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

Strong disclosure beyond the annotations: it states the partial-success contract ("a single bad row does NOT roll back the batch"), the exact return envelope shape, replay tagging via status='replayed', and the confirmation gate. The only tension is idempotentHint=false in annotations versus the emphasis on per-row idempotency, but that is genuinely compatible — the call itself is not idempotent, only keyed rows are — so it is a nuance, not a contradiction, though the description could have made that distinction explicit.

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 tight sentences, front-loaded with the operation and then the return/behavior contract. The inline envelope notation conveys the response shape faster than prose would, and nothing is repeated or padded.

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?

There is no output schema, so the description carries the burden of explaining return values — and it does, with the partial-success envelope and per-row results. Combined with the maxItems=25 and required confirmation in the schema, an agent has everything needed to call this 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?

With 67% schema coverage, the schema already documents accountId, confirmation, and idempotencyKey. The description adds real meaning on top: duplicates short-circuit and return the original response tagged as replayed, and it reinforces the confirmation requirement as a call-level gate rather than just a boolean field. It does not elaborate on row-level fields like amount or date, but those are self-explanatory in the schema.

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 opening sentence gives a specific verb and resource ("Add multiple transactions in one call") and immediately names the property that separates it from the single-row add_transaction sibling: batch scope plus per-row idempotency. An agent can tell what this does and why it exists alongside add_transaction without opening either 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?

Usage is implied rather than stated: "in one call" signals batch use and "Requires confirmation: true" is a hard prerequisite, but the description never says when to prefer this over add_transaction (e.g., how many rows justify a batch) or when not to use it. The prerequisite is useful, but there is no explicit alternative routing.

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