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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description layers on genuinely new operational facts: retention windows by plan tier (7/30/90/365 days), that the call is free, and the shape of each returned answer (headline, points, caveat, sources). These are the details that determine whether the agent can rely on historical data existing.

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?

Three tight sentences with zero filler: the return shape and ordering come first, then retention limits, then the usage cue and cost. Every sentence carries distinct information.

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, the description compensates by naming the returned fields, and it covers retention, ordering, scope, and cost for a trivial one-parameter read tool. An agent has everything needed to decide whether to call it and what it will get back.

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?

There is a single optional parameter with 100% schema description coverage, and the description adds nothing about `limit` beyond what the schema already states ('newest first', default). Baseline 3 is appropriate when the schema carries the parameter burden entirely.

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 names a specific verb+resource ('the signed-in account's own recent questions to DatosIA and the answers it was shown') and immediately enumerates the returned fields, so it is unmistakable against siblings like search_research or query_data. Scope (own account only) and ordering (newest first) are both stated.

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 a clear use case: 'Use it to pick up an earlier line of research,' which tells the agent this is a retrieval-of-own-history tool rather than a fresh search. It does not explicitly name an alternative (e.g. re-running search_research), so it falls short of a full when/when-not statement.

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