list_variable_incomes

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

With readOnlyHint already set, the description adds valuable context beyond the annotation: it discloses that only a gross amount is returned, explains why (real spec publishes no net amount), and clarifies that taxes/fees are reported per-transaction. This goes beyond the annotation's simple read-only signal, though it does not discuss pagination, consent, or error behavior, preventing a 5.

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?

The description is well-structured with a clear opening sentence, a focused explanatory paragraph about net_amount, and labeled Args/Returns sections. Every sentence contributes meaning without redundancy, and the length is appropriate for the tool's complexity.

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?

The description fully covers the tool's purpose, output fields, key behavioral nuance (gross vs. net), and return aggregate. With an output schema present and readOnlyHint annotation, the description adds the necessary spec context and differentiators, making the tool's behavior clear and complete for an agent.

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 0%, so the description must compensate. It briefly explains subject_id as 'User's CPF' and bank as 'Participating bank', adding some meaning, but the bank explanation is generic and the enum already lists valid values. The description also mentions a 'ctx' arg that is not in the schema, which could confuse. Overall, partial compensation but with gaps.

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 explicitly states it 'Lists a user's variable income asset positions (stocks, ETFs, and other exchange-traded assets)' and specifies the data included: quantity, closing price, and gross amount. It also distinguishes this tool from siblings (list_investments, list_funds, list_treasure_titles) by noting the absence of net_amount, making its purpose clear and unique.

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?

The description provides clear when-not-to-use guidance by explicitly contrasting with siblings: 'unlike list_investments/list_funds/list_treasure_titles' and explaining the spec-based reason for the difference. It implies use cases (needing variable income positions) without explicitly stating 'use when...', so it earns a 4 rather than 5.

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