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

Beyond the annotations (readOnlyHint, idempotentHint, etc.), the description discloses the exact curated field set returned, explicitly excludes the 700+ raw upstream columns, states the data source and auth requirement, and notes the dataset is frozen. This adds substantial behavioral context an agent needs to set expectations correctly.

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 dense and every sentence earns its place: the main action, the curated return shape, the exclusion of raw columns, the prerequisite tool, the data source and auth, and the historical coverage. No fluff or 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?

Given that an output schema exists, the description does not need to enumerate return fields. It covers the data source, licensing/auth, temporal coverage, and the prerequisite call to location_search. An agent has everything needed to invoke the tool correctly without surprises.

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%, so each parameter is already well-documented. The description adds minor context (e.g., 'optionally windowed by start_date/end_date') and reinforces the location_key prerequisite, but it does not materially go beyond what the schema already conveys.

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 action ('Get the full daily historical COVID-19 time series for one location') and the resource, distinguishing it from raw upstream data and implicitly from latest-snapshot tools. The mention of 'HISTORICAL DATA ONLY' and 'Does NOT return the raw upstream dataset' helps an agent separate this from global-health-covid.epidemiology.latest_snapshot and other COVID 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 instructs the agent to use global-health-covid.location_search first to find a valid location_key, and notes the data is historical only (coverage ends ~2022-09). It does not explicitly name an alternative for current data (e.g., latest_snapshot), but the historical-only warning strongly implies that distinction.

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