Start timer

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

With no annotations, the description carries a heavy burden, and it does well by explicitly revealing that a new timer stops and logs the previous one, names it, and that rate applies only to this timer. It could disclose more failure modes or naming details, but the key side-effect is clearly stated.

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 well ordered: it states the action, the important side effect, and then the parameter nuance. Every sentence carries useful information without repetition or filler.

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 that the tool has five parameters and no output schema, the description covers the main return value (start time) and the most important behavioral edge case (one timer at a time). The full parameter semantics are already in the schema, so this is reasonably complete, though it could be more explicit about failure cases or naming behavior.

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 baseline is 3. The description adds real value by clarifying that rate is expressed in MAJOR currency units and is timer-scoped, which helps avoid common misinterpretation of the rate parameter.

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 uses a specific verb and resource: start a stopwatch for project work, and it explicitly says it returns the start time. It also distinguishes the tool behavior from siblings by describing the one-at-a-time rule where starting a new timer stops and logs the previous one.

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?

It is clear that the tool is used for starting a timer, and the one-active-timer rule gives an important constraint. However, it never mentions sibling tools like timer_stop or timer_status, nor does it explicitly say when an agent should prefer those alternatives.

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