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

Annotations already cover read-only and closed-world, so the bar is lower; the description still adds the ranking behavior (highest-velocity-first, ties preserve feed order) and the no-auth fact. It does not mention rate limits or pagination, but for a bounded top-N feed that matters less.

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 what is returned and how it is ranked before the field enumeration and args. The parenthetical field list (dek, beat, date, publishedAt, image, focal) is useful since there is no output schema, though it makes the sentence dense.

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 enumerating returned fields, stating sort order, tie-breaking, and auth requirements. An agent has everything needed to call and interpret the result.

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 all three parameters are already documented in the schema. The inline Args block largely restates ranges, defaults, and even the substring-over-title-and-summary definition, adding little beyond the schema — baseline 3.

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 (velocity-ranked AI news) and immediately contrasts itself with the ic_signal_* family, calling out THE SIGNAL weekly dispatch as a different surface. An agent can distinguish this tool from its siblings without opening any schema.

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 names the closest alternative family (ic_signal_*) and characterizes what that serves versus this raw aggregator firehose, which effectively routes the agent. It stops short of an explicit 'use this when / not when' rule, but the context is clear.

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