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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds behavioral context beyond that: 'Free, no auth' (auth requirement), 'newest first' (ordering), 'at most 40 items' (pagination/limit), and the output fields (title, date, URL, one-line why). These are not in annotations and are genuinely useful for invocation.

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 sentences plus a JSON example, with no filler. The core purpose and scope are front-loaded, the example is compact, and the alternative tool is mentioned at the end without bloating the text. Every sentence earns its place.

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?

There is no output schema, but the description explicitly lists the returned fields (title, date, URL, one-line why) and the maximum count. Parameters are fully documented in the schema, the safety profile is in annotations, and the alternative tool is named. Nothing an agent needs to call this tool 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 coverage is 100%, so the baseline is 3. The description adds a concrete JSON example that demonstrates how to use both parameters together, and clarifies that 'kinds' is optional with a default of all. The example adds value beyond the schema's field-level descriptions, so a 4 is justified.

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 states a specific verb ('quick feed'), a resource ('New Runtime published items'), a time window (1-14 days), content types, ordering, and a limit (40 items). It also names the sibling it is not (what_changed) and the condition that selects it, so an agent can disambiguate at a glance.

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 explicitly says 'Use for a quick feed' and then directs the agent to the alternative: 'For what changed against what you already knew, use what_changed.' This gives both a when-to-use and a when-not-to-use, plus the sibling name.

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