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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered; the description adds the non-obvious semantic trait that expected_income rows are unpaid sales invoices rather than money received, which is exactly the kind of interpretive context annotations cannot carry. It also names the three returned fields an agent needs to reason about currency conversion.

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?

Three tight sentences: purpose first, then the returned fields, then the accounting trap, then the sibling alternative. No restatement of the name or title and no filler.

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 13-parameter read tool with no output schema, the description covers the highest-risk misinterpretation (expected_income) and the shape of the returned rows. It does not mention result ordering or that paging defaults live in the schema, but nothing critical to correct invocation is missing.

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 every one of the 13 parameters is already documented in the schema. The description says only 'optional filters' and adds no syntax, ordering, or interaction semantics (e.g. how min/max_amount combine with direction). Baseline 3 applies when the schema does all the work.

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 transactions for the company') plus the fields returned (currency, amount_gbp, exchange_rate), so the agent knows what it is retrieving. It names one sibling it is not (get_income_by_currency) but does not differentiate from the many other ledger-reading siblings (get_expenses, get_bills, get_journal_entries).

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?

Gives an explicit alternative for currency-split income totals ('prefer get_income_by_currency') and an explicit exclusion rule: rows with expected_income: true must not be counted as cash or income received. It stops short of saying when this tool is the right call versus e.g. get_expenses or get_bills, but the routing guidance it does give is concrete.

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