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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered structurally. The description adds genuinely useful context beyond that: the master API key requirement and per-request pricing, which an agent would not learn from annotations or schema alone.

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 authored content is two short, front-loaded sentences with no waste. The pricing block is boilerplate disclosure rather than tool prose, but it does consume roughly half the visible text.

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?

An output schema exists, so return values need no explanation, and the schema fully documents all 12 optional filters. The gaps are the absence of any usage routing among the many search siblings and no note on pagination semantics, which matters for a 12-param search endpoint.

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?

All 12 parameters have schema descriptions (100% coverage), including value formats like YYYY-MM-DD and seconds for durations, so the schema does the heavy lifting. The description adds nothing about parameter meaning, which is acceptable at this coverage level but offers no extra value.

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?

"Search calls" gives a specific verb (search) and resource (phone calls), which distinguishes it from write siblings like post_apollo_phone_calls and put_apollo_phone_calls_id. However, it does not differentiate from other search siblings (e.g., get_apollo_emailer_messages_search, post_apollo_tasks_search) or clarify the scope of what is searchable.

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 only guidance is the prerequisite "Requires a master API key." There is no statement of when to use this tool versus alternatives, no exclusions, and no description of the searchable context (e.g., logged calls in the Apollo account).

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