What is core CLAUDE.md?

A set of instructions for Claude Code in the module-federation/core codebase. It tells the coding agent to split development work into parallel tasks and gives guidelines for doing so.

Use it when implementing or changing features across source code, tests, configuration, documentation, builds, or separate modules.

It gives the agent a consistent way to divide large codebase tasks, reducing the need to manage every subtask manually.

How module-federation/core configures Claude Code

About the project

Module Federation is a system for sharing code, resources, and dependencies between separate JavaScript applications, allowing a large application to be split into independently developed micro-frontends. It is used by web developers building applications from multiple cooperating front-end modules, with runtime loading, manifests, type hints, and plugins supporting that architecture.

module-federation/core · 2,677 stars · on GitHub · module-federation.io

Reuse

Borrowing it

Nothing to install: this file belongs to module-federation/core. 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/module-federation/core/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/module-federation/core

Made for: Claude Code.

Wrote this? Show the measurements

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README.md

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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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/module-federation/core/claude-md"><img src="https://agentmods.dev/badge/instructions/module-federation/core/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 3,933 This file is loaded in full into every session.

When invoked 3,933 The same file — it is already loaded in full.

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.

Model	Per session	Once invoked
Fable 5.1	$0.03933	$0.03933
Opus 5.5	$0.01573	$0.01573
Sonnet 5.5	$0.00787	$0.00787
Haiku 4.5	$0.00393	$0.00393

Measured 2mo ago against content hash 47644565a84e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

core CLAUDE.md 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 2mo 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.

CLAUDE.md · 341 lines

How it starts

The opening of the file, as written. The whole thing — 341 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Claude Task Parallelization & Development Guidelines

Core Principles

Maximum Parallelization Strategy

ALWAYS PARALLELIZE: Break down ANY task into multiple parallel sub-tasks
IMMEDIATE EXECUTION: Launch parallel Task agents immediately without asking questions
NO CLARIFICATION: Skip asking about implementation details unless absolutely critical
CONTEXT EFFICIENCY: Each task handles only its specific scope to minimize token usage

Universal Parallel Task Patterns

For Any Codebase Task

Analyze the request and immediately split into parallel tasks based on:

File Type Separation
- Source code files
- Test files
- Configuration files
- Documentation files
- Build/deployment files
Functional Separation
- Core implementation
- Helper/utility functions
- Integration points
- Data models/schemas
- External interfaces
Directory-Based Separation
- Different modules/packages
- Frontend vs backend
- Library vs application code
- Public vs private APIs

Dynamic Task Allocation Examples

Example 1: Feature Implementation (5-7 parallel tasks)

Task 1: Core feature logic
Task 2: Supporting utilities/helpers
Task 3: Tests (if applicable)
Task 4: Integration with existing code
Task 5: Configuration updates
Task 6: Type definitions (if typed language)
Task 7: Remaining changes and coordination

Example 2: Bug Investigation (3-10 parallel tasks)

Task 1: Search for error patterns in logs/code
Task 2: Analyze related test files
Task 3: Check recent commits/changes
Task 4: Investigate similar issues in codebase
Task 5: Review documentation/comments

Example 3: Refactoring (4-6 parallel tasks)

Task 1: Identify all usage locations
Task 2: Plan new structure
Task 3: Update core implementations
Task 4: Update dependent code
Task 5: Update tests
Task 6: Verify no breaking changes

Example 4: Codebase Analysis (5-8 parallel tasks)

Task 1: Analyze file structure
Task 2: Review core business logic
Task 3: Map dependencies
Task 4: Identify patterns/conventions
Task 5: Review configuration
Task 6: Analyze build system
Task 7: Check documentation
Task 8: Security/performance patterns

Read the full file on GitHub · 341 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.

2mo ago First seen · 341 lines · 3,933 tokens per session scan A 47644565a84e

Subscribe to this mod's changes

core CLAUDE.md is an instructions file published in the GitHub repository module-federation/core (2,677 stars, last pushed today), licensed MIT. It adds 3,933 tokens to every session, about $0.0157 per session on Opus 5.5. 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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core: Instructions file for Claude Code