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

With zero annotations, the description carries the load and does disclose the two behaviors that matter most: the permission model (self vs. owner/office) and the invariant of one running clock per person per shop with stop_running as the remedy. It omits what happens if a clock is already running and stop_running is not passed (error vs. implicit stop), which is the main remaining behavioral unknown.

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?

Three compact sentences, front-loaded with the core action, then permissions, then the running-clock constraint — no filler and nothing repeated.

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?

For a 7-parameter mutation with an output schema (so return values need no explanation) and no annotations, the description covers the critical permission and concurrency semantics. It falls slightly short only on the already-running-clock failure mode and on undocumented parameters like notes.

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 only 43%, and the description only partially compensates: it adds the visit-assignment condition behind a visit-based clock, but never explains notes, visit_id, job_id, or shop_id directly, and the category/stop_running semantics it states largely restate the schema's own field descriptions. Baseline 3 is appropriate given the partial coverage gap.

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?

Opening clause states a specific verb and resource ("Start a person's clock") and immediately enumerates the four categories it covers (work/drive/shop/break), which maps directly onto the enum. An agent can distinguish this from timesheets_clockOut or timesheets_add from the text alone.

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?

Gives concrete when-to-use context: field workers may clock only themselves and only on a visit they're assigned to, while owner/office can clock anyone; it also explains the stop_running escape hatch for switching categories. It never names the sibling tools (timesheets_clockOut, timesheets_current) an agent might need next, so it stops short of full alternative routing.

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