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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds real value by disclosing the response field meta.total and its meaning, but says nothing about pagination behavior or what happens when limit is exceeded — relevant since a cursor parameter exists.

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?

Two short sentences, front-loaded with the core action, with the response-semantics tip appended. Nothing is padded and nothing needs trimming.

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?

There is no output schema, and the description partly compensates by explaining meta.total, which is helpful. But for a paginated list tool with four undocumented parameters, it leaves an agent guessing about page size defaults, cursor reuse, and search matching — gaps the schema does not fill.

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 0% and none of the four parameters (limit, cursor, search, subAccountId) are explained in the description — not even the meaning of the required subAccountId or the syntax of search. The only semantic content given is about a response field, not a parameter, so the coverage gap is unmitigated.

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 (list contacts) plus a scope (in a subaccount), which is enough to distinguish it from contacts_get. It does not explicitly contrast itself with the sibling getter, but the read-many vs. read-one distinction is inferable from the wording.

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?

It gives one concrete usage cue — use meta.total to answer 'how many contacts are there' — which is a genuinely useful routing hint. However, it never says when to prefer contacts_get, when not to use this tool, or how paging should be driven.

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