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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's added value is the data-scope disclosure: India is a 48-institution construction-PIT diagnostic, US is an industry-wide current-amended vintage, and Europe is 'named cases, no cohort claim' — that last phrase is a real caveat about statistical representativeness that structured fields do not convey.

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, no filler, and the market-by-market breakdown is front-loaded before the routing instruction. Slightly dense parenthetical packing keeps it off a 5, but every clause carries information.

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 zero-parameter, read-only hub tool with no output schema and full annotation coverage, the description supplies what an agent needs: what each market's evidence represents, its quality caveats, and where to drill down. Only the shape of the returned summary (counts vs. prose status) is left implicit, which is a minor gap given the tool's simplicity.

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 takes zero parameters, so there is nothing about argument semantics to explain and the baseline of 4 applies. The description correctly focuses its limited space on scope and routing instead of inventing parameter guidance.

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 makes clear this is an all-markets overview of historical evidence, enumerating the three markets covered (India, US, Europe) with a qualifier for each. It does not use an explicit verb like 'list' or 'summarize', but the noun-phrase form plus the title leaves no ambiguity about the resource, and the sibling drill-down tools are named so the agent can distinguish this hub from evidence_india/evidence_us/evidence_europe.

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?

'Start here, then evidence_india, evidence_us or evidence_europe for details' gives explicit sequencing and names the alternatives an agent should fall back to. It stops short of stating when to skip this tool (e.g., if the market is already known), but the routing intent is unambiguous.

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