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

Annotations already declare readOnlyHint=true, so the description is not needed for safety. It nevertheless adds real context the annotations don't: the underlying endpoint (POST /v2/view_customer_profile) and, more importantly, the payload contents, which matters because there is no output schema.

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 short fragments with the resource front-loaded and no filler. The endpoint string is arguably noise but is defensible as a traceability aid; the phrasing is telegraphic rather than a complete sentence.

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 one-parameter read tool with no output schema, the description does the important extra work of enumerating what comes back (contact details, address, coordinates). Missing only routing guidance versus the phone-lookup and list siblings.

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 100% schema description coverage and a single required integer parameter that even cites its provenance (tookan_list_customers), the schema carries the semantics. The description adds nothing about the id format or constraints, so the 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 resource and scope: a single customer's profile, with the fields returned (contact details, address, coordinates) named explicitly. It is distinguishable from tookan_list_customers by the singular 'one customer', though it never names that sibling directly.

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?

No when-to-use or when-not-to-use guidance appears in the description. The nearest alternatives, tookan_find_customer_by_phone and tookan_list_customers, are never referenced, and the only hint (customer_id 'from tookan_list_customers') lives in the schema rather than the description.

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