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 the useful output concept (unpaid invoices bucketed by days past due), which matters because there is no output schema, but says nothing about filters, scope, or result size.

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 short defining clause followed by three compact trigger phrases; nothing is padded and the purpose arrives first.

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 parameterless read-only tool with no output schema, the description supplies an adequate picture of what comes back (unpaid invoices plus days past due). The only real gap is the unresolved overlap with get_ar_aging.

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 the baseline expectation is 4. The schema is trivially complete and there are no parameter semantics for the description to clarify.

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 resource and what it returns: 'unpaid invoices with how many days past due'. That is clearer than a bare name restatement, but it does not distinguish itself from the near-identical sibling 'get_ar_aging', which an agent could easily pick instead.

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?

Provides trigger phrases ('AR aging', 'overdue invoices', 'who owes us') that imply when to use it, but gives no exclusions and never mentions alternatives such as get_ar_aging or find_invoices for related invoice lookups.

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