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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and openWorldHint=false, so the safety profile is covered. The description adds only the notion that results are raw 'numbers to reason with' rather than presentational, with no detail on scope, freshness, or coverage.

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 clauses, purpose front-loaded before the display caveat, with no filler. It is arguably under-specified rather than padded, so conciseness is good but not exemplary.

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 an output schema present and a 100%-covered single-parameter input, the description needn't explain returns or params. It adequately covers purpose and the display alternative, leaving only minor gaps about scope of detection.

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 description coverage is 100% and the single 'status' enum is self-explanatory with a default. The description adds nothing about what 'active' versus 'all' means, so the 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?

The phrase 'Recurring-charge detection' states what the tool produces, and combined with the name get_subscriptions the verb+resource is clear. It also implicitly separates itself from the display-oriented sibling ('subscriptions' card), though it does not name the other data siblings.

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 an explicit when-not and alternative: for display, use the subscriptions card rather than this tool. That routing is valuable, but it offers no guidance relative to the other data siblings like get_spending_breakdown or get_transactions.

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