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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the agent knows it's a safe read. The description adds valuable behavioral context beyond annotations: the dependency on prior processing status and the specific 409 error behavior. This exceeds baseline transparency.

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 concise sentences: the first states purpose, the second gives a critical usage condition and expected error. No filler or redundancy; information is front-loaded and directly useful.

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 tool's moderate complexity, strong annotations, and presence of an output schema, the description sufficiently covers the key operational constraint (completion prerequisite) and error handling. It is complete for an agent to decide when and how to invoke this tool reliably.

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 100%, with both parameters (list_id and format) having meaningful descriptions. The description does not add parameter-specific details beyond the schema, but it does subtly reinforce that the export is for completed lists. Thus, it meets the baseline for high schema coverage without adding extra semantic 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?

The description uses a specific verb ('Download') and a clear resource ('generated email sequences for a COMPLETED list'). It distinguishes itself from sibling tools like generate_batch, generate_sequence, and get_list_status by focusing on exporting results rather than creating or monitoring.

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?

Provides explicit when-to-use guidance: only after get_list_status shows processing_status = 'completed'. It also explains the failure mode (409 error) and instructs to poll first, which is highly actionable for an agent.

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