Add AGENTS.md + cross-tool redirects for AI coding agents

[ord669]

Summary

• Adds AGENTS.md at repo root — the self-contained guide any AI coding agent (Claude Code, Cursor, Codex, Gemini CLI, GitHub Copilot) reads when a user clones this kit and asks their agent to wire up WhatsApp via @gethookmyapp/cli. Covers sandbox quickstart, production setup, signature verification, HUMAN ACTION REQUIRED steps, and safety rules.
• Adds 4 thin redirects so each tool's auto-loaded file points at AGENTS.md: CLAUDE.md, GEMINI.md, .cursorrules, .github/copilot-instructions.md.
• Adds a "For AI Agents" section near the top of README.md so human readers see the affordance exists.

Why

Today the README is human-oriented. When a user opens this kit in their AI agent and says "wire this up to WhatsApp," the agent has no auto-loaded context telling it the CLI exists, what commands to run, or which steps need human browser interaction. This change installs the AGENTS.md cross-tool standard plus tool-specific redirects so every major AI coding tool finds the same guidance with zero configuration.

Test plan

• Open this branch in Claude Code; ask "how do I wire this kit up to WhatsApp?" — verify Claude reads CLAUDE.md → AGENTS.md and walks through hookmyapp sandbox env --write .env + npm start + hookmyapp sandbox listen without inventing commands.
• Repeat in Cursor (.cursorrules) and Gemini CLI (GEMINI.md) — same expected behaviour.
• Skim AGENTS.md as a human and confirm: 5 sandbox env keys listed, signature snippet matches src/index.js shape, HUMAN ACTION REQUIRED blocks present for login + channels connect, safety rules cover credential redaction + production webhook URL confirmation.
• Confirm README.md's existing sections are unchanged below the new "For AI Agents" block.

Summary by CodeRabbit

• Documentation
  • Added comprehensive AI agent guidance covering sandbox quickstart, production setup, signature verification, and credential-safety rules.
  • Added AI agent pointers across multiple platforms to centralized configuration guidance.
  • Updated README with "For AI Agents" section directing to new guidance documentation.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: a49467ac-fea2-4cee-b5b6-c05bf351e06f

📥 Commits

Reviewing files that changed from the base of the PR and between 208fc53 and 6b6e0d9.

📒 Files selected for processing (6)

• .cursorrules
• .github/copilot-instructions.md
• AGENTS.md
• CLAUDE.md
• GEMINI.md
• README.md

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📝 Walkthrough

Walkthrough

This pull request adds comprehensive AI-agent guidance documentation to the repository. It introduces AGENTS.md as a central resource covering sandbox quickstart, production setup, webhook signature verification, and environment configuration. Tool-specific files (.cursorrules, .github/copilot-instructions.md, CLAUDE.md, GEMINI.md) and a README section redirect AI agents to AGENTS.md.

Changes

Cohort / File(s)	Summary
AI Agent Guidance Hub AGENTS.md	Comprehensive single-source-of-truth documentation for AI agents: Express webhook receiver behavior, CLI responsibility division, five .env keys, sandbox quickstart workflow, production setup steps, signature verification details, troubleshooting table, and going-further references.
Tool-Specific AI Pointers .cursorrules, CLAUDE.md, GEMINI.md, .github/copilot-instructions.md	Brief configuration/documentation files redirecting AI agents to consult AGENTS.md before suggesting HookMyApp / WhatsApp Cloud API code.
User-Facing Documentation README.md	New "For AI Agents" section informing users to reference AGENTS.md for wiring the kit with AI coding assistants.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

🐰✨ Fresh guidance files now bloom,
AI agents find their way home,
From Cursor to Claude, Gemini too—
One source of truth to light the view! 🌙

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately and specifically describes the main change: adding AGENTS.md documentation and cross-tool redirect files for AI coding agents.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch agents-md-cross-tool-redirects

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