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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), and the description adds genuinely non-obvious behavior: an explicit price ($0.025), the fact that the call returns the x402 payment requirements and URL (i.e., a payment handshake before data), and that stale or absent data yields an error with no charge. That last point materially changes agent retry logic.

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 compact sentences, front-loaded with the price and the resource, followed by return content, error behavior, and the sample link — every element earns its place. It is slightly dense as a run-on chain of clauses, but there is no filler.

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 zero parameters and no output schema, the description must carry the return shape and payment mechanics itself, and it does: content fields, error/no-charge rule, and the x402 challenge response. Minor gaps remain around payment completion flow and data freshness/cadence, but an agent has enough to call it correctly.

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?

There are no parameters, so the baseline is 4; the description correctly implies the tool takes no input and describes the fixed window (seven days) rather than offering filters. Nothing about parameter semantics is left ambiguous.

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 names a specific resource and scope — weekly narratives pack, top multi-outlet story clusters from seven days of headline-tagger events, with titles, blurbs and links. That content profile (cross-outlet clustering over a 7-day window) is distinct enough from siblings like get_latest_brief or get_teaser that an agent can pick it 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 gives useful routing context: this is a paid call, a failed/stale-data call costs nothing, and a free sample URL exists at cryptofeed402.site/samples/narratives-weekly, which effectively names a zero-cost alternative. It does not explicitly state when to prefer this over siblings such as get_latest_brief or get_sample_brief, so it stops short of full when/when-not guidance.

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