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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description earns credit for adding context beyond them: it explicitly says it 'computes nothing new, it reports the canonical ledger' and that it 'Requires a connected Aurgus account' — a real auth prerequisite an agent needs. It stops short of disclosing whether the list is bounded or paginated.

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?

The lead sentence front-loads the resource and the returned fields, and the mode/argument instructions follow logically. Slightly padded by the 'book-at-a-glance a controller watches' framing, but no sentence is redundant with the schema.

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?

With no output schema, the description usefully enumerates the returned fields (accrual breakdown, basis, status, last calculated), which is exactly what an agent needs to judge relevance. Remaining gaps are minor: no list-size/pagination behavior for 'every active agreement' and no precedence rule when both parameters are passed.

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%, so both optional parameters are already documented, making 3 the baseline. The description restates the agreement_id/status modes and enumerates four status values, but omits the 'all' enum value and never says what happens if both parameters are supplied together.

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+resource: returns every active agreement with earned/settled/open accrual, basis, status and last-calculated timestamp, plus the single-agreement mode. That is far more specific than the name 'report' alone. However, it never distinguishes itself from siblings like run_report, list_reports, or export, which an agent will see in the same namespace.

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?

It gives the invocation modes (pass agreement_id for one, status to filter the list) and frames the use case as 'the book-at-a-glance a controller watches.' That implies when to call it, but there is no explicit when-not, and no routing against run_report, list_reports, or export, which are the obvious confusable siblings.

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