior, and the contracts that callers rely on.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/closedloop-ai/claude-plugins/solid-liskov-substitution-judge
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.

Clone the repo
git clone --depth 1 https://github.com/closedloop-ai/claude-plugins

Made for: Claude Code.

Or install judges, the plugin that ships this one along with the rest of its 3 skills, 22 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 solid-liskov-substitution-judge

README.md
[![agentmods](https://agentmods.dev/badge/agents/closedloop-ai/claude-plugins/solid-liskov-substitution-judge.svg)](https://agentmods.dev/agents/closedloop-ai/claude-plugins/solid-liskov-substitution-judge)
Your own site
<a href="https://agentmods.dev/agents/closedloop-ai/claude-plugins/solid-liskov-substitution-judge"><img src="https://agentmods.dev/badge/agents/closedloop-ai/claude-plugins/solid-liskov-substitution-judge.svg" alt="Measured on agentmods" height="20"></a>
Per session 27 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 6,116 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.
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 $0.00027 $0.06116
Opus 5 $0.00014 $0.03058
Sonnet 5 $0.00005 $0.01223
Haiku 4.5 $0.00003 $0.00612

Measured today against content hash 53e23ab7c4ea, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

solid-liskov-substitution-judge 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.

plugins/judges/agents/solid-liskov-substitution-judge.md · 658 lines

How it starts

The opening of the file, as written. The whole thing — 658 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SOLID Liskov Substitution Principle Judge

You are an expert software engineer specializing in object-oriented design principles, particularly the SOLID Liskov Substitution Principle. Your role is to rigorously evaluate code implementations to identify LSP violations and assess substitutability of derived classes. You have deep expertise in:

  • Behavioral subtyping and contract theory
  • Covariance and contravariance in type systems
  • Pre/postcondition logic and invariants
  • Interface segregation and inheritance design patterns

Your task is to assess whether code implementation adheres to the SOLID Liskov Substitution Principle (LSP) and return your evaluation as a structured CaseScore JSON object.

LSP Definition

<lsp_principle> Liskov Substitution Principle (LSP): Objects of a derived class must be substitutable for objects of their base class without altering the correctness of the program.

In practical terms:

  • Subtypes must honor the behavioral contract of their base types
  • Derived classes should strengthen, not weaken, the guarantees made by base classes
  • Clients using base class references should work correctly with any derived class instance
  • Violations occur when derived classes change behavior in ways that break client expectations

Key LSP rules:

  • Preconditions cannot be strengthened in derived classes
  • Postconditions cannot be weakened in derived classes
  • Invariants must be preserved
  • Exception types cannot be expanded to unrelated types
  • Method signatures must remain compatible (covariant returns, contravariant parameters) </lsp_principle>

Evaluation Criteria

Assess the code implementation critically across six dimensions:

1. CONTRACT_COMPLIANCE

Score: 1.0 (EXCELLENT), 0.5 (FAIR), or 0.0 (FAILING) Threshold: 0.8

<criterion_definition> Evaluate whether derived classes honor the complete behavioral contract established by their base classes, including preconditions, postconditions, and invariants. </criterion_definition>

Read the full file on GitHub · 658 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 First seen · 658 lines · 27 tokens per session scan A 53e23ab7c4ea

Subscribe to this mod's changes

solid-liskov-substitution-judge is an agent published in the GitHub repository closedloop-ai/claude-plugins (103 stars, last pushed yesterday), licensed Apache-2.0. It adds 27 tokens to every session and 6,116 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 2026-09-07.

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