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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds useful context on matching behavior (partial, bilingual) and the empty-query default, but says nothing about result ordering, pagination, or what happens when there are no matches.

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?

Three tight sentences with the core action and matching rules front-loaded, followed by return fields and the empty-query fallback. No filler or restated title text.

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?

With no output schema, the description correctly enumerates the returned fields (invoice count, total billed, unpaid amount, last invoice date), which is exactly the missing piece. The only real gap is the undocumented `limit` parameter for controlling result size.

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%, so the description must carry the parameter burden. It explains `query` well (name, Arabic/English, partial match, empty means top customers) but never mentions `limit`, whose default of 10 and cap of 50 are only visible in the schema's raw constraints.

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 ('Search the user's past customers by name') plus the matching semantics (Arabic or English, partial match) and what is returned. None of the siblings (create_invoice_draft, list_unpaid_invoices, sales_report) do customer lookup, so an agent can route here without ambiguity.

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?

Gives a concrete usage condition: 'Leave query empty to list top customers', which tells the agent how to fall back to a listing behavior. It does not explicitly exclude cases where list_unpaid_invoices or sales_report would be the better choice, so it stops short of full when-not guidance.

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