start_activity

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does reveal fuzzy matching and backdate semantics, but omits critical side effects for a state-changing tool: what happens if an activity is already being tracked, whether starting overwrites the current status, permissions needed, or any return/error behavior. This is a meaningful transparency gap.

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 two sentences, front-loaded with the primary purpose, and each clause adds necessary information (type identification, backdating options). No wasted words or repetition of schema details.

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?

The tool has five parameters, no required parameters, no annotations, and no output schema. The description does not clarify whether at least one of type_id/type_name is required, nor does it explain typical success/failure responses or conflicts with an in-progress activity. This level of ambiguity makes the description incomplete for a state-changing tool, despite good parameter-level coverage.

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 already fully documents all five parameters, so the baseline is 3. The description adds value beyond the schema by noting that type_name is fuzzy matched, pointing to list_activity_types for valid names, and clarifying that at and started_minutes_ago are alternative backdating mechanisms. This helps an agent choose between the two backdate options.

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 tracking an activity'), the resource (activity), and the key input modes (type name or type_id). It distinguishes itself from sibling tools like stop_activity and pause_resume_activity by explicitly being about starting tracking.

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 clear context: use this to start tracking an activity, with guidance to consult list_activity_types for fuzzy name matching. It does not explicitly mention exclusions (e.g., when not to use), but the context is unambiguous enough for an agent to select it appropriately over siblings.

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