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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real context: the default date semantics and the exact measures each report returns, but says nothing about volume, pagination or whether historical re-runs are stable. The duplicated 'Free. Free.' is redundant rather than informative.

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 two-mode structure is reasonable and the aging buckets are front-loaded, but the prose is a dense run-on and the trailing 'Free. Free.' is a duplicated, wasted sentence.

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 report tool with no output schema, the description enumerates the returned measures (current/1-30/31-60/61-90/90+, net, tax, total, paid) and the grouping keys, which is what an agent needs to pick the right report. Only the display/pagination mechanics are left unstated.

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 description meaningfully extends the 75%-covered schema: it states that as_of defaults to today, that from/to are keyed on issue date and default to the current month, and it decodes the report enum into concrete semantics. That is the kind of meaning the enum and pattern fields cannot carry.

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?

Names both modes explicitly and describes the exact content of each: aged_receivables gives per-customer amounts bucketed by days past due and currency; sales gives invoiced/net/tax/total/paid per customer. This is specific verb+resource work, though it never distinguishes itself from near neighbours such as invoices_summary or invoices_statement.

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?

Usage is only implied by the two report branches and their stated defaults (as_of = today, from-to = this month). The one routing hint, 'To show a person, put it in a view (view_show)', is a follow-up step rather than guidance on when this report beats the sibling reports.

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