start_timer

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

Annotations indicate the tool is idempotent and not read-only or destructive. The description adds that it validates the issue and returns a start timestamp, which aligns with the idempotent hint. There is no contradiction, and the description provides useful behavioral context.

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, front-loaded with purpose, every sentence adds value. No wasted words.

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 required params, no nested objects), the description covers purpose, validation, output, and workflow hint. Output schema exists, so return values are documented. Complete for the agent to use 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 parameter descriptions ('a string that will be trimmed'). The tool description does not add additional meaning beyond what the schema provides. Baseline of 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 action ('start a client-side timer'), the resource ('a Huly issue'), and provides specific details: validates issue existence and returns a start timestamp. This distinguishes it from siblings like log_time and stop_timer.

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 explicitly tells the agent to use log_time when done, providing a clear workflow. It does not explicitly exclude other usage, but the context is sufficient for an agent to decide when to invoke this tool.

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