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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds the shape of the returned data (sent, replies, spam_to_inbox, ESP split), but that partly duplicates the output schema and omits freshness, retention window, or behavior for senders with no warmup data.

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?

One compact sentence with no wasted clauses. It is slightly front-loaded with a restatement of the title, and the parenthetical field enumeration is the bulkiest part of the sentence.

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?

Because an output schema exists, the description did not need to enumerate return fields, yet that is where nearly all of its text goes. The genuinely missing context is sibling differentiation and edge-case behavior, so it is adequate but incomplete.

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 id, days (max 90) and workspace_id semantics are already fully documented in the schema. The description adds no parameter-level detail such as defaults or what happens when days is omitted, 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 identifies a specific resource (sender warmup stats) with a verb (Get) and clarifies scope as date-wise plus a per-ESP breakdown, which goes slightly beyond the title. It does not differentiate from closely related siblings such as get_sender_health, get_warmup_links, or the get_analytics_* family.

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?

There is no statement of when to use this tool versus alternatives, no prerequisites, and no exclusions. An agent must infer from the name alone that this is the per-sender warmup view rather than the health or analytics views.

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