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 genuine value beyond that by disclosing a hard dependency on a prior npki login session bound to the same account_link_id — a behavioral requirement an agent must know before calling. That context compensates for the absence of return-format or pagination details.

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 sentences with zero filler, and the most critical piece of information — the mandatory login prerequisite — is front-loaded in caps. Every word earns its place with no redundancy.

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 6-parameter tool with nested objects and no output schema, the description is minimal but the rich schema carries the load. It properly flags the auth dependency. Still, it leaves the relationship to premium_billing_notice__search implicit and says nothing about return shape or error-prone cases like mixed insurance types, so it is merely adequate rather than complete.

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 the schema itself is richly documented (detail_keys passed from detail_candidates, detail_context passed as-is, insurance_type needed only when types mix, account_link_id auto-resolution rules). The description contributes zero parameter information, so it scores at the documented-schema baseline of 3 — the schema earns the credit, not the description.

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: 'Fetch COMWEL premium billing notice detail.' This is clear and unambiguous about the tool's core function. However, it does not differentiate from sibling tools like comwel__info__individual_billed_premium__detail or explicitly position itself as the detail counterpart to premium_billing_notice__search, so it stops short of a 5.

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 leads with a concrete precondition: 'REQUIRES prior comwel__auth__npki_session__login call with same account_link_id.' This is a real, actionable usage context. Yet it gives no guidance on when to choose this over the near-named sibling individual_billed_premium__detail, and the intended search-then-detail flow is only implied via the schema's detail_candidates references, not stated in the description.

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