list_accounts

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

The readOnlyHint annotation already discloses the read-only nature. The description adds a bit of context ('participating in Open Finance Brasil' and 'all bank accounts'), but it does not disclose additional behaviors such as consent requirements, error conditions, pagination, or what happens if the user has no accounts. With annotations present, the bar is lower, yet the description adds limited behavioral nuance.

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 concise first line followed by Args and Returns sections. It is not overly long, though the Returns line somewhat repeats the first line. The extra 'ctx' parameter could be seen as unnecessary detail, but overall it is efficient and easy to parse.

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?

For a read-only listing tool with an output schema and readOnlyHint annotation, the description covers the core purpose and parameters. It does not mention consent prerequisites or error handling, but these are not critical for a simple list operation. The tool's role among siblings is clear enough, though explicit usage guidance would improve completeness.

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?

The input schema has zero description coverage, so the description carries the full burden. It provides useful meaning for the two schema parameters: subject_id ('User's CPF (digits only) or internal ID') and bank ('Identifier of the participating bank'). However, it also lists a 'ctx' parameter not present in the input schema, which could mislead agents into thinking it must be passed as an argument.

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 clearly states the tool's function with a specific verb ('Lists') and resource ('all bank accounts'), and includes account types (checking, savings, prepaid), distinguishing it from sibling tools like get_balance or list_transactions. The scope ('of a user at an institution participating in Open Finance Brasil') adds clarity.

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 implies when to use the tool (to retrieve all accounts for a user at a bank), but it does not explicitly mention alternatives or exclusions. It does not state 'use this instead of get_balance' or provide when-not-to-use guidance, which would help an agent choose appropriately among sibling tools.

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