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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds one genuinely useful behavioral boundary (receivables only, never payables), but says nothing about result shape, ordering, counts, or whether the days window also affects overdue results.

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?

Two tight sentences: what it returns first, the exclusion second. No filler, no restatement of the title, and the scope statement is front-loaded.

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?

There is no output schema, so the description is the only place a caller could learn what a result row contains (debtor, amount, due date) — and it does not. For a simple two-optional-parameter read tool this is a modest gap rather than a blocking one.

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 100% and both parameters are documented there, including defaults ('vychozi 30', 'Vychozi overdue'), so the baseline of 3 applies. The description contributes nothing about how 'days' interacts with status=overdue, which is the one ambiguity worth clarifying.

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+resource (list issued invoices) plus scope: overdue or approaching due date, framed as 'who owes me'. It also explicitly excludes payables, so the agent knows this is receivables-only and cannot confuse it with a liabilities/cashflow query among the siblings.

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 negative routing is explicit: 'Zavazky k uhrade tento nastroj nevraci' tells the agent this is not the tool for payables. The status enum additionally encodes the overdue/upcoming/all modes, but the description never contrasts this tool with nearby siblings like get_cashflow or get_tax_deadlines.

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