Data coverage / what's missing

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

Annotations already indicate readOnlyHint=true and idempotentHint=true, so the tool is safe. The description adds value by detailing the two operational modes and what each mode returns (presence, dates, staleness, empty domains), providing behavioral context beyond annotations.

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 well-structured with a clear purpose statement and bullet-like enumeration of modes and outputs. It is appropriately detailed without redundancy, though slightly lengthy. Each sentence adds value, earning a 4.

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?

Given the complexity of two modes and comprehensive output (inventory, per-domain counts, empty domains, etc.), the description covers all necessary behavior. An output schema exists, so return values don't need elaboration. The description is fully sufficient for correct agent invocation.

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%, with each parameter having a clear description. The description adds interaction semantics: explaining how the combination of 'name' and 'source' triggers one mode vs the other, which helps the agent understand parameter relationships beyond individual schema descriptions.

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 title 'Data coverage / what's missing' and description clearly state the tool exposes what data exists and what's absent/stale. It distinguishes two modes (specific signal vs whole-record inventory), making the purpose unambiguous and distinct from sibling list tools.

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 explicitly states the purpose: 'let the model check the record before asserting, instead of confabulating around missing values.' This clarifies when to use the tool. It doesn't explicitly mention when not to use or alternatives, but the context is clear enough for decision-making.

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