Find subscribers by exact email

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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the meaningful behavioral fact that this is a compatibility alias rather than a primary tool. It does not describe pagination behavior, though the schema covers all_pages/max_items.

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, front-loaded sentence with no filler; the required filter is stated up front and nothing is redundant.

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 17-parameter tool with 18% schema description coverage and no output schema, a one-line description is inadequate. Annotations cover the safety profile, but an agent still lacks guidance on the many filter, sort, and pagination parameters. The definition is under-specified relative to the tool's complexity.

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 only 18% (3 of 17 params documented), so the description carries a heavy burden it does not meet. It adds one useful semantic detail — that email_address is an 'exact' match — but leaves the other 14 parameters, including the status/sort enums and pagination controls, unexplained. It compensates only marginally for the coverage gap.

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 names a specific verb (search/find), resource (subscribers), and scope (required exact email_address filter), and explicitly identifies the sibling it aliases (list_subscribers). An agent can tell what it does and how it differs from list_subscribers. The 'compatibility alias' framing slightly muddies whether it is a distinct capability or a legacy shim, keeping it from a 5.

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?

Calling it a 'compatibility alias for list_subscribers' implies it exists for backward compatibility and that list_subscribers is the preferred tool, but this is left implicit. There is no explicit when-to-use/when-not guidance or statement of which alternative to prefer for new work.

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