duration_elapsed

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

With no annotations, the description carries the full burden and does disclose the stateful lifecycle: auto-start on first call, cumulative return thereafter, and reset behavior. It omits other traits an agent would want, such as whether state persists across sessions/connections, what happens with a supplied started_at, or any error behavior.

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?

Compact and front-loaded: the core purpose comes first, followed by the lifecycle rules in semicolon-separated clauses. Every clause earns its place with no filler, though the density leaves some behavior (return format) unaddressed rather than wasted.

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?

No output schema exists, so the description should at least sketch what is returned; it states only conceptually that it returns 'how long has elapsed' without unit/format. Given all six parameters are well documented in the schema and the lifecycle is covered, the definition is adequate but not fully complete.

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 100%, so all six parameters are already documented in the schema and the baseline is 3. The description reinforces the reset (restart timing) and auto-start (started_at) semantics but adds no syntax, format, or default details beyond what the schema already states.

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?

States a specific verb+resource: it records a task start moment and returns elapsed time, which is a clear, distinct purpose. It does not explicitly name or contrast against siblings such as time_until, current_time, or agent_clock, so an agent must infer the difference from the cumulative-per-session semantics.

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 clearly explains the call lifecycle (first call auto-starts, later calls return cumulative duration, reset=true restarts), which is useful implied usage guidance. However, it never states when to prefer this tool over siblings like time_until or current_time, so alternative routing is left to inference.

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