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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered. The description adds real value by disclosing the return shape: every lot/parcel under the transaction with shared price, date and nature. It does not mention rate limits, auth, or failure behavior for a bad id, which keeps it short of a 5.

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?

Two sentences, front-loaded with the resource and lookup key, then the return content, then the usage rule. No wasted text.

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?

For a single-lookup tool with full annotation coverage and a documented parameter, the description supplies everything needed: what it returns, how it relates to the sibling, and where the id comes from. No output schema, but return contents are described in prose.

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% and the id parameter is already documented in-schema as coming from a fr_property_sales result. The description reinforces that lineage and clarifies that the id refers to a whole transaction (not a parcel), which is marginally useful, but the baseline of 3 applies since the schema carries the load.

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 (returns one transaction) and resource (a French property 'mutation' identified by DVF id_mutation). Explicitly distinguishes itself from fr_property_sales, which lists sales, so the agent can tell the two apart without opening either 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?

Gives the explicit sequencing rule: 'Use after fr_property_sales to see the full set of parcels in a specific sale.' Names the sibling and the condition that selects this tool, leaving nothing to inference.

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