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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world scope, so the safety profile is covered. The description adds genuine behavioral detail beyond that: the week boundary rule (Mon-Sun, local dates, week containing today) and the per-project grouping. It still omits anything about data freshness, whether zero-hour projects appear, or billed/unbilled treatment.

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?

A single sentence that front-loads the metric, then the time window, then the grouping. Every clause earns its place and nothing is repeated from the title or annotations.

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?

With zero parameters and no output schema, the description must convey the return shape, and it does: total hours, weekly window, per-project breakdown. Small gaps remain around output format (decimal hours vs 'H:MM'), empty-week behavior, and whether all projects or only active ones are listed, but for a zero-arg read tool this is largely sufficient.

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 tool takes no parameters, so the schema carries no semantic burden and the baseline is 4. The description correctly introduces no parameter prose, and the only 'argument-like' content — the date window — is hard-coded behavior rather than an input.

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 concrete resource and metric ('Total hours logged'), plus the exact time window ('week containing today, Mon-Sun, local dates') and the breakdown dimension ('per project'). The week scope implicitly separates it from summary_day and summary_client, but those siblings are never named, so differentiation requires inference from the sibling list.

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?

No explicit when-to-use, when-not-to-use, or alternative routing is given. Usage is only implied by the resource itself — an agent must infer that this is the weekly roll-up versus summary_day, summary_client, or report. Adequate but leaves routing decisions to the caller.

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