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

Annotations already cover safety (readOnly, openWorld, idempotent, non-destructive). The description adds valuable behavioral context beyond annotations: it's 'FREE ($0, unlimited, no payment, no wallet)' and returns representative examples of every response shape. This is more than the annotations provide, though it doesn't detail response structure or size limits, which is acceptable given the sample nature.

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 a single dense paragraph that front-loads the free aspect and the purpose, then gives usage instruction and alternative. Every sentence carries information, though it could be slightly tightened. The structure is logical and not overly verbose for the information conveyed.

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 the tool has no parameters and no output schema, the description compensates fully by explaining exactly what is returned (the list of response shapes), the use case (validation), and the alternative for real data. Nothing an agent needs to call it correctly is missing.

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?

There are zero parameters, so the schema fully covers them (100%). Baseline for zero params is 4. The description doesn't need to add parameter semantics, and it doesn't attempt to. The lack of params is itself a clear signal.

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 returns 'a fixed, representative example of every response shape this server returns for Cook County / Chicago property data' and enumerates the data types (address search, parcel, dossier, comparable sales). It distinguishes itself from siblings by explicitly noting it's a sample for validation, not real data.

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?

Explicitly instructs to 'Call this FIRST to validate the data structure before anything else.' It also provides an alternative for real data: 'For REAL verified data at $0, call get_cook_county_property_dossier with one of the always-free example PINs...' This gives both when-to-use and when-not-to-use guidance.

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