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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds that the result is paginated, but it omits ordering, what the timeline contains (events? notes?), and the presence of a pageToken cursor alongside limit/offset. This is useful but incomplete behavioral context.

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, front-loaded sentences with no filler. It is appropriately sized but thin given the missing parameter detail, so it is efficient rather than exemplary.

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 no output schema, no schema descriptions, and four parameters including a required contactId and an undocumented pageToken, the description leaves an agent unable to know what the timeline returns or how to paginate correctly. It does not compensate for the missing structured information.

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%, so the description must carry parameter meaning. It mentions limit and offset only, leaving contactId (the required parameter) and pageToken completely unexplained, including how pageToken relates to offset-based pagination.

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 ('Restituisce la timeline di un contatto della rubrica'), which is clearly distinct from siblings like contacts.get or contacts.search. It does not explicitly name a sibling alternative, keeping it at 4 rather than 5.

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 guidance on when to use this tool instead of contacts.get, contacts.search, or events-related siblings. The only hint is the mention of pagination support, which is a capability, not a usage condition.

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