time_summary

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

With no annotations, the description carries the burden and does so well: it discloses the 92-day maximum range, that dates are inclusive, the available grouping modes, and the required record:read permission. What it does not cover is output shape or how totals are formatted, leaving a small gap for a no-annotation tool.

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?

Two tight sentences: the capability and its bounds come first, then the use case. No filler and no repetition of the 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 three-parameter aggregation tool with no output schema, the description covers scope, grouping, limits, and auth requirements so an agent can call it correctly. The only omission is any hint about the shape of the returned totals, which is minor given the group_by field.

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 coverage is 100%, so the baseline is 3, and the description adds a real constraint the schema omits: the 92-day maximum span between date_from and date_to. It also restates the grouping vocabulary, which the schema already enumerates, so value beyond baseline is moderate rather than rich.

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 operation (totaling hours logged) over an explicit resource (time records) with a bounded date window and three named groupings. It is clearly distinguishable from siblings like list_time_blocks, which return raw entries rather than aggregated totals.

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?

Gives concrete use cases ('how much time did I spend on X', writing a work log or diary entry), which tells the agent when this tool is the right pick. It does not explicitly name or exclude the alternative listing tools, so it stops short of full when-not guidance.

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