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 useful context about which fields are returned by default versus deferred (field_values, credit_balance, staff_assignments reachable via expand), but offers nothing on auth, rate limits, or error behavior.

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-loaded with the verb and resource, followed by the expand hint and the underlying endpoint. No filler, though the trailing 'TeamUp: GET /customers/{id}' is marginally redundant with the tool name.

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 single-resource fetch with annotation coverage, a fully described param schema, and no output schema, the definition is nearly complete. Enumerating the default returned fields compensates for the missing output schema, leaving only error/not-found behavior unaddressed.

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 three parameters are already documented; baseline is 3. The description adds marginal value by naming concrete expand targets (field_values, credit_balance, staff_assignments) as deferred fields, but no syntax or format details beyond the schema.

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?

Specific verb (Fetch) plus resource scope (one customer by id), and it enumerates the key returned fields (name, email, family role, lead flag, CRM status, created date). It is clearly distinguishable from the sibling goteamup_list_customers (one vs many).

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?

It gives a conditional instruction for 'expand' to retrieve deferred fields, which is useful actionable guidance. However, it never states when to prefer this tool over goteamup_list_customers or goteamup_get_customer_membership, so the alternative-selection guidance is only implied.

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