Data sources, vintages and known gaps

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

Annotations provide readOnlyHint=true, so the description doesn't need to disclose side effects. It does add value by explaining that the tool reveals 'known gaps' and 'what it cannot know,' which is beyond the annotation. It also implies the tool is safe to call given read-only nature. No contradiction with 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 two sentences with a dash-separated clause, front-loaded with 'What this server knows.' It packs a lot of meaning efficiently—sources, timing, limitations, and when to use—without redundancy. Slightly wordy but appropriate for the scope; not overly verbose, but could be trimmed. Still earns 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?

The tool has an output schema, so return values are documented elsewhere. The description covers what data it exposes, when to call it, and what limitations exist. Nothing important is missing given the complexity and the presence of an output schema. It's fully sufficient for an agent to decide whether and when to invoke it.

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?

The tool has zero parameters, and the schema is empty with 100% coverage (nothing to cover). The description adds no parameter-specific information because there are none to document. Baseline for 0 params is 4, and the description doesn't need to compensate for missing schema documentation.

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 clearly states the tool's purpose: it tells about the server's data sources, vintages, and known gaps. This distinguishes it from sibling tools like portfolio_overview or national_benchmarks, which are about data content rather than metadata/health. The phrase 'What this server knows, from where, as of when — and what it cannot know' is specific and descriptive.

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 explicit usage guidance: 'Call this when asked about data freshness, reliability, methodology, or why an answer is qualified.' This is clear when-to-use instruction. It also mentions the mirrored resource, which adds context for alternative access, though it doesn't explicitly mention sibling tools for exclusion—but the guidance is sufficient.

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