format_duration

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

With no annotations, the description carries the full behavioral burden, yet it only says it formats a time interval. It does not disclose the resulting string format (e.g. '1h 30m' vs '01:30:00'), rounding behavior, or locale, which is the single most important thing to know about a pure formatting function.

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 short phrase, front-loaded with the verb and resource and free of padding. Brevity here reflects under-specification rather than wasted words, but there is genuinely nothing redundant to trim.

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?

There is no output schema, so the description is responsible for conveying the shape of the returned display string, and it does not. For a tool whose entire value is the produced format, this leaves a significant gap in what an agent needs to use the result 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 description coverage is 100%, so the sole parameter 'seconds' is already documented in the schema. The description adds no extra semantics (no unit clarification beyond the schema, no range constraints), so the baseline of 3 applies.

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 ('格式化时间间隔显示') essentially restates the tool name format_duration, adding only the word 'interval' where the name says 'duration'. It gives no hint of the output format or the unit/convention used, so an agent cannot distinguish what this produces versus a generic formatting helper.

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 guidance on when to call this tool versus alternatives, no mention of acceptable input ranges, and no note of what happens with negative or fractional seconds. The sibling tools (send_notification, set_task_start_time) are unrelated, so no routing is needed, but the description offers no usage context at all.

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