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

The annotations already declare readOnly, idempotent, non-destructive, closed-world behaviour, so the safety profile needs no repetition. The description contributes the useful nuance that counts reflect statuses 'now', i.e. a live snapshot rather than a frozen result. It does not cover retention or whether the batch record persists after cancellation.

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 sentence with the action front-loaded and the payload description following. The nested parenthetical is slightly dense but short and every clause carries information. Nothing is padded or redundant with structured fields.

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?

A single-parameter read tool with a full output schema and rich annotations needs little prose, and this is enough to call it correctly. The only shortfall is the absence of any edge-case guidance for invalid ids or post-cancellation lookups, which the annotations and output schema cannot supply.

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% and already types the single parameter, so the baseline is 3. The description earns above baseline by explaining provenance: the id is the one a batch send returned and also appears as batch_id on each constituent email. That directly helps an agent obtain a valid 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?

States a specific verb and resource (get a batch send) and defines the returned payload as email totals broken down by current status. That is more specific than the title 'Get batch'. It does not explicitly contrast with list_emails, which is the nearest sibling for per-email inspection.

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?

Usage is implied rather than stated: 'Get a batch send' plus the note that batch_id comes from a send response tells the agent the object exists and where its key comes from. There is no explicit when-to-use guidance, no mention of cancel_batch as the related action, and no note on behaviour for an unknown or expired batch_id.

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