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 genuinely new behavior: a 6-hour refresh cadence and the hard limitation that only metadata is returned ("never article text"), which prevents the agent from expecting content to summarize.

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 short sentences, front-loaded with what the agent gets, followed by the returned fields, the freshness guarantee, and the scope limitation. Nothing is redundant with the title and every sentence adds 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 correctly carries the return-value burden by enumerating the four fields and ruling out article text, and all three parameters are fully covered by the schema. Only minor gaps remain, such as how ordering works when limit is capped at 100.

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 limit, category and visitor_name are already documented, and the description adds no syntax or default detail beyond them. The only faint addition is the source-type list loosely mapping to the lab/research/news/tools enum, so the documented baseline of 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?

Specific verb ("Get up-to-date headlines") plus a precise resource (AI headlines aggregated from labs, research feeds, news sites, developer blogs), and it names the four returned fields. It is clearly distinguishable from siblings like top_repos or list_live_sources, though it never names an alternative explicitly.

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?

Usage is implied rather than stated: it tells the agent this is a headline feed and to "Read the source for details," which is a when-to-go-elsewhere hint. There is no explicit statement of when to choose this over a sibling such as whats_new, list_live_sources, or top_repos.

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