Find subscriptions and recurring payments

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

Annotations already declare this a safe, idempotent, non-destructive read, so the description's job is to add operational context, and it does: it discloses what is scanned (outgoing transactions only), the default lookback, the sort order (annual cost), and the derived fields returned, including an activity heuristic. It falls short of explaining how 'still looks active' is determined or any heuristic limits.

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?

A single, front-loaded sentence with the scope and default stated before the return-value list; nothing is padded. The trailing list of returned fields is dense but each item is informative, so no sentence 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 correctly carries the burden of describing returns (cadence, amounts, next expected date, annual cost, sort order) and scope defaults. Combined with complete annotation coverage and a fully documented parameter schema, an agent has what it needs; only the definition of the activity heuristic is left unclear.

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%, so the schema already documents all six parameters including defaults and the minOccurrences bounds. The description only restates the value of the active filter and the 12-month default window, adding no new parameter semantics; 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 description names a specific verb and resource ('scans outgoing transactions ... for payments that repeat on a regular cadence') and enumerates what qualifies: subscriptions, direct debits, standing orders, memberships. It further distinguishes itself from the list_* siblings by stating it returns derived values (cadence, next expected date, estimated annual cost), making it obviously an analytical detection tool rather than a mandate/order listing call.

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?

Usage is implied by the capability description (use this to discover recurring outgoings), and the description states the default window of the last 12 months plus the activeOnly toggle. But it never says when to prefer this over list_standing_orders or list_direct_debit_payments, nor any exclusions or prerequisites, so the guidance stays implicit.

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