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 genuinely useful context beyond that: it is explicitly non-sending and points to rewrite_outreach/send_outreach for the mutating paths. Return-format detail is left to the output schema, which is appropriate.

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 tight sentences, front-loaded with the core purpose before the scoping rule and the disambiguation. No filler, though the sibling callout sentence is slightly compressed in a way that reads as two thoughts stapled together.

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?

Output schema and annotations are rich, and the description covers the remaining gaps: what the queue means, default scoping, and that the tool is read-only relative to its write siblings. An agent has everything needed to call it correctly.

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 both parameters are already documented, including campaignId's omit-to-list-all behavior. The description restates that behavior but adds no syntax, format, or default detail (e.g. limit) beyond the schema. Baseline 3 when the schema does the heavy lifting.

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+resource ('lists outreach messages the agent has drafted') and pins down the exact concept via the 'a message for X is ready' queue. An agent can distinguish this from list_replies or list_next_steps without opening any schema.

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?

Explains scoping explicitly ('Without campaignId, the list covers every campaign in this workspace') and names the two sibling tools that perform writes, clarifying this one does not. It stops short of stating when an agent should prefer this over e.g. list_replies, so it is clear context rather than full when/when-not guidance.

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