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

Annotations already declare read-only, idempotent, non-destructive behavior, yet the description adds genuinely new context: the result is a download link with a one-hour validity window and one row per leg. It stops short of stating any rate limits or what happens when the link expires, so it is strong but not exhaustive.

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 sentences, zero filler, with the output format and link lifetime front-loaded before the sibling comparison. Every clause carries information an agent needs to choose or call the tool.

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?

There is no output schema, and the description compensates by describing the return artifact (CSV via download link, one hour validity). Combined with full schema coverage of the five parameters, nothing material is missing for a read-only export tool.

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%, with from/to/source/account/currency all documented in-schema including the multi-currency rule, so the schema does the heavy lifting. The description adds only the row granularity ('one row per leg') and says nothing about the required date range or filtering parameters, so the baseline 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 and resource ('Return the period's ledger lines') plus the output format ('RFC 4180 CSV, one row per leg, as a download link'). It explicitly distinguishes itself from the sibling ledger_lines, so an agent can separate the two without opening either schema.

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?

Names the alternative (ledger_lines) and the exact condition that selects it: the same fields are free and unlimited there, and this tool only re-lays them out as CSV columns. That is an explicit when-to-use/when-not-to-use rule rather than an inference.

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