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

Annotations already declare readOnly/no-destructive, so the safety bar is low; the description goes further by stating the auth requirement ('Cotlet API key with access to this app') and detailing the returned content types. It does not mention rate limits or pagination, but adds solid context beyond 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 first sentence fragment and the second sentence restate nearly the same list (notes, active subscriptions/packs, upcoming bookings), which is redundant. It is front-loaded and short, but the duplication costs it efficiency.

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?

Because there is no output schema, describing the returned fields is valuable and it does so. Combined with the auth note and upstream/downstream routing hints, it covers what an agent needs to invoke and interpret a read-only fetch correctly, with minor gaps on error/empty behavior.

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 schema itself explains customer_id ('Customer ID from search_customers'), so the description doesn't need to. The description adds no additional parameter semantics beyond what the schema provides, matching the baseline 3.

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 a specific verb+resource (get one customer profile) and enumerates the payload: profile, tags, notes, subscriptions/packs, and upcoming bookings. It clearly reads as a single-record fetch, implicitly distinct from search_customers, though it never names an alternative explicitly.

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?

Notes that subscription IDs feed freeze_membership and cancel_membership_renewal, which gives some downstream context, and states the API-key prerequisite. However, it never says when to call this versus search_customers or list_customer_payments, so usage is only implied.

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