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 adds a genuinely useful non-annotation detail, the master-API-key authentication requirement. It still does not describe pagination behaviour or result limits, which the annotations do not cover either.

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 front-loaded sentences with zero filler; purpose comes first, then the auth prerequisite. The injected pricing block is boilerplate noise relative to tool selection but does not bury the operative 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?

With an output schema, full parameter coverage in the schema, and annotations carrying the safety profile, the description needs only purpose and prerequisites, both of which it supplies. A note on paging across the page/per_page pair is the only obvious missing piece.

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 100% for all three parameters (page, q_name, per_page), so the schema already carries the semantics. The description adds no syntax, defaults, or guidance about paging or keyword matching, so baseline 3 applies.

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 (Search) and resource (sequences / emailer campaigns), and resolves the naming ambiguity created by the 'post_' prefix by making clear this is a read-style lookup. It does not name a sibling to differentiate from, though the parenthetical alias quietly separates it from get_apollo_emailer_messages_search.

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?

"In your Apollo account" plus "Requires a master API key" gives the prerequisite and a general context, but there is no explicit when-to-use guidance or named alternative for searching messages rather than sequences. The agent must infer the boundary from the resource name alone.

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