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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds genuine behavioral context beyond that: fixed page size of 25 and the underlying GET /customers.api endpoint, which helps an agent reason about pagination cost and caching. It stops short of describing error behavior for malformed filter_val or what a customer record contains.

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?

Front-loaded with the core action and page size, then the filtering rules — two dense clauses with no filler. Minor waste in re-listing all ten filter names that the schema enum already carries.

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, zero-required-parameter list tool with no output schema and fully documented params, this covers what an agent needs to make a correct call. The remaining gap is the failure mode when a valueless filter is passed, which matters for correct invocation.

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 coverage is 100%, so the individual parameter meanings are already documented and baseline would be 3. The description earns above baseline by stating the cross-parameter constraint the schema never encodes: email, category, account_name and completed_orders require filter_val, including the "> 50" comparison syntax. It slightly duplicates the enum list that the schema already enumerates.

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 customers") plus the page size and the filterable surface, so an agent knows exactly what it retrieves. It never names the sibling it is not — get_customer (single record) or search_member_by_email — so the boundary is left implicit.

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?

"Optional filter" plus the list of permitted filter names and which of them require filter_val gives real guidance on how to drive the tool. However there is no when-to-use/when-not guidance relative to get_customer or search_member_by_email, and no statement of what happens if filter is supplied without filter_val.

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