get_register_payments_summary

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

Annotations already declare readOnly, idempotent, non-destructive, and openWorld, so the safety profile is covered. The description adds one genuinely useful behavioral fact: it reports on the register's current or last session rather than an arbitrary date range, which explains why there is no date parameter. It does not clarify what happens when no session exists or whether amounts are net of refunds.

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?

One compact sentence with the resource front-loaded and zero filler. It is efficient, though the 'current/last' phrasing packs ambiguity into very few words rather than resolving it.

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 single-parameter read tool with full annotations and an output schema, the description covers the core idea and the session scoping, so it is broadly sufficient. It still leaves the register_id semantics and the current-versus-last distinction unexplained, which matters when the tool has no date-range parameter.

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% and the only parameter, register_id, is never described in the description beyond the possessive phrase 'a register's'. No format, source, or lookup guidance is given, so the description does not compensate for the undocumented schema.

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 names a specific resource (payment totals broken out by payment type) and a scope (a register's current/last session), so the agent can infer it returns an aggregated breakdown rather than raw payments. However, there is no verb and no differentiation from nearby siblings such as sales_summary, get_user_sale_totals, or list_payment_types. It is adequately specific but leaves the agent guessing how it differs from other summary tools.

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?

There is no statement of when to use this tool versus sales_summary, get_user_sale_totals, or list_payment_types, and no prerequisites or exclusions. The agent must infer usage from the name and the one-line summary alone.

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