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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description's added value is the deduplication intent and the 'own payments only' scoping. It says nothing about result ordering, whether filtered results are exhaustive, or how paging behaves, which leaves real behavioral questions unanswered.

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?

The purpose and rationale are front-loaded, which is good, but the full text is duplicated in Japanese and English, roughly doubling length without adding information. Every clause is relevant, yet the redundancy costs efficiency.

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 three fully documented parameters and no output schema, an agent still does not learn what a returned record contains (merchant, date, status, amount) or whether results are sorted. For a lookup tool whose whole purpose is comparison against prior approvals, that return-shape gap matters.

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 each of the three parameters documents its meaning, bounds, and defaults, so the schema does the heavy lifting. The description adds no filtering or format semantics beyond that, making the 3 baseline correct.

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 states a specific verb and resource ('Look up this agent's own past payment requests') and narrows the scope to the calling agent's own records, which meaningfully separates it from request_payment. It does not explicitly name check_payment_status or get_budget, so the boundary with those siblings must be inferred rather than read.

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?

It supplies a concrete use case with an example ('check whether a Spotify charge was already approved this month, and avoid paying twice'), which tells the agent exactly when this tool is appropriate. It stops short of exclusions — it never says to use check_payment_status for a single known payment or get_budget for spending limits.

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