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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, and the description adds real context beyond them: the result ordering (newest first), the fact that estimates are cached and may be stale, how to force a refresh, and that the call costs 0 credits.

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?

Four short lines, front-loaded with what is returned, then ordering, then the caching caveat and refresh path, then cost. Every sentence carries information an agent would otherwise have to guess.

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 output schema, the description carries the burden of describing the return value, and it does so ('array of property records ordered by creation date, newest first') along with the staleness caveat. For a zero-parameter read tool this is complete enough to call correctly on the first attempt.

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 no parameters, so there is nothing for the description to disambiguate; baseline for a zero-param schema applies. The description correctly spends no words on parameters and instead covers scope and return behavior.

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 ('List all properties in your portfolio') plus what is attached to each record ('their cached estimates'). It also distinguishes itself from the sibling get_portfolio_property by contrasting cached listing with a refresh-triggering single-property fetch.

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?

Gives a clear use case (browse the whole portfolio) and explicitly routes the agent to get_portfolio_property when a single property needs a fresh estimate. It stops short of stating exclusions such as when not to list at all, but the alternative-selection guidance is concrete.

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