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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds the one non-obvious behavior — newest-first ordering — but says nothing about pagination defaults or the dual response shape, which the schema alone carries.

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?

A single front-loaded sentence with zero padding; the ordering fact is stated immediately. The raw snake_case resource name is slightly awkward but not wasteful.

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?

For a simple two-parameter list tool this is close to sufficient, but with no output schema the description could have noted the two possible return shapes (bare array vs cursor envelope), which materially affect how an agent consumes the result. That gap is only covered indirectly in the parameter schema.

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%, including the unusual legacy bare-array vs { items, next_cursor, limit } behavior and cursor semantics, so the schema does the heavy lifting. The description adds no parameter guidance beyond that, making the baseline 3 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?

States a specific verb and resource ("List your expense_category rows") and adds an ordering guarantee ("newest first"). It is clearly separable from expense_category_read/create/update/delete, though it doesn't explicitly name distinguishing conditions versus those siblings.

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?

There is no statement of when to use this versus expense_category_read (single row) or expense_search, and no prerequisites or exclusions. Usage is only inferable from the verb "List".

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