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

With readOnlyHint and destructiveHint already true/false, the description adds useful behavioral context: results are authorization-scoped ('authorized') and field-bounded with addresses and notes explicitly excluded. This tells the agent what data it can expect without contradicting the annotations.

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?

The description is a single dense sentence that front-loads the core behavior first and appends the key exclusions. There is no filler or repetition of the title/schema.

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?

The description is adequate for a simple one-parameter read tool, but it leaves gaps: it does not enumerate which contact/lifecycle fields are returned, and the schema marks customer_id as not required, creating ambiguity about whether the tool can be called without an ID. With no output schema, those details matter.

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% because the only parameter is already documented as the customer ID returned by search-customers. The tool description itself adds no further parameter semantics beyond the singular 'one customer' cardinality, so the baseline of 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?

The description states a specific operation (returns one customer) with a clear resource and a bounded field scope: 'bounded contact and lifecycle fields; addresses and notes are excluded.' This distinguishes it from sibling search/list tools and from other get-* resources.

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?

The intended usage is only implied: a single customer lookup by ID, with the ID source given in the schema ('Customer ID returned by search-customers'). The description does not explicitly say when to prefer this over search-customers or other sibling tools, nor does it spell out exclusions.

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