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

With no annotations, the description carries the full burden, and it does disclose the key non-obvious trait: the call blocks up to wait_seconds and may return while still in progress, requiring re-polling. It omits error behavior (invalid/expired call_id), whether the transcript is partial mid-call, and any auth or rate-limit constraints beyond the api_key parameter.

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 sentences, zero waste. Return payload is front-loaded, then the blocking/polling behavior follows immediately after.

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?

No output schema exists, so naming the returned fields (status, outcome, summary, transcript) is genuinely necessary and it is done. The polling contract is covered. What is missing is failure-mode guidance for an invalid call_id or a call that never completes.

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 67%: api_key and wait_seconds are already documented in the schema (default 90, max 120), so the description only restates the wait semantics. The lone undocumented parameter, call_id, gets no description beyond the implied origin from make_phone_call and its format is unstated.

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 and resource ('Get the result of a call') and enumerates the return contents (status, outcome, summary, transcript). It also names the sibling that produces the call_id (make_phone_call), so an agent can place it precisely against list_phone_numbers, make_phone_call, and the other siblings.

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?

Explicitly frames this as the follow-up to make_phone_call and gives a retry rule: 'if it's still going, call again.' That is real when-to-use guidance. It stops short of stating exclusions or what to do on a terminal failure (e.g. bad call_id), so not a 5.

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