metrics_metric_timer_start

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

No annotations are provided; the description discloses the return of a timer_id string and concurrent timer behavior. However, it does not mention error handling, default behavior, or impact on system resources, leaving gaps for an agent.

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, front-loaded with the primary action. Each sentence provides essential information without waste, making it efficient for an agent to parse.

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 the return value and concurrency behavior, fitting the tool's simplicity. It lacks mention of missing required parameter handling or interaction with metrics storage, but for a basic timer start, it is adequate.

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 name parameter is only typed as a string in the schema with no description. The description adds meaning by explaining its role in identifying the timer for stopping and allowing concurrency, which compensates for the 0% schema coverage.

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 starts a timer for measuring elapsed time and returns a timer_id. It distinguishes the tool from its sibling metric_timer_stop by indicating the timer_id should be passed to stop.

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 notes that multiple timers with the same name can run concurrently, providing context on concurrency. It implicitly directs usage toward pairing with metric_timer_stop, but does not explicitly state when not to use or compare with other timer tools.

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