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

readOnlyHint=true already establishes this is a safe read. The description adds useful context about what the log contains and cites the HTTP endpoint, but says nothing about pagination behavior despite a startingAfter cursor, nor about ordering or result volume.

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 with zero filler, front-loading the resource and its contents before the endpoint reference. Nothing is redundant.

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 read-only list tool with full schema coverage and annotations covering safety, the description is nearly complete; no output schema is declared, so return-value detail is not required. Only the pagination/cursor behavior is left implicit.

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 all five parameters (invoiceId, limit, startDate, endDate, startingAfter) are already documented in the schema. The description adds no format or semantic detail beyond that, so the baseline of 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 ('Get') and resource ('event/audit log for an invoice'), and enumerates the content types (status changes, approvals, payments), so the agent knows exactly what comes back. The 'for an invoice' scoping cleanly separates it from the sibling mercoa_get_entity_events.

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 by describing the log contents, but there is no explicit when-to-use guidance and no named alternative (e.g., mercoa_get_invoice for the invoice itself). The agent can infer intent but must guess at routing versus siblings.

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