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

Annotations already declare readOnly, idempotent, and non-destructive, so the safety profile is covered. The description adds real value beyond them: the explicit 'Requires sign-in to Untap' auth requirement and an explanation of what each returned row carries (verdict status plus user_progress).

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?

Three tight sentences with the core action and filters front-loaded before the auth note. No filler, though the 'and so on' phrasing adds a slight vagueness rather than cutting it.

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 no output schema, the description usefully describes the shape of returned rows and the auth requirement. It omits pagination/ordering behavior and does not reconcile the user_progress values with the status enum, but is otherwise adequate for a read-only list 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 description coverage is 100%, so the baseline is 3. The description clarifies what the status values mean semantically, but it also introduces a 'user_progress' value set (none/submitted/received/archived) that does not match the schema's status enum, which risks confusing rather than clarifying the parameter.

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 ('Lists the savings rows in the person's Untap account, filtered by category and status'), which is clearly distinct from siblings like list_my_claims or list_commutes. However, it never explicitly contrasts itself with those sibling tools, so the differentiation is implicit.

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 notes the sign-in prerequisite and explains what the filter values represent, which implies when the tool is useful. But it never says when to prefer this over find_money_owed or list_my_claims, nor any exclusion conditions, leaving usage to inference.

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