Timer status

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

With no annotations, the description carries the full burden of behavioral disclosure. It explicitly states the tool writes nothing, eliminating side-effect concerns, and precisely defines the 'today' boundary with the 23:30-crossing-midnight example. This is substantive behavioral context beyond the name and schema.

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 with no filler: core purpose first, then the one tricky date-boundary detail, then a concise no-arguments/no-writes confirmation. Every sentence earns its place.

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 zero-argument, read-only status tool, the description covers invocation and the key date-boundary rule well. It does not specify the exact response shape or what happens when no timer is running, and with no output schema that is a small but real gap.

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 schema has zero properties and 100% coverage, and the description clearly says 'No arguments.' There are no parameters to document, so the baseline 4 applies and is fully satisfied.

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 'Report' as a specific verb and clearly identifies the resource: the running timer and today's total hours. It does not explicitly contrast itself with siblings such as report or entry_list, so it stops short of a 5.

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?

'No arguments, and it writes nothing' implies this is a safe, read-only status check with no setup required, which conveys when it would be appropriate. However, it never names alternatives or gives explicit when-not-to-use conditions, so the routing guidance is only implied.

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