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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, but the description adds material behavior the annotations cannot convey: no account numbers, masks, or credentials are returned, and property accounts appear regardless of the net-worth toggle with in_net_worth signalling the current state. It also defines the empty:true contract and the next_step_url follow-up, which is exactly the kind of non-obvious behavior an agent needs.

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?

Front-loads what the tool returns, then layers the genuinely non-obvious caveats (property valuation, net-worth toggle, empty result handling). Every sentence is substantive, though the property-valuation explanation is dense and slightly longer than strictly necessary.

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 carries the full burden of explaining return contents, and it does: field list, the special property case, the privacy exclusion of account numbers/credentials, and the empty-result protocol. An agent can call this and correctly interpret both populated and empty responses.

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?

There is one optional parameter with 100% schema description coverage, so the schema already documents `month` as 'YYYY-MM, optional'. The description never references the month parameter at all, adding no extra semantics, but per the high-coverage baseline a 3 is appropriate since the schema carries this load.

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 and resource ('Lists the user's accounts') and enumerates the returned fields: category, currency, balance (original + base), and net-worth inclusion. It is clearly distinguishable from siblings like get_net_worth and get_balance_history, which cover aggregate and historical views rather than the account roster.

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 operational guidance: when in_net_worth is false you can offer to include the property account, and when empty:true you should relay the message and next_step_url instead of treating it as an error. It stops short of explicitly contrasting when to call this versus get_net_worth or get_balance_history, so it is clear context without full alternative routing.

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