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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the full safety profile is covered by structured data. The description adds the useful framing that the output is raw numbers for reasoning rather than a rendered view, but discloses nothing about pagination, rate limits, or permission requirements. Moderate added value against a strong annotation set.

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 short sentences with zero filler; the domain statement is front-loaded and the routing hint follows immediately. Every clause earns its place.

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 return values need no explanation, and annotations cover the safety profile, leaving little for the description to carry. The remaining minor gap is that the status filter's behavior (active vs all) is never surfaced in prose, but for a zero-required-parameter read tool this is close to complete.

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?

The single status parameter has 100% schema description coverage including an enum and a default of "active", so the schema fully documents it. The description never mentions status or the active/all distinction, adding no meaning beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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?

"Recurring-charge detection" states the resource/domain clearly, and combined with the get_subscriptions name an agent understands it retrieves subscription data. It also implicitly distinguishes itself from the sibling "subscriptions" card, though it never uses an explicit verb like "returns" or "lists".

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?

"Numbers to reason with — to display, use the subscriptions card" explicitly routes the agent between this data tool and the display sibling, which is exactly the kind of alternative-selection guidance that matters here. It stops short of an explicit when-not for the status filter or for adjacent siblings like get_transactions.

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