time_summary

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

With no annotations provided, the description carries the full transparency burden and does so well. It explicitly warns that all figures are heuristics, not measured focus time, and explains edge cases like agent_minutes being 0 where no turn-end signal exists and browser sources lacking that signal. It also discloses the local-timezone dependency and the inclusion of a short tail credit in active_minutes.

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?

Although long, the description is dense and efficiently front-loaded: purpose first, then metric semantics, then parameter semantics, then a critical caveat. Every sentence adds non-obvious information, and nothing is redundant with the input schema.

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 only three simple parameters but complex derived metrics, the description is remarkably complete. It covers defaults, accepted formats, metric definitions, known limitations, timezone handling, and how to present results, making it self-sufficient for an agent to invoke correctly. The output schema can handle the mechanical return structure.

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 fully compensates by explaining every parameter. It enumerates all valid group_by values, gives concrete syntax for since/until (ISO 8601, bare dates, 'now', relative durations), explains the meaning of relative durations, and specifies the default behavior for both parameters.

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 opening 'Where the user's time went. THE tool for any question about time use, focus or workload' gives a specific verb-like purpose and a clear resource scope, and it is immediately distinguishable from sibling tools such as prompt_stats or activity_timeline. The description further reinforces purpose by enumerating the exact metrics returned.

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 gives clear practical usage context: defaults, how to omit 'until', valid group_by values, timezone behavior, and relative duration semantics. It positions itself as the tool for time-use questions but does not explicitly name alternatives or say when not to use it, so it stops short of a 5.

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