active_timers

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

Annotations are absent, so the description carries the full behavioral burden. It conveys that only active timers scoped to the current user are returned, which implies a read-only listing operation, but it never explicitly states that there are no side effects or what happens when no timers are active.

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 a single short phrase with no wasted words, and it front-loads the key concept of currently running entries. It could be stronger as a full sentence with an explicit verb like 'Returns', but it is appropriately sized for a zero-parameter listing tool.

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 tool with no parameters and an output schema, the description provides enough information to understand the tool's purpose and scope: active timers belonging to the current user. It does not discuss alternatives or edge cases, but those are less critical given the tool's simplicity.

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 is empty and schema description coverage is 100%, so there are no parameters to document. The 'for this user' qualifier adds implicit auth-scoping context beyond the schema, which is useful, and the 0-parameter baseline applies.

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 identifies the resource as 'currently running time entries' for the current user, which maps directly to the tool name and distinguishes it from historical entries. It uses a noun phrase rather than a verb+resource form, and it doesn't explicitly name sibling tools, so it is clear but not maximally directive.

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 guidance is provided about when to use this tool versus siblings like recent_entries, start_timer, stop_timer, or restart_timer. The phrase 'currently running' implies a listing use case, but there is no explicit when-to-use or when-not-to-use direction.

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