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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely useful content-shape context — payouts, conditions in the bank's own words, eligibility exclusions, and a last-checked timestamp — but says nothing about ordering, pagination, or whether stale/expired offers appear.

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?

One dense, front-loaded sentence that leads with scope and then enumerates the returned content. The phrasing "what Pocketly counts" and "who can’t get it" is colloquial but compact; nothing is wasted.

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 is the only source for return content and it does a decent job of naming the returned facets. However, for a list tool it omits ordering, result-size/pagination behavior, and whether non-live offers are excluded, leaving gaps an agent needs when consuming results.

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% and the single optional enum parameter (kind: switch/premier/joining) is fully documented in the schema. The description never mentions the kind filter and its phrase "Every live ... offer" could briefly suggest there is no filtering, but the schema corrects this, so baseline 3 applies.

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 resource with clear scope: "Every live UK current-account switching offer Pocketly holds" tells the agent this is an enumerating read over active switching offers only. It does not explicitly differentiate itself from siblings like get_offer or check_offers, so the agent must infer the list-vs-single distinction from the name.

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?

The description never says when to use this tool rather than check_offers, get_offer, or list_changes, nor does it state any exclusions or prerequisites. The only hint is "Every live ... offer", which weakly implies bulk enumeration, but the agent is left to infer routing from sibling names.

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