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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds real value beyond that: ordering guarantee, the distinction between published_at (site publication time) and date (announcement date), and the content caveat that these are announcements rather than offers. It omits pagination behavior across the limit/offset range and any rate-limit notes.

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 the core action and ordering, then adds the filter and the semantic caveat in two short sentences; nothing is padding. The first sentence is dense with a parenthetical field-semantics clause, which is justified but slightly cramped.

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?

An output schema exists, so the description need not spell out return values, and the annotation set covers the safety profile. What remains thin is pagination guidance for limit/offset and any indication of result-set size or total counts, but overall an agent has enough to call this 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?

Schema coverage is 33%: only 'brand' is documented, and the description's 'optional exact brand, slug or alias filter' largely mirrors that. The limit and offset parameters have no description in either the schema or the description, so default/max behavior and pagination semantics must be inferred from the schema constraints alone.

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 ('List the latest Exchange.news stories') plus ordering ('newest published first') and the fields returned. None of the siblings (get_code, list_brands, list_campaigns, search_codes) touch news, and the description makes the resource unambiguous.

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?

Gives a clear boundary: 'Stories report official announcements; they are not offers or eligibility checks,' which steers the agent away from using this for offer/eligibility queries. It also frames the brand filter as optional exact matching. It does not name a sibling alternative for related lookups (e.g., list_brands), so it stops short of full when/when-not/alternative guidance.

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