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

Annotations already cover readOnly/idempotent/non-destructive, so the description's added value is the cost and scope profile: free, no payment, and deliberately limited to metadata with zero paid or record data returned. That is useful context an agent would otherwise have to infer, though response shape/pagination is not discussed (no output schema exists to cover it).

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 scope statement is front-loaded, but the free/no-payment point is repeated three times ('FREE', 'Free — no payment required', 'no paid data'), and the em-dash clauses make the second sentence dense. It is compact but contains clear 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?

With no parameters and no output schema, the definition still names the exact returned fields and points to the external endpoint for the full document, which is what an agent needs before calling. Only the response encoding/format of the descriptor is left unspecified.

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 and the schema is fully closed (additionalProperties: false), so there is nothing for the description to disambiguate. Baseline for a 0-param tool applies.

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?

States a specific verb and resource: returns only the snapshot descriptor with its three fields (generated_at, service count, byte size). It explicitly carves out what it does NOT return (no service records, no paid data), which separates it from the adc_* family, though no sibling tool is named directly.

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?

Tells the agent when this applies (free descriptor, no payment) and when it does not (it is not the snapshot itself — that is the REST GET URL), plus 'call it directly' removes any preflight ambiguity. It stops short of naming which adc_* tool to use when actual records are needed.

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