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

readOnlyHint=true already establishes this is a safe read. The description adds that results carry balances and contacts, which is useful context beyond the annotation, but says nothing about default page size, sorting defaults, or the shape of the paginated response.

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, front-loading the resource and returned fields before the filter options. The trailing API endpoint reference is slightly redundant but harmless and aids traceability.

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 usefully names what each record contains (balances, contacts) so the agent knows the return payload. Missing only pagination and ordering defaults for a nine-parameter list tool.

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%, so all nine parameters are already documented in the schema with examples (e.g. 'balance' operator syntax, per_page range). The description only echoes name/email/number search, adding nothing beyond the structured data; baseline 3 is correct.

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 (List) and resource (clients) and names the fields returned plus the three searchable dimensions. It clearly separates itself from create/update/get_client in intent, though it doesn't explicitly state the difference from get_client.

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 phrase 'optionally searched by name, email or number' implies when the filters apply, but there is no explicit guidance on when to use this over invoiceninja_get_client for a single lookup, nor any mention of pagination limits or rate limits.

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