reconcile-code

reconcile-code is a skill for Claude Code from kotaroyamame/formal-agent-contracts. It costs 89 tokens per session (5,028 once invoked), scanned A, original, MIT.

A comparison and repair workflow for checking existing code against a confirmed VDM-SL specification. VDM-SL is a formal language for describing software behaviour and data precisely.

In plain words
What is it for?
Use it to compare type definitions and other specified behaviour item by item. It produces a difference report, prioritised fixes, and automatically generated tests.
Why use it?
It exposes where the code and specification disagree, including missing fields, extra fields, incorrect types, and mismatched optional values. This gives developers a structured list of changes and tests to make.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the formal-agent-contracts plugin — 15 skills shipped together

Good fit Use it to compare type definitions and other specified behaviour item by item. It produces a difference report, prioritised fixes, and automatically generated tests.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/kotaroyamame/formal-agent-contracts/reconcile-code
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.

Any agent
npx skills add kotaroyamame/formal-agent-contracts --skill reconcile-code
Clone the repo
git clone --depth 1 https://github.com/kotaroyamame/formal-agent-contracts

Made for: Claude Code.

Or install formal-agent-contracts, the plugin that ships this one along with the rest of its 15 skills.

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 reconcile-code

README.md
[![agentmods](https://agentmods.dev/badge/skills/kotaroyamame/formal-agent-contracts/reconcile-code/github.svg)](https://agentmods.dev/skills/kotaroyamame/formal-agent-contracts/reconcile-code)
Your own site
<a href="https://agentmods.dev/skills/kotaroyamame/formal-agent-contracts/reconcile-code"><img src="https://agentmods.dev/badge/skills/kotaroyamame/formal-agent-contracts/reconcile-code/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for reconcile-code

Your own site · 80×15
<a href="https://agentmods.dev/skills/kotaroyamame/formal-agent-contracts/reconcile-code"><img src="https://agentmods.dev/badge/skills/kotaroyamame/formal-agent-contracts/reconcile-code.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 89 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,028 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 $0.00089 $0.05028
Opus 5 $0.00044 $0.02514
Sonnet 5 $0.00018 $0.01006
Haiku 4.5 $0.00009 $0.00503

Measured 9d ago against content hash 24cc4dc63627, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

reconcile-code 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 9d 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.

skills/reconcile-code/SKILL.md · 554 lines

How it starts

The opening of the file, as written. The whole thing — 554 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Reconcile Code Skill

Overview / 概要

This skill reconciles existing code with a confirmed VDM-SL specification through systematic comparison, generates diff reports, produces prioritized code fixes, and auto-generates comprehensive tests.

このスキルは、確認済みのVDM-SL仕様との間で既存コードを体系的に比較し、差分レポートを生成し、優先度付きコード修正を生成し、包括的なテストを自動生成します。


Step 1: Item-by-Item Comparison

Type Definitions

EN: For each VDM-SL type definition in the confirmed spec, locate the corresponding code type (TypeScript interface/type, Python dataclass, etc.):

  • Verify all field names match spec exactly
  • Verify all field types match spec types (accounting for language-specific representations)
  • Verify optional/required markers match (nullable, Optional[], etc.)
  • Check for extra fields in code not in spec
  • Check for missing fields in code that are in spec

JP: 確認済み仕様のVDM-SL型定義ごとに、対応するコード型(TypeScriptインターフェース/型、Pythonデータクラスなど)を見つけます:

  • すべてのフィールド名が仕様と正確に一致することを確認
  • すべてのフィールド型が仕様型と一致することを確認(言語固有の表現を考慮)
  • オプション/必須マーカーが一致することを確認(nullable、Optional[]など)
  • 仕様にない仕様にないコード内の余分なフィールドをチェック
  • 仕様にあるがコードにない欠落フィールドをチェック

Status Codes:

  • ✅ Match: All fields present, types correct, required/optional markers align
  • ⚠️ Partial: Some fields missing/extra, or minor type representation differences that don't affect runtime
  • ❌ Mismatch: Type definitions are incompatible, will cause runtime errors
  • 🔍 Not Found: No corresponding type found in code

Pre-conditions

EN: For each VDM-SL pre-condition (guards in the function specification), find the corresponding code implementation:

  • Look for guard clauses, early returns with error checks, parameter validation
  • Verify the guard logic is equivalent to the pre-condition
  • Check that appropriate errors/exceptions are thrown on violation
  • Identify if the guard is implicit (e.g., type system enforces) or explicit (runtime check)

JP: VDM-SL仕様の各前提条件(関数仕様のガード)について、対応するコード実装を見つけます:

  • ガード句、エラーチェック付きの早期リターン、パラメータ検証を探す
  • ガードロジックが前提条件と等価であることを確認
  • 違反時に適切なエラー/例外がスロウされることを確認
  • ガードが暗黙的(型システムが強制)か明示的(実行時チェック)かを識別

Read the full file on GitHub · 554 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 9d ago First seen · 554 lines · 89 tokens per session scan A 24cc4dc63627

Subscribe to this mod's changes

reconcile-code is a skill published in the GitHub repository kotaroyamame/formal-agent-contracts (1 stars, last pushed 2mo ago), licensed MIT. It adds 89 tokens to every session and 5,028 once invoked, about $0.0004 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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