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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false and idempotentHint=false, so the safety profile is covered. The description adds genuinely new behavioral facts: a hard cap of 50 entries, newest-first ordering, no paging, and amounts denominated in cents. It stops short of stating behavior on an empty ledger, which is the only remaining gap for a read tool.

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 tight sentences: scope and shape first, then routing to alternatives. Every clause carries information (ordering, cap, no paging, units) and nothing is repeated from the schema or annotations.

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 an output schema present, return values need not be described, and the description covers the remaining agent-facing concerns: cap, ordering, no paging, units, and which sibling to use for adjacent questions. Nothing material 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?

The tool takes zero parameters, so the baseline is 4. The description correctly and explicitly says 'takes no arguments', which preempts an agent from guessing at filter or paging parameters.

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 (List) and resource (this agent's wallet ledger entries) plus scope (50 most recent, newest first), and explicitly contrasts itself with getBalance and listDecisions. An agent can select this over either sibling without opening a 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 two alternatives with the exact condition that selects each: getBalance for the current total, listDecisions for what was bought or passed over and why. No inference required.

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