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

readOnlyHint already conveys the read-only nature; the description reinforces it with the GET method and endpoint path. It adds no further behavioral detail such as response shape or empty-attribute behavior, but annotations carry the main burden here.

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 sentences, with the core action first and the endpoint as a concise reference. No filler or redundancy.

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-only GET with no output schema, the description plus schema fully cover what is needed to call it: resource, endpoint, identifier semantics, and safety. Nothing critical is missing.

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?

Input schema covers 100% of the one parameter, including identifier alternatives (id, cio_id, email), so the description need not restate it. The endpoint path indirectly confirms customer_id placement but adds no new semantic meaning.

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 the resource precisely: a single person's attributes/profile fields, via a GET to the customers attributes endpoint. This differentiates it from siblings like customerio_get_customer_messages and customerio_get_customer_segments by resource type.

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 description implies the appropriate use case: retrieving profile fields for one person, which is distinct from messages or segments. It does not explicitly name alternatives or exclusions, but the 'attributes/profile fields' scoping provides clear enough context for this simple tool.

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