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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower. The description still adds a genuinely non-obvious behavior: an unknown site_id returns an empty list rather than an error. It doesn't discuss pagination or result limits, keeping it short of a 5.

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 compact sentences with zero filler; the core purpose leads and the filter/edge-case clause follows. Every clause carries information.

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-optional-parameter read tool with rich annotations and no output schema, the description supplies the return contents (status, contact counts), the filtering behavior, and the error semantics. Nothing an agent needs to call it correctly 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?

Schema coverage is 100%, so the baseline is 3; the description adds meaning beyond the schema by clarifying that the filter is optional and defining the edge case for an unrecognized site_id (empty list, not an error). That is real semantic value, though it doesn't explain the id's origin (the schema does, via list_websites).

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 (List) and resource (this account's outreach campaigns) plus the fields returned (status and contact counts). It is clearly distinct from outreach_get_campaign by its plural listing scope, but it never names a sibling (e.g., zeekeo_list_campaigns) to disambiguate which listing tool to pick.

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?

Usage is implied by 'List ... campaigns' plus the optional filter note, but there is no explicit when-to-use guidance, no when-not, and no mention of alternative tools such as outreach_get_campaign or zeekeo_list_campaigns. Adequate but leaves the agent to infer routing.

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