x402node_time_duration

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

With no annotations provided, the description must fully disclose behavior. It states the output is a human-readable breakdown of years, months, days, hours, minutes, seconds, but does not explain timezone handling, behavior for inverted dates, or what happens when `end` is omitted (though schema says default now). The price note is irrelevant to behavior.

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 plus an irrelevant price line. The first sentence is a list of 12 synonyms, which is somewhat redundant and wastes space. The core purpose is front-loaded in the second sentence. The price line adds no value for tool selection or invocation.

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 simplicity (2 params, no output schema), the description provides a basic understanding but lacks details on return format structure, timezone handling, error cases, or limits. It mentions 'human-readable breakdown' but does not specify the exact fields or order, which would be helpful for invocation.

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%, so the schema already provides parameter descriptions. The description adds no additional meaning beyond what is in the schema (e.g., format constraints, examples). Baseline 3 is appropriate.

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's function: 'Compute the duration between two timestamps with human-readable breakdown.' It also lists multiple alternative phrasings (duration calculator, time difference, etc.), but the core verb+resource is explicit and distinct from sibling tools like cn402_age_calc and x402node_time_format-relative.

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 lists many use cases (days between dates, hours between times, age calculator, etc.) implying when to use it, but it does not provide explicit guidance on when to prefer this tool over siblings or when not to use it. No exclusions or comparisons are given.

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