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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered; the description adds useful non-structured detail by disclosing the aggregation shape (per-project breakdown) and the default-resolution rule. It stops short of mentioning whether running timers are counted or how rounding works.

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 front-loaded sentence with no filler; the scope, default, and output shape all earn their place.

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 simple read-only aggregate with rich annotations and no output schema, the description plus schema is largely sufficient. Minor gaps remain around timezone/'local' semantics and whether in-progress timers contribute to the total.

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% and the description's 'local date, default today' simply restates the schema's own parameter description verbatim, adding no extra syntax, format, or edge-case meaning. Baseline 3 is appropriate when the schema does all the work.

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 ('Total hours logged') with an explicit scope ('one calendar day') and output granularity ('broken down per project'). The day-scope implicitly separates it from summary_week, though no sibling is named outright.

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?

Usage is implied by the narrow scope (one calendar day, default today), but there is no explicit when-to-use guidance and no mention of when to prefer summary_week or summary_client instead. An agent must infer the routing decision.

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