US Government Open Data MCP

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

Annotations already declare readOnlyHint=true, so the agent knows this is a safe read operation. The description adds useful context about the data being 'provisional' and the specific return fields (rate_overall, rate_sex_female, etc.), which goes beyond what annotations provide. However, it doesn't mention rate limits, data freshness, or authentication requirements.

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 efficiently structured in three sentences: purpose statement, cause examples, and return values. Every sentence earns its place by providing essential information without redundancy. It's appropriately sized and front-loaded with the core functionality.

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 read-only tool with good annotations and 100% schema coverage, the description provides adequate context. It explains what data is returned and the scope of the tool. The main gap is the lack of output schema, but the description partially compensates by listing return fields. It could be more complete by mentioning data limitations or update frequency.

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 the schema already fully documents all 4 parameters. The description adds marginal value by listing example causes and mentioning the default rate type, but doesn't provide additional syntax or format details beyond what's in the schema. Baseline 3 is appropriate when schema does the heavy lifting.

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 with specific verbs ('Get provisional age-adjusted death rates') and resources ('by cause, sex, and state'). It distinguishes from siblings like 'cdc_death_rates_historical' by specifying the time range ('quarterly, 2020–present') and data type ('provisional').

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 implies usage context through the time range and data scope, but does not explicitly state when to use this tool versus alternatives like 'cdc_death_rates_historical' or 'cdc_causes_of_death'. It provides some guidance through the parameter descriptions but lacks explicit when/when-not instructions.

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