list_contacts

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

The description discloses a non-obvious response format behavior: results are wrapped in a {'total','items'} envelope when a total count is reported, otherwise a bare array. With no annotations provided, this is valuable context, though it doesn't cover other traits like authentication or rate limits.

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

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

The description is two sentences, front-loaded with the primary purpose, followed by the response format note. Every word earns its place.

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

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

For a simple list tool with one parameter and no output schema, the description adequately covers the main purpose and the variable response envelope. It could mention sorting or error behavior but the current scope is reasonably complete.

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

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

The schema already fully documents the 'limit' parameter with a clear description and default value. The tool description adds no additional parameter information, so baseline 3 applies per schema coverage rules.

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

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

The description clearly states 'List contacts from the address book', using a specific verb and resource. It distinguishes from sibling tools like search_contacts and get_contact by indicating a full listing operation.

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

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

The description implies this tool is for listing all contacts but does not explicitly state when to use it versus alternatives like search_contacts. No exclusions or alternative guidance are provided.

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