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

Annotations already declare the write profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false), so the safety bar is lower. The description adds real context beyond that: automatic estimate computation for Maison/Appartement, metadata-only storage for other types, and a credit cost of 10 vs 2. It does not mention auth requirements or whether repeated calls create duplicates.

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 and the key conditional cost, and reasonably compact. Slightly redundant: the credit cost is stated twice (inline parenthetical and a trailing 'Cost:' line), which costs a sentence without new information.

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 steps in to say it returns the created property record with estimate fields, which is what an agent needs. Credit pricing and the estimate-vs-metadata branching are covered. It stops short of covering duplicate handling, idempotency behavior, or any error conditions.

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 description coverage is 100%, so every parameter is already documented in the schema, including the type_local enum. The description's required/optional listing merely restates what the schema's required array and field descriptions already encode, adding no format or constraint detail beyond it. Baseline 3 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 (Add) and resource (property to portfolio), clearly distinguishing it from the sibling update_portfolio_property, delete_portfolio_property, and list_portfolio_properties tools. An agent can identify the create operation without opening the schema.

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?

Implies usage (adding a property to your portfolio) but never states when to prefer this over siblings like estimate_property_value or update_portfolio_property. It does disclose a type-conditional behavior (estimate computed for Maison/Appartement, metadata only otherwise), which is useful, but no explicit when-not guidance or named alternatives.

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