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

Discloses a hidden side effect beyond the annotations: the estimate is automatically refreshed (a write, consistent with readOnlyHint=false) when it is older than 30 days and the property is a Maison or Appartement, and specifies the 10-credit cost. This conditional mutation and cost detail would be impossible to infer from the structured fields alone.

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?

Front-loaded with the core action, then conditions, required param, return value, and cost in terse blocks. The credit cost is stated twice ('10 credits' and the Cost line), a minor redundancy, but overall efficient.

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?

No output schema exists, yet the description specifies the return payload (property record + estimate_refreshed boolean) and covers the refresh conditions and cost, so an agent has everything needed to invoke it correctly without surprises.

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 coverage is 100%, so the sole parameter is already documented, but the description adds real meaning by stating the id's provenance (from list_portfolio_properties or add_property_to_portfolio) and marking it REQUIRED, which is beyond the bare 'Property ID' schema text.

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 ('Get a single portfolio property by ID') and the word 'single' implicitly contrasts with the sibling list_portfolio_properties. It does not explicitly name the alternative as a contrast, so it stops short of a 5.

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 tells the agent where the required id comes from (list_portfolio_properties or add_property_to_portfolio), which is useful sourcing context, but gives no explicit when-to-use vs when-not guidance relative to siblings like list_portfolio_properties or update_portfolio_property.

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