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

Beyond the readOnlyHint annotation, the description discloses an important nuance: catalog presence does not prove loaded, fresh, or complete coverage, and platform coverage is separately dated. This adds meaningful behavioral context that the annotation alone does 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?

The description is two sentences, front-loaded with the main purpose, and every clause adds value. It avoids redundancy and clearly communicates both functionality and limitations without unnecessary verbosity.

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 simple list tool with no parameters and no output schema, the description covers the tool's purpose, the content of the catalog, and important caveats about data freshness. It also gives concrete use cases, making it complete enough for an agent to select and invoke the tool correctly.

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 no parameters, and the schema coverage is 100%, so there are no parameter semantics to clarify. The baseline for zero-parameter tools is 4; the description also mentions the output fields, which helps set expectations even though it is not about parameters.

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 listing Fonteum's public-record source catalog, specifying what fields are included (authority, vertical, cadence, official URL, platform coverage). This distinguishes it from sibling lookup/search tools, which target specific records or datasets.

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 states when to use this tool: 'for source discovery, coverage questions, or choosing a dataset before a lookup.' It also provides a key caveat that catalog presence does not guarantee loaded or fresh coverage, helping the agent decide if this tool is appropriate versus other tools.

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