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

Annotations already indicate read-only, idempotent, and non-destructive behavior. The description adds context by enumerating allowed range values and specifying that results include totals and rankings, which goes beyond the structured fields. No contradiction exists.

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?

The description is a single, front-loaded sentence that efficiently conveys the resource, the range values, and the result structure. Every clause adds meaningful information with no repetition or fluff.

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?

Given the schema's lack of parameter descriptions, the description covers the core purpose and primary parameter well, but does not address optional parameters. The existence of an output schema reduces the need to explain returns, but overall completeness is moderate for a tool with this complexity.

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?

Input schema has 0% description coverage, so the description must compensate. It explains the 'range' parameter with valid values and implies 'user_id', but leaves 'project', 'timeout', and 'writes_only' unexplained. This is insufficient for a 5-parameter tool.

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 clearly states the tool fetches aggregated WakaTime coding stats for a user, with explicit scope (range values) and output (totals and rankings). This distinguishes it from sibling tools like durations or heartbeats, which focus on raw or granular data.

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 implies usage for aggregated coding stats over time ranges but does not explicitly mention alternatives or when not to use this tool. Sibling tools like durations or summaries exist, but no differentiation is provided, so guidance is left to inference.

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