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

Even with annotations present, the description adds substantial behavioral context: transactional application, 100-operation limit, strict pointer handling, safe object properties, bounded intermediate results, per-call billing, and the recovery implication that a new requestId triggers a new billable operation. This goes well beyond the annotations and aligns with idempotentHint=true without contradicting any annotation.

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 description is compact and information-dense with no filler. Each sentence earns its place: the first defines what the tool does, the second announces the paid nature, the third gives the required setup, and the fourth clarifies recovery/billing semantics.

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 complex paid tool with a nested schema, the description covers the essential operational context: prerequisites, billing, limits, transactionality, safety constraints, and recovery behavior. An output schema is present, so the absence of return-value details is not a gap. An agent has enough information to invoke and recover from the tool 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?

The schema already documents requestId and maxPriceMicroUsd, so the baseline is 3. The description adds meaningful context by tying requestId to agent_utilities_prepare, recovery, and billable-operation semantics, and by explaining that maxPriceMicroUsd can act as a recovery-only control ('0 means recovery only' is in the schema, but the description reinforces its role in the billing flow).

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 opens with a specific verb ('Apply'), a precise standard ('RFC 6902'), a bound ('up to 100 operations'), and a clear resource ('supplied JSON'). It also states distinctive properties like transactional execution and strict pointers, making it easy to distinguish from sibling tools such as data_json_pointer, data_json_diff, and data_json_canonical.

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 gives clear context for use: it is a paid tool, it requires prior setup via agent_utilities_prepare, it needs existing credits and a private Authorization header, and it explains recovery by reusing prepared arguments. It does not explicitly name alternatives or state when not to use this tool, but the steps and preconditions are unambiguous.

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