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 nothing behavioral beyond that — 'SOAP GetCustomerByEmail' is implementation trivia, and it omits what happens when no customer matches or how many results come back.

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, nothing bloated, and the matching criterion comes first. However 'SOAP GetCustomerByEmail' spends one of only two sentences on plumbing detail rather than on information an agent can act on.

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?

With no output schema and no annotations describing return content, the description should say what a successful match returns (a customer object? an ID?) and how a miss is signalled. For an open-world lookup whose main risk is a silent no-match, that omission is significant.

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?

There is a single parameter with 100% schema description coverage ('The customer's e-mail address'), which sets the baseline at 3. The description reinforces that matching is on the email field but adds no format, normalization, or case-sensitivity 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?

The phrase 'The customer whose e-mail address matches' identifies the resource and the lookup key, but it is a noun fragment with no verb, so the action (look up / return a customer) must be inferred from the tool name. It also does not distinguish this from the many sibling customer lookups (kashflow_get_customer, kashflow_get_customer_by_id, kashflow_list_customers).

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?

There is no guidance on when to use an email lookup versus kashflow_get_customer_by_id or kashflow_list_customers. The only implied usage comes from the tool name and the word 'e-mail', which is already in the schema.

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