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

Annotations already establish read-only, non-destructive, open-world behavior. The description adds useful context beyond that: Dex's list omits email and phone, and a truncated result must be surfaced to the user. It still omits pagination and search semantics, but covers the key behavioral caveats.

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?

Four short sentences, each carrying operational value: scope, missing fields, sibling routing, agent_name requirement, truncation handling, and read-only status. No repetition or filler.

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?

The output schema and annotations cover return shape and safety, and the description adds important caveats about missing contact data and truncated results. However, with five parameters at low schema coverage, it leaves filtering, pagination, and connectionId usage insufficiently explained.

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?

Schema description coverage is only 20%, so the description needs to compensate for five parameters. It clarifies agentName and implies query through 'searches', but gives no meaning for companyId, maxResults, or the nested connectionId parameter.

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?

States a specific verb and resource ('Lists or searches contacts in ... Dex'), names the returned fields, and distinguishes itself from connection_get_dex_contact. An agent can immediately tell what this tool does and how it differs from the detail-fetch sibling.

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?

Explicitly routes the agent to connection_get_dex_contact for one person's details and history, and tells it to pass agent_name. It does not mention when to prefer connection_list_connected_contacts or when not to use this tool, so it falls short of full alternative coverage.

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