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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, so the bar is lower; the description adds the meaningful scope fact that there is no date bound and that results include a per-day breakdown. It does not cover what happens when no entries exist or when the name is ambiguous.

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 the scope ('all-time'), the resource, and the returned measures packed in; every clause carries information and nothing is 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?

For a one-parameter read tool with no output schema, the description usefully names the return fields and the per-day breakdown, which is what an agent needs to decide whether to call it. Only edge-case behavior (no results, multi-match names) is left unaddressed, and the schema covers the matching rule.

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 single 'client' parameter already documents partial-name matching, so the baseline is 3. The description only reinforces that exactly one client/project is in scope, adding little beyond the schema.

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 description states a specific resource (one client/project) and enumerates the returned aggregates: hours, entry count, billable amount, plus a per-day breakdown. It is clearly distinguishable from summary_day and summary_week via the 'all-time' scope, though it never names those siblings explicitly.

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 only implied: 'all-time totals' signals this is the unbounded version versus the day/week siblings, but there is no explicit when-to-use or when-not-to-use statement. An agent must infer that filtering by date range means calling summary_day/summary_week instead.

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