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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description adds that no auth is required and specifies ranking behavior (highest-velocity-first, ties preserve feed order). It stops short of error/rate-limit behavior, but the added context is meaningful.

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-loaded with purpose and the sibling distinction, then return fields, then a compact Args block. Dense but nearly every clause carries information; only minor tightening possible.

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 enumerates return fields (url, velocity, summary, dek, beat, date, publishedAt, image, focal) and the ranking order, so an agent knows exactly what to expect. Nothing needed to call it 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 0%, and the description fully compensates: limit (1-25, default 20), min_velocity (>=1, default 1, explained as corroboration by >= N sources), and q (2-80 chars, case-insensitive substring over title + summary). Every parameter's meaning and constraint is documented.

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 and resource ('Returns newagg's velocity-ranked AI news') and explicitly distinguishes itself from the ic_signal_* surface. An agent can route to the correct tool without opening a 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?

Explicitly names the alternative surface ('a DIFFERENT surface from ic_signal_* which serves THE SIGNAL, the weekly editorial dispatch') and the condition that separates them: raw aggregator firehose vs curated editorial dispatch. Clear when-to-use routing.

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