start_timer

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states the action ('Start a new timer') but omits critical details: whether this requires authentication, what happens if a timer is already running (e.g., stops previous timer, returns error), rate limits, or what the response contains. This is inadequate for a mutation tool with zero annotation coverage.

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 appropriately sized with a clear purpose statement followed by parameter explanations. The structure is front-loaded with the main action, and each sentence adds value. Minor improvement could come from integrating parameter details more seamlessly, but overall it's efficient with minimal waste.

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 complexity (mutation with 3 parameters), lack of annotations, and no output schema, the description is incomplete. It fails to explain behavioral aspects (e.g., timer conflicts, response format), usage context relative to siblings, or parameter dependencies. For a tool that likely interacts with other time-tracking functions, this leaves significant gaps for an agent.

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 description coverage is 0%, so the description must compensate. It lists all three parameters with brief explanations, adding meaning beyond the schema's titles. However, it lacks details like format constraints (e.g., integer ranges for IDs), what happens if notes are omitted (default is null), or how project/task IDs relate to other tools. This provides basic but incomplete semantic context.

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 new timer') and resource ('timer'), making the purpose immediately understandable. However, it does not explicitly differentiate from sibling tools like 'create_time_entry' or 'stop_timer', which could cause confusion about when to use each tool.

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 provides no guidance on when to use this tool versus alternatives like 'create_time_entry' or 'stop_timer'. It lacks context about prerequisites (e.g., whether a timer must be stopped first) or typical scenarios for starting timers, leaving the agent without usage direction.

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