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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds substantive traits beyond that: one story per event (deduplication), newest-first ordering, the publisher of record, and links to every outlet that covered the event.

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?

Front-loads the usage trigger, then the return semantics, then the filtering summary and exclusion. Three sentences with little waste, though the publisher/outlet-links clause is descriptive padding that could be trimmed without loss.

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 carries the return shape and does so adequately: one story per event, newest first, sourced, with coverage links. All five optional parameters are schema-documented, cursor pagination is explained in the param, so nothing an agent needs to call this correctly is missing.

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%, so q, kind, limit, since and cursor are all fully documented in the schema itself. The description only adds a summarizing line ('Narrow by words, kind or date') that maps loosely to q/kind/since, giving baseline value without new syntax or format detail.

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+resource (list news) with a tightly scoped domain: aging research and longevity industry events, enumerating the covered categories (financings, trial readouts, approvals, policy, conferences). It also distinguishes itself from generic siblings by excluding general, political and market news, so an agent can tell it apart from list_stories/list_feed without opening the schemas.

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?

Opens with an explicit trigger ('Use this when the user asks about events in aging research and the longevity industry') and closes with a clear exclusion ('Only news of this field; not for general, political or market news'). It does not name specific alternative siblings for those excluded cases, so the routing guidance stops just short of fully explicit.

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