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

With no annotations, the description carries the full burden. It discloses that the diff is recursive and that results are categorized as added/removed/changed, which is genuine behavioral context. But it says nothing about output format, ordering, or the fact that this is a read-only comparison, and there is no output schema to fill that gap.

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?

A single front-loaded sentence with no filler, stating verb, inputs, and output categories. It is efficient, though arguably too terse given the undocumented nested parameter structure.

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 tool with a nested object schema, no annotations, and no output schema, the description covers the semantics of the result but leaves the input shape and return structure unexplained. It is minimally adequate rather than complete.

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% and the single parameter is a nested object whose cryptic fields 'a' and 'b' are undocumented. The phrase 'between two JSON documents' only weakly implies that a and b are the two inputs being compared, so the description does not compensate for the coverage gap.

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 states a specific verb (recursive diff) and resource (two JSON documents), and even names the output categories: added, removed, changed paths. It is clear enough to distinguish from json_query and json_validate. However, it never explicitly contrasts against the sibling json_flatten or text_diff, leaving the differentiation to inference.

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 no when-to-use guidance, no prerequisites, and no mention of alternatives such as text_diff (for strings) or json_query (for extraction). Usage is only implied by the tool name and description; an agent gets no routing help.

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