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

Annotations already establish readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds valuable behavioral context by disclosing the nature of evidence per market (e.g., 'construction-PIT diagnostic', 'current-amended vintage', 'no cohort claim'), which informs the agent about data limitations without contradicting 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?

Two sentences carry the full meaning: the first gives the market-by-market status summary, the second provides routing guidance. Every clause earns its place, and the most important information (what this tool is) is front-loaded.

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 parameterless overview tool with no output schema, the description provides sufficient context: it states the scope, summarizes the content for each market, and points to detail tools. An agent can invoke it correctly and interpret its results without additional information.

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 schema coverage is 100% by default. The description doesn't need to explain parameters; instead, it clarifies what the tool will return (a cross-market status summary), which serves the same purpose of setting invocation expectations. Baseline 4 for zero-parameter tools is appropriate.

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 identifies the tool as a historical evidence status overview covering India, US, and Europe, with specific qualifiers for each market. It distinguishes itself from detail-oriented siblings by explicitly naming evidence_india, evidence_us, and evidence_europe as the next step.

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' is an explicit directive to use this tool first for a high-level status, followed by 'then evidence_india, evidence_us or evidence_europe for details,' which names alternatives and the condition for choosing them. This leaves no ambiguity about when to use this tool versus its siblings.

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