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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds a non-obvious dependency on an existing session and reinforces the YYYYMM date constraint. However, it does not disclose what the returned statistics contain or how pagination behaves, which matters for a tool with no 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?

The description is two short sentences with no filler. The critical prerequisite is front-loaded, followed by the core action and the most important parameter-format example. Every sentence earns its place.

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?

The description adequately covers invocation requirements: session dependency, date-range format, and the tool's core purpose. However, without an output schema, the substance of the returned 'monthly statistics' is left undefined, and the relationship to sibling search_summary/search_list tools is not clarified. It is sufficient for a straightforward call but not fully self-contained.

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 the baseline is 3. The description adds value by giving a concrete date-range example and tying account_link_id to the preceding login call, which is not obvious from the schema alone. The remaining parameters are already well-documented in 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 states a concrete action and resource: 'Search e-tax invoice monthly statistics.' This clearly distinguishes it from invoice issue/modify tools. However, it does not explicitly contrast it with sibling search_list or search_summary tools, so it stops short of full differentiation.

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?

The description provides a clear prerequisite: a prior hometax__session__login call with the same account_link_id. It also gives explicit date-format guidance for the required parameters. It does not name alternative tools or say when not to use this one, but the usage context is clear.

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