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

Annotations only declare a safe read (readOnlyHint=true, destructiveHint=false); the description adds the traits that actually matter here — that this long-polls and blocks for up to wait_s (max 30s) and returns {events, cursor}. It also pre-empts the confusing case where an empty list is not an error. Error/timeout behavior is not covered, so it is not fully exhaustive.

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?

Four short sentences, front-loaded with the purpose, then the blocking behavior, then the cursor contract, then the empty-result caveat. No filler and nothing repeated from the schema or annotations.

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?

There is no output schema, so the description correctly carries the return shape ({events, cursor}) and the empty-list semantics. Combined with the safety annotations, an agent has what it needs to call this correctly. It would be complete with a note on what session_token identifies or what a timeout looks like.

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 0%, so the description must carry the parameters, and it does for two of three: it explains cursor as a resume token from the prior response and wait_s as the long-poll bound with a 30s cap. session_token is left unexplained, which for a session-scoped tool is a minor 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 gives a specific verb and resource: waiting for an inbound human message (texts and voicemail transcripts) on this session. It is clear about what arrives and what the call does. It stops short of explicitly contrasting itself with the sibling poll_result, which is the closest analog and would be the obvious confusion point.

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?

It implies when to call (while waiting for a reply) and instructs to poll again on an empty result, but never says when to prefer this over siblings like poll_result or call. No prerequisites or exclusions are stated, so the routing decision is left to inference.

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