List accounts

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

Annotations already declare readOnly/idempotent/openWorld, and the description adds genuine behavioral context beyond them: balances are in currency units, and a broken bank link means no transactions will arrive until fixed in YNAB. It doesn't cover pagination or volume, but the diagnosis nuance is substantive.

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?

Three sentences, front-loaded with what is listed, then the use cases. The parenthetical about broken bank links is long but earns its place by explaining an actionable failure mode; nothing is padded.

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 structure needn't be described, and the single required parameter is fully specified. Combined with the usage and behavioral notes, an agent has what it needs to call this correctly, with only minor gaps (freshness, volume).

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%, so plan_id (including the 'last-used' sentinel) is already fully documented. The description adds nothing about the parameter, so the baseline 3 applies when the schema does all the work.

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+resource ("List the plan's accounts") and enumerates the payload it returns: balances, bank link, last reconciliation. This clearly separates it from siblings like list_category_groups or find_transactions, though it never names an alternative explicitly.

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 concrete triggering scenarios: reconciling YNAB with the bank, detecting a broken bank link, and flagging accounts unreconciled for months. That is clear when-to-use context, but it offers no when-not or named alternative for account-related queries.

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