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

readOnlyHint=true already declares this as a safe read, so the bar is lower. The description adds the returned field set and the upstream endpoint mapping (GET /customers), but says nothing about pagination behavior, result caps, or ordering defaults beyond what the schema covers.

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 zero filler, leading with the core action and result contents before the search semantics and endpoint reference.

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 full schema coverage and no output schema, the description covers purpose, search scope, and returned fields adequately. It could mention pagination defaults or result ordering, but nothing essential is missing.

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 seven parameters are already documented, including the q search scope and location_ids note. The description repeats the q scope rather than adding format, default, or interaction detail, so baseline 3 applies.

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 or search') and resource ('customers'), and adds what the results contain (phone numbers, tags, addresses). It does not explicitly distinguish itself from the sibling housecall_get_customer, so it stops short of a 5.

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?

Usage is implied by 'List or search' versus the singular get_customer sibling, but the description never states when to use this tool versus that one, nor any exclusions. The q-search sentence is parameter guidance rather than routing guidance.

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