Overview — Available tools

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

Annotations already declare readOnlyHint=true, so safety is covered; the description goes beyond them by disclosing that the response carries conventions such as how amounts are expressed, which reads cost a request per month, and hidden categories. That is genuinely useful pre-call context, though return shape details are left to the output schema.

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 the [READ] marker and the primary action, then the routing advice, then the extra payload. Efficient, though the middle and last sentences could be tightened slightly.

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 values need not be enumerated, and the description supplies the routing rationale and the notable extra content the overview returns. Complete enough for an agent to decide to call it first, with only minor room for detail.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline for a no-param tool is 4. No param-level value could be added here.

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 ('List all available tools grouped by family, with classification and summary') and its scope is unambiguous. As the meta/overview tool it is inherently differentiated from every domain sibling like payees_get or transactions_list.

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?

Explicitly directs the agent: 'Start here to understand what the server can do before running other tools.' That is clear when-to-use guidance, though it gives no when-not condition or named alternative (the schema itself has no competing sibling).

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