mcp-whatsapp

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search_contacts

Read-onlyIdempotent

Search cached WhatsApp contacts by name or phone number using case-insensitive substring matching. Works offline with local cache.

Instructions

(reads local cache; works while disconnected) Search the cached WhatsApp contact list by case-insensitive substring of name or phone number. Read-only; no side effects. Use is_on_whatsapp to verify whether an unknown phone number is registered. Returns a JSON array of contact objects (each with JID, push name, full name, and phone).

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "query": "<query>"
    },
    "name": "search_contacts"
  }
}

Input Schema

Name	Required	Description	Default
`query`	Yes	case-insensitive substring to match against name or phone

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.3.0May 16, 2026

changedInput schema / properties / query / description

Previous value: -"case-insensitive substring to match"New value: +"case-insensitive substring to match against name or phone"

First observedv0.1.0Apr 18, 2026

TDQS

A4.7/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare read-only and idempotent behavior. The description adds valuable context: it reads a local cache, works while disconnected, and has no side effects. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise, well-structured, and front-loaded with the essential detail about local caching and offline capability. Every sentence is informative with no redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple search tool with one parameter and no output schema, the description adequately covers return format (JSON array of contact objects with fields), search behavior, and operational context (cached, offline-capable).

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with a single parameter 'query' described as case-insensitive substring. The description restates this without adding new meaning, earning a baseline of 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool searches the cached WhatsApp contact list by case-insensitive substring of name or phone number. It distinguishes from sibling tool is_on_whatsapp by specifying that is_on_whatsapp should be used for checking unknown numbers.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly advises when to use the alternative tool is_on_whatsapp for verifying unknown phone numbers, and notes that search_contacts works while disconnected and reads local cache, guiding appropriate usage.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.