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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description's one contribution is telling the agent the payload includes the statement's rows and its reconciliation, which is genuinely useful since there is no output schema — but it says nothing about what reconciliation status looks like or behavior for an unknown/source-not-found ID.

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?

A single tight clause with zero padding, and the key payload detail (rows + reconciliation) is front-loaded. It is arguably over-compressed — a fragment rather than a sentence — but nothing is wasted.

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 one-parameter read tool whose annotations cover safety, the description is minimally sufficient, and 'with its rows and reconciliation' partially compensates for the absent output schema. It still leaves the agent guessing how this differs from purch_sources and purch_transactions, which is the main risk in a 150+ sibling namespace.

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% and the source_id property even carries an example ('e.g. SRC-0001'), so the schema does the heavy lifting. The description adds no meaning about the identifier's origin (e.g. that IDs come from purch_sources) or format expectations beyond 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 description identifies the resource (a single statement, i.e. one source) and notes it comes with its rows and reconciliation, which hints at the plural sibling purch_sources being the list form. But it is a noun phrase with no verb — an agent must infer 'retrieve/fetch' — and it never names the source_id argument or explicitly contrasts with purch_sources, purch_get_transaction, or purch_import_statement.

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?

No when-to-use guidance at all: nothing says to call this after purch_sources lists IDs, or to use it instead of purch_transactions when you need the whole imported statement. The singular/plural relationship with purch_sources is only implied by the name.

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