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

Annotations already declare readOnlyHint=true and idempotentHint=true, so safety is covered. The description adds valuable behavioral detail: it returns a precise parse error with position if invalid, which informs the agent of failure behavior. This is beyond what annotations provide and is useful for handling errors.

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, no fluff. The first sentence states core functionality, the second adds error behavior and usage guidance. Information is front-loaded and every clause earns its place.

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?

The description covers validation, formatting modes, optional key sorting, and error reporting. Given the tool's moderate complexity, full schema coverage, and presence of an output schema, the description is complete enough for an agent 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?

Schema coverage is 100% with each parameter fully described (input, mode with enum, sort_keys with default). The description repeats the mode and sort behavior without adding new meaning, so it does not elevate beyond the baseline of 3. It confirms the intended use but doesn't offer extra insight.

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 clearly states the tool validates JSON and can pretty-print or minify it, with optional key sorting. This is a specific verb + resource ('Format / validate JSON') and differentiates from sibling tools by focusing on JSON processing rather than encoding, hashing, or generation.

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 context: 'Use to check and clean JSON instead of eyeballing it.' This indicates when the tool is appropriate, though it does not explicitly mention when not to use it or alternatives. The guidance is clear enough for an agent to select it for JSON validation/formatting needs.

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