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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds genuinely non-obvious behavior: streets in the same IRIS yield identical data, and no quantified difference is returned when source dates don't allow verified temporal comparison. These are real disclosure of output behavior beyond the annotations, though the telegraphic phrasing makes them slightly hard to parse.

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 three telegraphic fragments are short and front-load the count constraint, but the compression tips into ambiguity — "sans gagnant" and the temporal-comparison clause require interpretation rather than being crisp statements. Dense but not optimally structured.

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?

An output schema exists so return values need not be explained, but for a comparison tool with an undocumented dimensions parameter and no routing guidance versus callejear_get_street_context, the description leaves important gaps. The cryptic fragments do not fully prepare an agent to call it correctly.

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 0%, so the description must carry the parameter burden. "Deux à cinq rues" merely restates the street_ids minItems/maxItems already enforced by the schema, and the optional "dimensions" parameter is not mentioned at all, leaving its enum semantics undocumented.

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 conveys the resource ("Deux à cinq rues") and a key scope constraint ("sans gagnant"), but never states a clear verb like "comparer" — the action is only inferable from the tool name. It does not explicitly distinguish itself from the sibling callejear_get_street_context, leaving the comparison intent implicit.

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?

There is a hint of the operating constraint (2-5 streets) and a caveat that no numeric difference is shown when source dates don't permit a verified temporal comparison, but no explicit when-to-use or when-not-to-use versus siblings like get_street_context or get_coverage. The agent must infer the selection context.

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