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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds only the underlying route (GET /users/{user_id}), which confirms the read nature but adds no new behavioral context such as not-found handling or auth requirements.

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 no filler; the resource and returned fields are front-loaded. Slightly telegraphic, but nothing is wasted.

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 single-parameter read tool with no output schema, listing the returned fields (email, registration date, billing/delivery address) fills the gap the missing output schema would leave. Not-found behavior and any auth notes are the only omissions.

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% and the single customer_id parameter is documented with type, bounds and a description, so the schema carries the burden. The description adds nothing beyond that, which is the baseline case.

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?

"One customer" names a singular resource fetch and enumerates the key fields returned, which distinguishes it implicitly from the sibling sellasist_list_customers. It never names the sibling explicitly, so the differentiation depends on the reader inferring singular-vs-list.

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?

"One customer" implies this is the by-ID lookup versus the list tool, but the description states no explicit when-to-use condition, no prerequisites, and does not name sellasist_list_customers as the alternative for browsing.

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