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

With no annotations provided, the description carries the full burden. It discloses that values are discarded, but omits any side effects, network calls, or security considerations. The schema hints at behaviors like 'no disk access' and 'discarded after the call', but the description does not consolidate these, leaving the agent uninformed about the tool's operational traits.

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 two sentences and efficiently states the core function. It is front-loaded with the action, but it is so brief that it sacrifices essential context, making it concise yet under-specified.

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?

Given the tool's complexity (9 optional parameters, no output schema, no annotations), the description is severely incomplete. It does not explain what the tool returns, how to use it with the various parameter types, or why it exists alongside siblings. An agent would struggle to know when and how to invoke 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?

The schema has 100% description coverage for all 9 parameters, so the baseline is 3. The description adds no parameter-specific meaning beyond the schema, so it does not exceed this baseline.

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 action (count keys) and resource (JSON object), but it is terse and does not differentiate from sibling shape-checking tools like validate-json or domain-shape. It also doesn't mention that the tool accepts multiple input types (url, file path, etc.) as shown in the schema, making its scope unclear.

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 provides no guidance on when to use this tool versus alternatives. It does not mention any conditions, prerequisites, or exclusions, leaving the agent to infer from the name and schema alone.

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