Summary

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

Annotations already cover the safety profile (readOnly, idempotent, closed-world), and the description goes beyond them by disclosing timezone handling (all times UTC), accepted date formats, and the inclusive-boundary rule for from_date and date-only to_date. Boundary semantics are exactly the kind of behavior that causes off-by-one errors, so this is real added value; return format is left to the output schema.

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 sentences, front-loaded with what the tool returns, then only the temporal semantics an agent could get wrong. No filler and no restatement of the tool name.

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?

Output schema exists so return values needn't be spelled out, all five optional filters are documented, and the date edge cases are resolved. The only missing piece is routing guidance versus the sibling transaction and source tools.

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 baseline would be 3, but the description adds meaning the schema lacks: UTC as the reference zone, that a date-only value means 00:00Z, and explicit inclusiveness for from_date. It adds nothing for asset, source, or direction, which the schema already handles.

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 resource and output shape: per-asset totals of credit, debit, net and count over filtered transactions. That aggregation framing implicitly separates it from the transaction-listing siblings, but no sibling is named explicitly, so it stops short of a 5.

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?

Use is only implied by 'over the filtered transactions' — an agent can infer this is the aggregation counterpart to the list/get tools. There is no explicit when-to-use statement, no exclusion, and no pointer to list_sources or get_transaction as alternatives.

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