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

readOnlyHint=true already establishes this as a safe read, so the description's burden is lower. It adds only the REST endpoint mapping and says nothing about pagination defaults, result ordering, or what happens when organization_id is omitted on a multi-org token.

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?

A single tight sentence front-loads the core action and filters. The trailing 'Polar: GET /v1/customers/.' endpoint mapping is slightly redundant for an agent but costs little.

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 simple, no-required-param, read-only list tool with no output schema, the essentials are covered. However, the multi-org caveat on organization_id (documented only in the schema) and pagination behavior are not surfaced, leaving gaps an agent may hit at call time.

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% with each of the five parameters documented, so the baseline is 3. The description echoes email and query but adds no semantics for page, limit, or organization_id beyond what the schema already says.

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 ('List customers') and its optional narrowing (email or text query), which is enough to distinguish it from the singular polar_get_customer sibling. It does not explicitly name that sibling, so differentiation is implicit rather than stated.

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 phrase 'optionally by email or a text query' implies when to use which filter, but there is no explicit guidance on when to prefer this list tool over polar_get_customer or polar_get_customer_state, nor any prerequisite (e.g. organization_id when the token spans orgs).

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