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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds useful behavioral context by explaining that the output is meant to be handed to an autonomous worker and that a human-facing card is returned when no worker can be started. It does not describe the exact return shape or any secret-handling behavior, so it adds moderate value beyond annotations.

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 description is short, at three sentences, but it is not front-loaded with a direct statement of what the tool returns. Metaphorical language like 'words' and 'card' makes the structure less immediately useful than a more literal opening would be, though it is not bloated.

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?

Given the low complexity, one optional parameter, full schema coverage, and annotations, the description covers the intended consumer of the output and the fallback behavior. It still leaves ambiguity about the exact return type and does not clarify how this tool relates to siblings such as answer_call or get_line, so it is only minimally complete.

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?

There is one optional parameter and schema description coverage is 100%, so the schema already documents the secret parameter thoroughly, including where it comes from and how to handle it. The description does not mention the secret parameter at all, so with high schema coverage the baseline score of 3 is appropriate.

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 conveys that the tool provides 'the words for a helper that answers your line,' which suggests a briefing or prompt for a call-answering worker. However, it never states an explicit verb such as 'get' or 'return,' and the metaphorical phrasing ('words,' 'line,' 'card') leaves the exact resource ambiguous. It also does not clearly differentiate this tool from siblings like answer_call or call.

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 gives a clear when-to-use rule: if you can start an autonomous worker, sub-agent, task, or routine, start one and give it these words. It also states a fallback for when no autonomous worker is available: the tool gives a card to show your human. The guidance lacks explicit comparison to other call-related MCP tools, but the usage condition itself is reasonably clear.

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