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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds the returned field set, but says nothing about pagination behavior, rate limits (though the schema's limit param covers this), or result ordering beyond what annotations provide.

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 with no filler, and the field enumeration is front-loaded. The 'expense.get' fragment is slightly cryptic but otherwise efficient.

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 list tool with annotations covering safety and no output schema, enumerating returned fields is valuable and mostly complete. The main gap is the absence of guidance on pagination or how the various date parameters relate, though the schema partially compensates.

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?

With 75% schema description coverage, the baseline is 3. The description names invoice number and date-range filtering, which maps to some params, but does not clarify the distinction between start/end_date and start/end_paid_date, nor the meaning of invoice_id, leaving semantic gaps the schema doesn't fill.

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 expense entries') and enumerates the returnable fields (supplier, category, net/VAT/gross, dates, document URL), which is concrete. However, it does not differentiate itself from sibling list tools like list_revenues or list_invoices beyond the resource name.

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?

Mentions filtering by invoice number or date ranges, implying usage, but provides no explicit when-to-use guidance, prerequisites, or alternatives to the other list_ tools. Usage must be inferred from the filter options.

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