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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description adds substantial behavior: primary/mentioned labelling, the ticker-as-English-word false-match caveat (ON, IT), withheld redirect URLs, no sentiment generation, the paid x402 cost of $0.003 per call including the first, and the no-charge refusal on empty results.

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?

Purpose and scope lead the text, and most sentences carry distinct information. It loses a point for redundancy: the paid-only status appears twice ('Paid-only, including the first call' and 'Hosted access: paid-only; each call costs $0.003'), which could be one sentence.

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 takes on the return-value burden and does so adequately: it names the returned fields, the labelling scheme, the refusal case, and the withheld redirect URLs. Nothing an agent needs to call this 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, but the description adds real semantic meaning for `ticker` — it warns that a legitimate ticker that is also an English word can match an unrelated upper-case headline — and reinforces the `x_payment` retry flow with the cost amount.

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 — read licensed Finnhub company headlines for a ticker over the trailing seven days — and enumerates the returned fields (publication time, source, summary). This clearly separates it from sibling news tools like otto_crypto_news and otto_news_recaps.

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?

Sets boundaries well: 'News context only; not a recommendation', paid-only on every call, and a defined empty-result path (`no_recent_news`, nothing charged). It does not explicitly route the agent to or away from specific siblings (e.g. otto_news_recaps, otto_equity_intel), 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.