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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world scope, so the safety profile is covered. The description adds only the sort order (newest first) as extra behavior, and stays silent on the dual response shape (bare array vs { items, next_cursor, limit }) that meaningfully changes how a caller must handle results.

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?

A single short sentence with zero filler, and the useful ordering fact is stated immediately. Nothing is buried or padded.

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?

With only two optional params, full schema coverage and no output schema, this is close to adequate. But the tool has a non-obvious contract — omitting both params returns a legacy bare array while passing either returns a paginated envelope — and the description leaves that entirely to the schema, which an agent scanning descriptions may miss.

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 100%, and the param docs are unusually rich — they explain the limit/cursor interaction, the legacy bare-array fallback, and cursor opacity. The description itself contributes nothing beyond the schema, so the baseline 3 applies.

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?

"List your contact rows (newest first)" gives a specific verb and resource plus the default ordering, so the agent knows this is an unfiltered enumeration. It never names contact_search or contact_read, though, so an agent must infer on its own why to pick this over the filtering 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?

There is no explicit when-to-use or when-not-to-use guidance; the "(newest first)" note hints at a browse-all pattern but nothing steers the agent toward contact_search when filtering is needed. No prerequisites or pagination workflow are stated in the description.

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