clock_in

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

With no annotations, the description is the sole source of behavioral disclosure. It reveals one behavior: refusal when an interval is open. However, it provides no details on side effects, success behavior, idempotency, permissions, or what happens to the provided parameters. For a write operation, this is insufficient transparency.

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 extremely brief (two sentences) and front-loads the main action. It is not verbose, but it sacrifices utility for brevity. The refusal condition adds value, but the lack of any parameter or usage context makes it under-specified rather than concise in a helpful way.

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 7 parameters, no annotations, and no parameter descriptions, the description is far from complete. An agent cannot confidently invoke this tool without additional knowledge about the arguments. The output schema exists but does not compensate for the missing parameter semantics and behavioral context.

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 input schema has 7 parameters with 0% description coverage. The description adds no meaning to any parameter (effort, kind, note, external, internal, work_slice, participants). An agent cannot infer which fields are required, what 'effort' expects, or how 'external' vs 'internal' influence the interval. The description completely fails to compensate for the schema's lack of explanations.

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 states a specific action ('Start an interval') and a key constraint ('Refused if one is already open'). It clearly indicates what the tool does, though it doesn't explicitly differentiate from sibling tools like start_effort or clock_out. The resource (interval) and verb are precise enough for basic selection.

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 gives no guidance on when to use this tool versus alternatives. It only implies that it should not be used when an interval is already open. No mention of scenarios where start_effort or other siblings would be more appropriate. An agent must infer usage from the name alone.

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