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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral context beyond that: it clarifies JooVoice sends nothing and starts nothing, and that the recipient must confirm their number and press Start, which is important for setting agent expectations about side effects.

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?

Three sentences that are front-loaded with the core action, followed by usage and behavioral caveats; there is little waste. The middle sentence is slightly awkward but still earns its place by clarifying who sends the link.

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 present, the description need not explain return values, and the annotations cover the read-only safety profile. It discloses the downstream flow (recipient confirms and presses Start) that an agent needs to act correctly, leaving only minor gaps around alternative recipient tools.

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%, so the taskId parameter is already well documented in the schema, including sourcing hints from prepare_task, list_tasks and find_task. The description adds nothing about the parameter, so the 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?

The description gives a specific verb (Get) and resource (a personal call's Start link, plus a ready message), so an agent knows this returns shareable artifacts rather than mutating state. It does not explicitly name how it differs from recipient-related siblings like set_recipient, but the returned 'link + message' framing is distinct enough to be actionable.

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 owner sends it, or you do if they ask and you can' gives implied usage context about who acts on the link, which is useful. However, there is no explicit when-to-use-vs-alternative guidance, and the 'if you can' clause is vague rather than routing the agent to a specific sibling.

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