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

Annotations declare destructiveHint=true, idempotentHint=true, readOnlyHint=false, so safety is partly covered. The description still adds real value beyond them: pausing is scoped to all inboxes the site sends from, it does not halt outreach, and there is a deliverability cost to long pauses. It does not clarify reversibility timing or whether pausing affects in-flight warmup mail, so it's strong but not exhaustive.

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, no padding, and the core action plus scope lead. The sibling disambiguation and the consequence warning each carry distinct information, so every sentence earns its place.

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?

For a two-parameter, no-output-schema mutation tool with annotations already covering the safety profile, the description supplies everything else an agent needs: scope of effect, the sibling boundary, the side effect on outreach, and the risk of misuse.

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% and the schema already documents both parameters, including the boolean polarity ('true to resume warmup, false to pause it'). The description adds no parameter-level detail beyond that, 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?

States a specific verb pair (pauses/resumes) and resource (inbox warmup) with scope nailed down: 'on every inbox this site sends from'. It explicitly names the sibling it is not (set_sending) and explains the functional difference, so the agent can distinguish it 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?

Gives explicit routing guidance against the closest alternative: 'Separate from set_sending: warmup mail is exchanged with a warmup network, not sent to prospects.' It also states a when-not-to-casually-use condition ('a long pause on a young inbox can cost deliverability'), which is actionable context most definitions omit.

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